Botany & Zoology
Welcome to Stellenbosch University

 

 

New book is treasure trove of information on invasive species https://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=7408New book is treasure trove of information on invasive species Corporate Communication / Korporatiewe Kommunikasie [Alec Basson]<p>​​If you're concerned about invasive species or always wanted to know more about them, then a new book on all aspects of biological invasions in South Africa is definitely for you.<br></p><p>Published recently as an open access encyclopaedic book, <a href="https://link.springer.com/book/10.1007/978-3-030-32394-3"><strong class="ms-rteThemeForeColor-5-0">Biological Invasions in South Africa</strong></a> provides the reader with information on 1 422 alien species including, among others, plants, birds, mammals, fish, terrestrial invertebrates, invasive marine organisms and disease-causing microorganisms that have naturalised or become invasive in the country. </p><p>Comprising 31 chapters, it covers themes such as the history of research in South Africa, detailed accounts of major groups of plants and animals, policy development, the development of a robust ecological theory about biological invasions, the effectiveness of management interventions and scenarios for the future regarding biological invasions in the country.</p><p>“There are very few, if any, books that give such a comprehensive coverage of this field at a national level, for any country in the world. While there are many books on biological invasions, most cover a particular aspect of the problem, or a particular group of species," says Prof Brian van Wilgen from the <a href="http://academic.sun.ac.za/cib/"><span class="ms-rteThemeForeColor-5-0"><strong>Centre of Excellence for Invasion Biology</strong></span></a> (CIB) and the Department of Botany and Zoology at Stellenbosch University. He co-edited the book with colleagues Profs John Measey and Dave Richardson as well as Prof John Wilson and Dr Tsungai Zengeya from the South African National Biodiversity Institute. Over 100 researchers, practitioners and post-graduate students working on different aspects of invasive species contributed to the book.</p><p>​Van Wilgen says they wanted to produce a comprehensive reference work that can be used as a teaching and research tool and a source of information for managers in the field. <br></p><p>“This book provides information on the known impacts of invasive species in the country.<br></p><p>For example, alien trees consume about 5% of our scarce water resources, reduce the carrying capacity of our natural rangelands and are a direct threat to the survival of almost half of 1 600 native species listed in South Africa's Red Data List.</p><p>“Particularly damaging species include American and European pine trees and Australian acacias that invade the fynbos and grasslands, reduce water runoff, threaten native species (some of which are only found in South Africa) and increase the severity of wildfires; American mesquite (<em>Prosopis</em>) trees that invade the arid Karoo and dry savannas, making livestock production almost impossible on some farms; and a new arrival, the invasive polyphagous shothole borer, a beetle set to wipe out plane trees, oaks, avocados and many other trees species across South Africa."</p><p>As to the reason behind the book, Van Wilgen says the last (and only) synthesis of this topic at a national level was published 34 years ago in 1986, and a new synthesis of this large and growing problem was needed. “Our government has invested a substantial amount into the establishment and running of the CIB over the past 15 years, so it was also necessary to review what we have learnt, and to provide a comprehensive synthesis for use by the next generation of researchers and managers."<br></p><p>He adds that their comprehensive coverage was possible for a number of reasons, including South Africa's long history as a leader in dealing with invasive species (both in research and in management) and generous funding made available for research, training and management over the past 20 years.<br></p><p>“South Africa has also emerged as a world-leading nation in this field, punching well above its weight in research, training and management. Since its inception in 2004, the CIB has published 1 750 research papers, and conferred master's and doctoral degrees on 129 and 67 candidates respectively. This is a significant contribution to capacity-building and transformation in this field."<br></p><p>The hope is that the book will remain a major reference work and teaching tool for many years to come – not only in South Africa, but also globally, says Van Wilgen.<br></p><p>“It will also doubtless be widely used beyond our borders, and we particularly hope that it will be useful for other countries in Africa."<br></p><ul><li><em>Biological Invasions in South Africa</em> can be downloaded for free at<strong class="ms-rteThemeForeColor-5-0"> </strong><strong class="ms-rteThemeForeColor-5-0"><a href="https://link.springer.com/book/10.1007/978-3-030-32394-3">https://link.springer.com/book/10.1007%2F978-3-030-32394-3</a>.</strong></li></ul><p><strong>FOR MEDIA ENQUIRIES ONLY</strong></p><p>Prof Brian van Wilgen</p><p>Centre of Excellence for Invasion Biology</p><p>Department of Botany and Zoology<br></p><p>Stellenbosch University</p><p>​Email: <a href="mailto:bvanwilgen@sun.ac.za"><span class="ms-rteThemeForeColor-5-0"><span><strong>b</strong></span><span><strong>vanwilgen@sun.ac.za</strong></span></span></a> </p><p><strong>ISSUED BY</strong></p><p>Martin Viljoen</p><p>Manager: Media</p><p>Corporate Communication<br></p><p>Stellenbosch University</p><p>Email: <a href="mailto:viljoenm@sun.ac.za"><strong class="ms-rteThemeForeColor-5-0">viljoenm@sun.ac.za</strong></a> </p><p> </p><p> </p><p><br> </p>
Young ecologist receives prestigious Robert May awardhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=7312Young ecologist receives prestigious Robert May awardMedia & Communication, Faculty of Science<p>​​​​​Dr Corneile Minnaar, a postdoctoral fellow in the Department of Botany and Zoology at Stellenbosch University (SU), was awarded the <a href="https://www.britishecologicalsociety.org/publications/best-paper-by-an-early-career-researcher/robert-may-prize/">Robert May early career researcher award</a> for the best paper published in the journal <em>Methods in Ecology and Evolution</em> (MEE) in 2019. </p><p>This annual award is named after Lord May from the University of Oxford. <a href="https://www.theguardian.com/science/2020/apr/29/robert-may-former-uk-chief-scientist-led-chaos-theory-lord-dies-aged-84">Robert May</a> was a physicist and ecologist, best known for applying mathematical techniques to understand the relationship between complexity and stability in natural communities. Along with the prize, the winner also receives £250 and membership of the British Ecological Society (BES).</p><p>Dr Minnaar received the award for his article “<a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/2041-210X.13155">Using quantum dots as pollen labels to track the fates of individual pollen grains</a>". The article is based on work for his PhD under the guidance of Prof Bruce Anderson of the Department of Botany and Zoology at SU.</p><p>Dr Minnaar explains: “A central component of an organism's fitness is its ability to successfully reproduce. This includes finding a potential mate and successful mating. For plants, movement of pollen from an anther to a conspecific stigma is essential for successful reproduction, but directly tracking movement of individual pollen grains heretofore has been impossible."</p><p>This is important, because knowing how pollen move around, and whether or not they successfully fertilise ovules, is central to understanding the evolution of ecology of flowering plants and floral traits.</p><p>Dr Minnaar <a href="/english/Lists/news/DispForm.aspx?ID=6231">used quantum dots to track pollen grains</a> by placing very small volumes of quantum dots (suspended in hexane) directly onto anthers and following the movement of the dots from one plant to another.</p><p>According to a media release from the <a href="https://www.britishecologicalsociety.org/">British Ecological Society</a>, this cost-effective methodology, at about US$0.02 per flower, will provide new opportunities to explore central open questions in plant biology.</p><p>The method has now been published and Dr Minnaar has since been awarded an NRF Innovation Postdoctoral Fellowship, as well as a Technology and Innovation Seed Fund grant. He is currently working closely with industry partners such as <a href="https://www.koppert.co.za/">Koppert Biological Systems</a> to develop more sustainable and effective pollination methods.</p><p>Minnaar says he is grateful for the fact that the journal has formally recognised the painstaking effort of method development: “Methods developed for studies of ecology and evolution used to be relegated to supplementary materials, scribbled in notebooks or shared between colleagues. For this reason, this journal [<em>Methods in Ecology in Evolution</em>] is one of my favorite journals."<br></p>
More than 600 degrees in the natural sciences awarded at SU’s December graduationhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=7009More than 600 degrees in the natural sciences awarded at SU’s December graduationWiida Fourie-Basson<p>​​​Dressed in traditional Zulu-attire, Maties student Menzi Ngcamphalalala today proudly walked across the stage to receive his MSc degree in Mathematics. He was one of the more than 600 graduate and postgraduate students in the natural sciences who received their degrees during Stellenbosch University's fifth graduation ceremony on 11 December 2019.<br></p><p>Amongst these were a whopping nine PhDs in Chemistry and Polymer Science, while another 29 students received their MSc-degrees in Mathematics as part of the African Institute for Mathematical Sciences' (AIMS) programme. All in all, the Faculty of Science awarded 390 BSc, 145 BScHons, 55 MSc and 29 PhD degrees. <br></p><p>Another MSc student in Mathematics, <a href="/english/Lists/news/DispForm.aspx?ID=7007">Sarah Selkirk​</a>, was also awarded the prestigous S2A3 medal (bronze) of the Southern African Association for the Advancement of Science (SAAAS) for the best MSc student at Stellenbosch University across the natural, engineering and medical sciences.<br></p><p>Prof Louise Warnich, Dean of SU's Faculty of Science, says she is grateful for the hard work put in by lecturers, study leaders and students, despite the many challenges faced by higher education institutions in South Africa. Since 2015, the Faculty of Science has consistently produced more than 300 postgraduate students per year, and it seems the year 2019 will be no exception.</p><p>“Our graduandi continue to make important contributions to the private and public sectors in South Africa, many of them as leaders and entrepreneurs. I am confident that the class of 2019 will follow in their footsteps and apply their hard-earned, high-level skills for the advantage and development of our society."</p><p>Some of the highlights from this year's graduandi include a PhD in Biochemistry awarded to <a href="/english/Lists/news/DispForm.aspx?ID=7005">Dr Collins Jana</a>, currently a lecturer at the University of Malawi's College of Medicine. Back in 2014, when he embarked on a career focusing on research into the development of new drugs to fight infectious diseases, there were no higher education institutions in Malawi offering postgraduate options in biochemistry. That was the start of a ten-year long journey as a postgraduate student in the research group of Prof Erick Strauss in SU's Department of Biochemistry.</p><p>Another highlight is the achievement of Dr Upenyu Lucky Muza, who not only earned a PhD in Chemistry under the supervision of Prof Harald Pasch, but in August this year he was one of only five postgraduate students nation-wide to receive the <a href="http://www.saci.co.za/saci_awards.html">SASOL Postgraduate Medal</a> from the South African Chemical Institute (SACI), awarded to postgraduate students who are innovative, entrepreneurial and independent. Formerly from Zimbabwe, he is off to Europe next year for a postdoctoral fellowship.<br></p><p>Another highlight is a PhD in Computer Science awarded to Dr Arnu Pretorius, who entered the field of machine learning and deep neural networks with a background in statistical mathematics. While many regard algorithms more as an art than a science, he developed a more principled design process in which decision are guided by theoretical developments. <a href="/english/Lists/news/DispForm.aspx?ID=7006">Read more​</a> about his work with study leader Dr Steve Kroon from the Computer Science Division in the Faculty of Science.</p><p>The Department of Botany and Zoology also made their mark this year, with five PhD-students graduating. Dr Luyanda Ndlela isolated and characterized three predatory bacteria that may one day become pivotal in finding natural treatments for toxic algal blooms; Dr Olivier Pasnin, a research scientist at the Mauritius Oceanography Institute, did the first phylogenetic analysis of sponges in the Western Ocean, thereby contributing to improved marine conservation practices. Other PhD graduates looked at the evolutionary history and taxonomy of parasitoid wasps, the drivers of Prosopis invasions in Eastern Africa, and the role of marine predators in regulating invasions.</p><p>Another three PhDs were awarded in Physics, three in Mathematical Science, two in Physiological Sciences and one each in Applied Mathematics and Microbiology</p><p><em>Photos: Stefan Els</em></p>
Shark Safe Barrier™ tested at popular beach resort on La Réunion Islandhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6686Shark Safe Barrier™ tested at popular beach resort on La Réunion IslandWiida Fourie-Basson<p>​Shark-deterrent technology developed by a team from Stellenbosch University is now being tested of the coast of La Réunion Island in the Indian Ocean.<br></p><p>The <a href="https://www.sharksafesolution.com/">Shark Safe Barrier™</a> is the most advanced shark-specific deterrent technology currently available that do not injure or kill sharks and other marine animals, while keeping surfers and swimmers safe.<br></p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="https://www.youtube.com/embed/Ypqj7zraPc4" frameborder="0"></iframe> </div><p><br></p><p>For mobile users <a href="https://www.youtube.com/watch?v=Ypqj7zraPc4">click here</a>.<br></p><p>The technology has been in development for the past seven years by SU's <a href="https://www.sharksafesolution.com/the-team/">Dr Sara Andreotti and Professor Conrad Matthee</a>, in collaboration with well-known conservationist Michael Rutzen, Dr Craig O'Connel from the USA and South African coastal engineer Laurie Barwell. The team combined two well-known aspects of shark biology, their natural dislike of dense kelp-forests and their sensitivity to magnetic fields, to come up with a barrier that will physically separate sharks and people from each other.</p><p>In practice it consists of several rows of staggered high-density polyethylene pipes that are positioned one meter apart on the sea bed in order to imitate a dense kelp forest. The ocean-facing row contains large ceramic magnets, creating a strong magnetic field to further deter the sharks from entering.</p><p>The concept has been piloted and tested in the stormy waters of Gansbaai, regarded as the mecca of great white sharks in South Africa. During the two years of trials not a single shark have entered an artificially-created kelp barrier of 169 square meters, even though tempted with fish bait and chum.</p><p><strong>Invention to be tested outside South African waters for the first time</strong></p><p>In 2014 the Shark Safe Barrier™ was commercialized with the help of SU's technology transfer company, Innovus.</p><p>Now its chief operating officer, Dr Andreotti was approached in 2017 by <a href="https://www.sharksafesolution.com/shark-attack-capital-of-world-trials-new-eco-friendly-shield-to-halt-deaths/">La Réunion's Shark Risk Management Centre to test their invention's effectiveness with bull sharks in the Indian Ocean</a>.</p><p>“During January and February 2019 we installed a 100 square meter barrier of the coast of Saint-Paul. Twice a week, chum and fish bait are released in the middle of the square by Reunion researchers to lure sharks. The structure has already formed an artificial reef and has become a refuge for local fish, but so far, no sharks has approached the enclosure," she says.</p><p>The field test will be completed after the Réunion team has recorded interactions with at least 20 bull sharks.</p><p>Between 2007 and 2016, this surfers' paradise has seen seven fatal and 14 non-fatal shark incidents, with a subsequent drop in tourist bookings of 40% after each of these unfortunate events.</p><p>“In 2014 tourists totaled almost half of the population on the island. But today the authorities warn residents and tourists to stay out of the water" says Andreotti.</p><p>If successful, the installation of the Shark Safe Barrier™ along this popular coastline could mean a turn-around for the island's ailing tourism industry. </p><p>But, more importantly, it could also mean a turn-around for the <a href="https://www.youtube.com/watch?v=1sEbPFSq_rI">oceans' threatened shark populations</a>.</p><p>“Between 2011 and 2016, there have been 491 registered shark attacks worldwide, of which 43 proved fatal. Meanwhile, thousands of sea creatures have been killed by getting entangled in shark nets, or fished by drumlines," Andreotti says.</p><p><strong>Crowdfunding for one more test</strong></p><p>The team is currently working on improving the robustness of the Shark Safe Barrier™ technology by adapting the anchorage system to better secure the pipes on sandy sea beds. It then needs to be exposed to real sea condition for one more time.</p><p>For this exercise, the team plans to raise $24 000 through the crowdfunding platform <a href="https://www.thundafund.com/project/sharksafebarrier">Thundafund</a> at <span style="font-size:12pt;font-family:"times new roman", serif;"><a href="https://www.thundafund.com/project/sharksafebarrier" target="_blank">https://www.thundafund.com/project/sharksafebarrier</a></span><br></p><p>If this last test is successful, the Shark Safe Barrier invention is one step closer to be rolled-out to beaches all over the world, to the benefit of both humans and the oceans' marine animals, Andreotti concludes.<br></p><p><strong>Media enquiries</strong></p><p>Dr Sara Andreotti</p><p>E-mail: andreottisara@gmail.com</p><p>Cell: 27(0)72 321 9198<br></p><p><br></p><p><br></p>
Quantum dots used to capture act of speciationhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6593Quantum dots used to capture act of speciationWiida Fourie-Basson<p>​​Using quantum dots as a tool to trace the pollen of the long-tubed iris, <em>Lapeirousia anceps</em>, evolutionary ecologists from Stellenbosch University have succeeded in capturing a snapshot of a plant in the process of speciation.</p><p><a href="/english/faculty/science/botany-zoology/research">Professor Bruce Anderson</a>, an evolutionary ecologist in the <a href="/english/faculty/science/botany-zoology">Department of Botany and Zoology</a> at SU, says this is only the third time in his research career where he has found a contact zone where speciation appears to be happening right in front of our eyes.<br></p><p>​“Contact zones of entities in the process of diverging may actually be quite common, but they are hard to find because you really need to know what to look for," he postulates.<br></p><p>For the  past 15 years Anderson and his associates have been visiting a patch of West Coast sand-plain fynbos just outside the small town of Mamre on South Africa's West Coast, a 45 minute drive from Cape Time along the N7 highway.</p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="https://www.youtube.com/embed/0l9prp9ebYk" frameborder="0"></iframe> </div><p>​This is one of the prime spots where the long-tubed iris, <em>Lapeirousia anceps</em> can be found, as well as its pollinator, the long-tongue fly, <em>Moegistorhynchus longirostris</em>.</p><p>“Think of the famous example of the Madagascar star orchid with its 30cm nectar tube and <a href="https://www.theguardian.com/science/lost-worlds/2013/oct/02/moth-tongues-orchids-darwin-evolution">Darwin's moth</a> with an almost equally long tongue," Anderson explains, “where the orchid and moth have coevolved in an escalating race scenario." </p><p>The same evolutionary mechanism behind matching of pollinator tongues and floral tubes is true for <em>Lapeirousia</em>.<br></p><p>In 2009 a fellow researcher, <a href="https://www.researchgate.net/publication/232679123_FLIES_AND_FLOWERS_IN_DARWIN%27S_RACE">Professor Anton Pauw</a>, found that <em>Lapeirousia</em> has tube lengths which have coevolved with the tongue lengths of its fly pollinator, <em>Moegistorhynchus longirostris, </em>where tongues and tubes can vary from 43-86mm, depending on the study site. In other words, the tube-lengths of the plants match perfectly with the tongue-length of the pollinators, depending on the geographical location of the different populations. </p><p>But in 2003 Anderson stumbled upon a strange population of <em>Lapeirousia anceps</em> in the Mamre area: “Some plants had short floral tubes and others had long tubes, and very few plants had tubes of intermediate length. Yet this population of plants was visited by only a single species of the long-tongued fly, <em>Moegistorhynchus longirostris</em>."</p><p>For the next 15 years, Anderson and his colleagues studied this population and found that there was little gene flow between the two plants forms, which explained why they had remained as two separate entities for so long.</p><p>“In other countries with fewer plant species, biologists would have been sorely tempted to call these forms different species, but we have so many species already that we can afford to be a little more circumspect!" he laughs.</p><p>Anderson was much more interested in finding the mechanisms that prevented the two forms from mixing in the first place.</p><p>On one of the many photographs from his field work, he noticed a long-tongued fly from that area with pollen on the top of its head and then another clump of pollen halfway down its tongue. But because these plants are so recently diverged, they couldn't tell the pollen apart.</p><p>“I was sure that the pollen on the head was from the long-tubed flowers and the other pollen from the short-tubed flowers, but I had no way of showing this."</p><p><strong>Quantum physics to the rescue</strong></p><p>When Corneile Minnaar joined the group as a PhD student in 2015, he decided to try and find a reliable method to label and track pollen in order to answer this question. By the end of his first year, he succeeded in <a href="/english/Lists/news/DispForm.aspx?ID=6231">using quantum dots to label pollen grains</a>, thereby breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.</p><p>During November 2015 and 2016, the team set off to Mamre to test the newly-designed method in the field, and, more importantly, to test Anderson's hypothesis.</p><p>In the case of <em>Lapeirousia</em> and the long-tongued fly, Minnaar and Anderson were now able to show conclusively that long- and short-tubed flowers place and receive pollen on different parts of the fly's long tongue: short tubed flowers mostly midway and long-tubed flowers on or near the head. </p><p>Consequently, pollen seldom moves between long and short tubed individuals, indicating a barrier to the flow of genes.</p><p>Professor Andersons says it looks as if they have captured these plants in the very act of speciation: “This is quite unusual, because normally when you see plants they have diverged long ago and it is very difficult to tell the processes by which they diverged. This is different. We've managed to capture these plants in the act of speciation and we were able to identify the process and mechanisms by which it is taking place."</p><p>He says it is hard to predict whether these two forms of <em>Lapeirousia</em> will remain separate forever or eventually unify. But what he does know is that this patch of land needs to be protected.</p><p>“It is severely threatened, heavily grazed and invaded by acacias and grasses," he warns. “There is a very real possibility for this unique patch of sand-plain fynbos to disappear in the not too distant future."</p><p>The article “<a href="https://doi.org/10.1111/nph.15971">Intraspecific divergence in floral-tube length promotes asymmetric pollen movement and reproductive isolation</a>" was published in the journal <em>New Phytologist</em> this month, with authors Dr Corneille Minnaar, Dr Marinus de Jager and Professor Bruce Anderson.</p><p><strong>Media enquiries</strong></p><p>Prof Bruce Anderson<br> Department of Botany and Zoology, University of Stellenbosch<br> Tel: (021) 808 3586<br> Cell:  072 113 6948</p><p>E-mail: banderso.bruce@gmail.com<br> <a href="http://www.biointeractionslab.com/prof.-bruce-anderson.html">http://www.biointeractionslab.com/prof.-bruce-anderson.html</a></p><p><strong>Captions</strong></p><p>With a tongue up to 7 cm in length, the long-tongue fly <em>Moegistorhynchus longirostris</em> often battle to fly, especially in the wind. The fly must fully insert its proboscis into the flower to obtain a tiny droplet of nectar at the bottom of the tube, and in the process pollen is placed on or removed from its head by the long-tubed iris, <em>Lapeirousia anceps</em>.<strong> </strong><em>Photo: Bruce Anderson</em></p><p><br></p>
From zero to hero for South Africa’s common wood sorrelhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6565From zero to hero for South Africa’s common wood sorrelWiida Fourie-Basson<p>Over the past 15 million years South Africa's common wood sorrel has developed an arsenal of the most unique and extreme germination strategies in the Cape Flora.<br></p><p>Yet the same strategies that have allowed these delicate little plants to grow and survive in the most uninhabitable places thinkable – think of the <a href="https://biotaxa.org/Phytotaxa/article/view/phytotaxa.314.2.4">Richtersveld</a>, <a href="https://www.google.com/search?safe=active&rlz=1C1CHBH_enZA764ZA766&ei=faoxXY-1L_yj1fAPw9iA6AE&q=Oxalis+new+species&oq=Oxalis+new+species&gs_l=psy-ab.3..33i160.34593.37785..37886...3.0..1.408.5259.2-10j5j2......0....1..gws-wiz.......35i39j0i67j0i131j0i131i67j0j0i20i263j0i22i30.1GHOmO6VlRc&ved=0ahUKEwjP5_a98cDjAhX8URUIHUMsAB0Q4dUDCAo&uact=5">Knersvlakte</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0254629908002780">Oorlogskloof </a>and Gifberg – may now be to its detriment under a fast changing climate.</p><p>In a study published in the <a href="https://www.ncbi.nlm.nih.gov/pubmed/31157415"><em>American Journal of Botany</em></a> recently, Dr Michelle Jooste from the Department of Botany and Zoology at Stellenbosch University describes a continuum of germination states for 64 species of <em>Oxalis</em>: from germinating within 24 hours (called recalcitrant seeds) to lying dormant for several years, while waiting for the ideal environmental conditions to germinate (called orthodox seeds).</p><p><a href="/english/Lists/news/DispForm.aspx?ID=4468">Prof Léanne Dreyer</a>, one of the co-authors and a leading expert on southern African <em>Oxalis</em>, says the wood sorrel's germination strategies are nothing short of weird, extreme and unique in the plant kingdom.</p><p><em>“Oxalis</em> had to adapt to a Mediterranean climate subjected to long hot and dry summers alternating with a very predictable wet winter rainfall season. Dealing with these two extremes, which have remained stable for the past 15 million years, enabled <em>Oxalis</em> to take germination strategies to a whole new level," she explains.</p><p>Even more unique is the incidence of inverse germination in some <em>Oxalis</em> species, where the seed leaves and the first foliar leaf develop rapidly and appear to sustain rapid growth of the seedling before the radicle and root hairs subsequently emerge.</p><p>“This is a remarkable phenomenon," says Dreyer, “and it is happening at the speed of light, as the plant needs to have enough time and produce sufficient resources within a single growing season to also form a bulb in order to survive underground during the hot, dry summer months."<br></p><p><img src="/english/faculty/science/PublishingImages/News%20items/Oxalis%20germination_Facebook.png" class="ms-rtePosition-4" alt="" style="margin:5px;width:497px;" /><br>​But it doesn't end here. The researchers have noticed that some of the recalcitrant species produce large amounts of a thick gluey substance (called mucilage) upon germination. They are now investigating the presence of bacteria in the mucilage, which appear to be symbiotically associated with these seeds – a symbiosis is when two or more organisms live together in a close mutually beneficial association.<br></p><p>Even more extreme are those <em>Oxalis</em> species of which the seeds are capable of either rapid germination or staying dormant: “These seeds have the benefit of immediate germination if environmental conditions are favorable, or to delay germination until conditions become more favorable," Dreyer explains.</p><p>These types of seeds are extremely rare. In the case of <em>Oxalis</em>, only 19% of the 64 species studied – selected to be as representative as possible of the nearly 230 known southern African <em>Oxalis</em> species – displayed intermediate germination.</p><p>Intermediate and recalcitrant species (56%) are almost exclusively restricted to the winter rainfall areas of the Cape, while orthodox species (24%) are present in both summer and winter rainfall areas.</p><p>Dreyer says they regard the orthodox strategy as the ancestral state among <em>Oxalis</em> species. The big question now is whether <em>Oxalis</em> has one more survival strategy in its arsenal to deal with drier conditions and a less predictable winter rainfall in the Cape Floristic Region as predicted by models of future climate change.</p><p>“If not, we stand to lose more than 50% of Cape <em>Oxalis</em> species – that is more than 115 species!" she concludes.</p><ul><li>The article “<a href="https://www.ncbi.nlm.nih.gov/pubmed/31157415"><em>Oxalis</em> seeds from the Cape Flora have a spectrum of germination strategies</a>" was published in the <em>American Journal of Botany.</em> The authors are Dr Michelle Jooste, Professor Guy Midgley and Professor Léanne Dreyer from Stellenbosch University, and Dr Kenneth Oberlander from the University of Pretoria. <br></li></ul><div><br></div><div><strong>On the photo above</strong>, within 24 hours, a day-old seedling of <em>Oxalis gracilis</em> with opened seed leaves between which the first foliar leaf is starting to develop. Note that the radicle is still completely underdeveloped, and the seedling is imbedded in a mucilage. <em>Image: Léanne Dreyer</em><br></div><div><em><br></em></div><div><p><strong>Media enquiries</strong></p><p>Prof Léanne Dreyer</p><p>Department of Botany and Zoology, Stellenbosch University</p><p>Tel: +27 _21 808 3070</p><p>E-mail: <a href="mailto:ld@sun.ac.za">ld@sun.ac.za</a><br></p></div><p><br></p>
Genetic blueprint for extraordinary wood-munching fungus from the Northern Capehttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6244Genetic blueprint for extraordinary wood-munching fungus from the Northern CapeWiida Fourie-Basson<p>A relatively unknown fungus, accidentally found growing on an Acacia tree in the Northern Cape, has emerged as a voracious wood-munching organism with enormous potential in industries based on renewable resources.<br></p><p>The first time someone took note of <a href="https://mra.asm.org/content/8/1/e01429-18"><em>Coniochaeta pulveracea</em></a> was more than two hundred years ago, when the South African-born mycologist Dr <a href="https://www.first-nature.com/fungi/~biog-persoon.php">Christiaan Hendrik Persoon</a> mentioned it in his 1797 book on the classification of fungi.</p><p>Now <em>C. pulveracea</em> has had its whole genome sequenced by microbiologists at Stellenbosch University (SU) in South Africa, and henceforth made its debut in cyberspace with a few <a href="https://twitter.com/search?f=tweets&vertical=default&q=%23Coniochaeta&src=typd">tweets</a> and a hashtag. All because this relatively unknown fungus has an extraordinary ability to degrade wood – hence the descriptor “<em>pulveracea"</em>, meaning powdery.<img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/cpulveracea%20small.jpg" alt="cpulveracea small.jpg" class="ms-rtePosition-2" style="margin:5px;" /><br></p><p>In the age of biotechnology, biofuels and the usage of renewable raw materials, this is an important fungus to take note of, says <a href="/english/faculty/science/microbiology/research/a-botha">Prof Alf Botha</a>, a microbiologist in the <a href="/english/faculty/science/microbiology">Department of Microbiology</a> at SU.</p><p>Over the past 25 years, there has been a number of reports on the ability of species in the <em>Coniochaeta</em> genus to rapidly degrade lignocellulose into fermentable simple sugars. But thus far Prof Botha's lab is the only one to be working on <em>C. pulveracea</em>.</p><p>The work started in 2011, when he quite randomly snapped a brittle twig, covered in lichen, from a decaying Acacia tree. At the time, he was holidaying with family on a farm in the Northern Cape. “At the time we were looking for fungi and yeasts that can break down wood, so I knew this was something special when I decided to keep the twig," he explains. But to date, despite numerous attempts, they have not been able to find it again.</p><p>However, back in the lab there was great excitement when they observed that this species in the <em>Coniochaeta</em> genus was literally munching its way through birchwood toothpicks. Even more astounding was its ability to change form between a filamentous fungus and a yeast, depending on the environment.</p><p>“This is highly unusual for a fungus. We'd typically expect this kind of behavior from some fungal pathogens," explains Botha.</p><p>Over the past decade Botha and his postgraduate students focused on unraveling this yeast-like fungus' behavior. In 2011 Dr Andrea van Heerden found that it produced enzymes that degraded the complex structures of wood into simple sugars, feeding a community of surrounding fungi that do not have the ability to degrade wood. In 2016, she published the results of her investigation into its ability to switch to a yeast-like growth. Understanding this process would be important to the potential use of this fungi in industrial processes.</p><p>In the latest study, MSc student CJ Borstlap worked with <a href="/english/faculty/science/microbiology/research/h-volschenk">Dr Heinrich Volschenk</a> , an expert molecular biologist, and Dr Riaan de Witt from the <a href="/english/faculty/science/sci-bioinformatics">Centre for Bioinformatics and Computational Biology</a> at SU, to produce the first draft genome sequence of <em>C. pulveracea</em>. With a genome size of 30 million nucleotides and over 10 000 genes, this was no easy task. In the process he picked up the necessary coding skills to identify and name all 10 053 genes, and to identify those responsible for the wood-degrading character of the fungus.</p><p>Dr Volschenk says the next step is to understand the fungus' mechanism of breaking down wood and producing sugars on a molecular level: “With the genetic blueprint now available, we can study the network of genes and proteins the fungus employs to convert wood and other similar renewable resources into more valuable products," he explains.</p><p>The sequence data for <em>C. pulveracea</em> have been deposited at the DNA Data Bank of Japan (DDBJ), the European Nucleotide Archive (ENA) at Cambridge, and GenBank in the United States of America, under the accession number QVQW00000000 and is freely available to all researchers in this field.</p><p>The article “Draft Genome Sequence of the Lignocellulose-Degrading Ascomycete <em>Coniochaeta pulveracea</em> CAB 683" was published in the American Society for Microbiology's journal <em>Microbiology Resource Announcements</em> on 3 January 2019 and is available online at <a href="https://mra.asm.org/content/8/1/e01429-18">https://mra.asm.org/content/8/1/e01429-18</a></p><p><strong>On the photos above:</strong></p><p>Cells of the wood-eating fungus, <em>Coniochaeta pulveracea</em>, exhibit both yeast- and fungus-type characteristics while breaking down twigs from an Acacia tree. Image: Heinrich Volschenk</p><p>Microbiologists from Stellenbosch University produced the first whole genome sequence of the wood-eating fungus, <em>C. pulveracea</em>. This relatively unknown and hard-to-find fungus has emerged as a voracious wood-munching organism with enormous potential in industries based on renewable resources. They are, from left to right, Prof Alf Botha, MSc-student CJ Borstlap, Dr Heinrich Volschenk and Dr Riaan de Witt. Photo: Stellenbosch University</p><p><strong><br></strong></p><p><strong>Media enquiries</strong></p><p>Prof Alf Botha</p><p>Department of Microbiology, Stellenbosch University</p><p>Tel: +27 021 808 5856</p><p>E-mail. <a href="mailto:abo@sun.ac.za">abo@sun.ac.za</a></p><p> <br></p><p>Dr Heinrich Volschenk</p><p>Department of Microbiology, Stellenbosch University</p><p>Tel: +27 021 808 5851</p><p>E-mail: <a href="mailto:volschenkh@sun.ac.za">volschenkh@sun.ac.za</a></p><p> </p><p>Mr CJ Borstlap</p><p>Mobile: 0784122262</p><p>E-mail: <a href="mailto:17536669@sun.ac.za">17536669@sun.ac.za</a><br><br></p>
Quantum dots used to track flowers’ pollenhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6231Quantum dots used to track flowers’ pollenWiida Fourie-Basson​A pollination biologist from <a href="/english/">Stellenbosch University</a> is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.<p>In an article published in the journal <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/2041-210X.13155"><em>Methods in Ecology and Evolution</em></a> this week, <a href="https://www.researchgate.net/profile/Corneile_Minnaar">Dr Corneile Minnaar</a> describes this novel method, which will enable pollination biologists to track the whole pollination process from the first visit by a pollinator to its endpoint – either successfully transferred to another flower's stigma or lost along the way.<br></p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="https://www.youtube.com/embed/YHs925F13t0" frameborder="0"></iframe> </div><p>(<a href="https://youtu.be/YHs925F13t0">Mobile users click here</a> for video)<br></p><p>Despite over two hundred years of detailed research on pollination, Minnaar says, researchers do not know for sure where most of the microscopically tiny pollen grains actually land up once they leave flowers: “Plants produce massive amounts of pollen, but it looks like more than 90% of it never reaches stigmas. For the tiny fraction of pollen grains that make their way to stigmas, the journey is often unclear—which pollinators transferred the grains and from where?"</p><p>Starting in 2015, Minnaar decided to tread where many others have thus far failed, and took up the challenge through his PhD research in the Department of Botany and Zoology at Stellenbosch University (SU).</p><p>"Most plant species on earth are reliant on insects for pollination, including more than 30% of the food crops we eat. With insects facing rapid global decline, it is crucial that we understand which insects are important pollinators of different plants—this starts with tracking pollen," he explains.</p><p>He came upon the idea for a pollen-tracking method after reading an article on the use of quantum dots to track cancer cells in rats (<a href="https://doi.org/10.1038/nbt994">https://doi.org/10.1038/nbt994</a>). Quantum dots are semiconductor nanocrystals that are so small, they behave like artificial atoms. When exposed to UV light, they emit extremely bright light in a range of possible colours. In the case of pollen grains, he figured out that quantum dots with “fat-loving" (lipophilic) ligands would theoretically stick to the fatty outer layer of pollen grains, called pollenkitt, and the glowing colours of the quantum dots can then be used to uniquely "label" pollen grains to see where they end up.</p><p>The next step was to find a cost-effective way to view the fluorescing pollen grains under a field dissection microscope. At that stage Minnaar was still using a toy pen from a family restaurant with a little UV LED light that he borrowed from one of his professors.</p><p>“I decided to design a fluorescence box that can fit under a dissection microscope. And, because I wanted people to use this method, I designed a box that can easily be 3D-printed at a cost of about R5,000, including the required electronic components."</p><p>So far, the method and excitation box have proven itself as an easy and relatively inexpensive method to track individual pollen grains: “I've done studies where I caught the insects after they have visited the plant with quantum-dot labelled anthers, and you can see where the pollen is placed, and which insects actually carry more or less pollen."</p><p>But the post-labelling part of the work still requires hours and hours of painstaking counting and checking: “I think I've probably counted more than a hundred thousand pollen grains these last three years," he laughs.</p><p>As a postdoctoral fellow in the research group of <a href="http://www.biointeractionslab.com/index.html">Prof Bruce Anderson</a> in the <a href="/english/faculty/science/botany-zoology/Pages/default.aspx">Department of Botany and Zoology</a> at Stellenbosch University, <a href="http://www.biointeractionslab.com/dr-corneile-minnaar.html">Minnaar </a>will continue to use the method to investigate the many unanswered questions in this field.</p><p>The article, “Using quantum dots as pollen labels to track the fate of individual pollen grains" was published on Wednesday, 13 February 2019, in the journal <em>Methods in Ecology and Evolution</em> and is available online at <a href="https://doi.org/10.1111/2041-210X.13155">https://doi.org/10.1111/2041-210X.13155</a> (an earlier non-peer reviewed version of the article is available for free on bioRxiv: <a href="https://doi.org/10.1101/286047">https://doi.org/10.1101/286047</a>)<br></p><p><em>On the photo above (left), </em><em>Dr Corneile Minnaar, a pollination biologist in the Department of Botany and Zoology at Stellenbosch University, developed a technique which uses quantum dots to track individual pollen grains, thereby breaking new ground in a field of research that has been hampered by lack of a universal method to track pollen for over a century. </em><em>Photo: Stefan Els</em><br></p><p><i>On the photo (right), Pollen grains, labelled with green, yellow, and red quantum dots, on a stigma and viewed viewed here inside the excitation box. Files for 3D-printing the box can be found online at <a href="https://doi.org/10.1111/2041-210X.13155">https://doi.org/10.1111/2041-210X.13155</a>. <em>Photo: Corneile Minnaar</em></i></p><p>​​ </p><p><strong>Media enquiries</strong></p><p>Dr Corneile Minnaar</p><p>Department of Botany and Zoology, Stellenbosch University</p><p>Tel: 082 313 0725</p><p>E-mail: corneile@sun.ac.za</p><p style="text-align:center;"><em>Media release issued by Wiida Fourie-Basson, Media: Faculty of Science, Stellenbosch University, South Africa</em></p><p style="text-align:center;"><em>+27 021 808 2684</em><em>        </em><a href="mailto:science@sun.ac.za"><em>science@sun.ac.za</em></a><em>           </em><em>@scienceSUN​</em></p>
African Union recognises SU world leader in invasion biologyhttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6198African Union recognises SU world leader in invasion biologyMedia & Communication, Faculty of Science<p>Prof Dave Richardson from the <a href="http://academic.sun.ac.za/cib/team/staff/dmrichardson/">DST-NRF Centre of Excellence for Invasion Biology</a> (CIB) at Stellenbosch University (SU) and a world leading scientist in the field of invasion biology, is the recipient of the 2018 <a href="https://scholarship-positions.com/african-union-kwame-nkrumah-awards-for-scientific-excellence-auknase-africa/2018/07/05/">Kwame Nkrumah Award for Scientific Excellence</a>.<img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/David%20Richardson-15_small.jpg" alt="David Richardson-15_small.jpg" class="ms-rtePosition-2" style="margin:5px;width:281px;" /><br></p><p>This continental award is one of three awards made annually by the <a href="https://au.int/en/announcements/20180611/african-union-kwame-nkrumah-awards-scientific-excellence-auknase-continental">Commission of the African Union</a> to recognise outstanding African scientists for their achievements, discoveries and innovations. Established in 2008 in memory of the well-known Pan-Africanist leader Dr Kwame Nkrumah, the continental award includes a monetary award of US$100 000.</p><p><a href="http://academic.sun.ac.za/cib/team/staff/dmrichardson/">Prof Richardson</a> is a distinguished professor in the Department of Botany and Zoology at SU, James Marsh Professor-at-Large at the University of Vermont in the United States of America, and director of the CIB, one of the most productive and influential research groups working in the field of biological invasions in the world. Biological invasions are a rapidly growing threat to biodiversity and ecosystem functioning in Africa and many parts of the world.<br></p><p>Prof Richardson says he is extremely honoured to receive this award: “I hope that it will help to spread awareness of the massive problems with invasive species worldwide, and the urgent need for innovative solutions to prevent the escalation of impacts on biodiversity and human livelihoods."</p><p>He also commended South Africa's Department of Science and Technology and Stellenbosch University for their substantial investments in this field through their funding of the CIB: “The Centre has created a critical mass of knowledge and expertise across disciplines to address diverse issues pertaining to biological invasions in Africa."<br></p><p>Prof Louise Warnich, Dean of the Faculty of Science, says the award is yet another well-deserved recognition of Prof Richardson's significant contributions to the field of invasion biology: “The awards confirms his status as an influential international leader in this field. The CIB has continued to blossom under his leadership and he is an excellent role model for young researchers."</p><p>The Award Ceremony will be held at the AU Conference Center on 10 February 2019 during the Assembly of the AU Heads of States (The Summit) in Addis Ababa, Ethiopia.</p><p><strong>More about Prof Richardson</strong></p><p>Prof Richardson is regarded as one of the most influential authors globally in the field of invasion science. His research focusses on biological invasions, and in particular the dynamics of plant invasions, specifically trees and shrubs. He has worked predominantly on invasive species in South Africa, mainly in the fynbos and savanna biomes, but has also published widely on invasive species in other parts of Africa and the world, on global patterns and trends in biological invasions, and on developing a sound theoretical basis for invasion science.</p><p>One of his major contributions to invasion science has been the thorough development and exploitation of new model systems for the elucidation of all the diverse perspectives that need to be considered to understand and manage invasive species. His contributions on the ecology of pines and Australian acacias are widely recognised as foundation studies in invasion science.</p><p>Prof Richardson has also contributed substantially to the formulation of practical guidelines for the improved management of invasions. He is frequently consulted by conservation agencies and government departments, and serves on various committees related to environmental management in South Africa and abroad.</p><p>He is currently one of only a handful of African scientists rated as a “Highly Cited Researcher" by Clarivate Analytics – these are scientists who rank in the top 1% by citations for their field in the Web of Science and are making an impact in solving some of the world's biggest challenges. He has received numerous awards, including the Hans Sigrist Prize (2006), the John F.W. Herschel Medal from the Royal Society of South Africa (2012), and the Havenga Prize for Life Sciences from the South African Academy for Science and Arts (2013). In 2019 he received a third successive A1 rating from the National Research Foundation, reflecting his status as a world leader in invasion science.<br></p><p><em>On the photo, Prof Dave Richardson. Photographer: Anton Jordaan</em></p>
New crab species discovered in Eastern Cape ‘forgotten’ forestshttps://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6105New crab species discovered in Eastern Cape ‘forgotten’ forestsDane McDonald<p>​A new 'pearl white' freshwater crab species has been discovered in the 'forgotten' Eastern Cape forests of South Africa.<br></p><p>Prof Savel Daniels, a molecular taxonomist at Stellenbosch University, says crabs are relatively well studied in South Africa but for some reason forests have been neglected in sampling efforts.</p><p>“Nobody has ever intensively sampled the forests in the Eastern Cape where we (incidentally) found the species at Mbotyi," he told the FBIP.</p><p>The study formed part of the Eastern Cape Forest project, one of the Large Integrated Projects funded by the Foundational Biodiversity Information Programme (FBIP).</p><p>Mbotyi is a picturesque forested region northeast of Port St Johns and adjacent to the East Coast of South Africa.</p><p><strong>'Sympatry'</strong></p><p>The crab, which shimmers in the presence of light, was collected from under stones found in small streams which flow towards the coast.</p><p>In a case of what phylogeographers call 'sympatry' the pearl white crab lives alongside a known rust brown species belonging to the African freshwater crab genus <em>Potamonautes.</em></p><p><em><img class="ms-rtePosition-2" src="/english/faculty/science/PublishingImages/News%20items/Crabfigure5.jpg" alt="" style="margin:5px;width:300px;" /></em> </p><p>Like a divorced couple who still share the same house, the two related [but genetically distinct] populations are sympatric because they exist in the same geographic area and thus frequently encounter one another without breeding.</p><p>In a sense Daniels was lucky to have discovered the specimen with its striking colour difference compared to its counterpart, <em>P. sidneyi</em>. </p><p>In recent times and particularly with invertebrates, such discoveries, where the scientist has a clear morphological difference as a 'lead' for identifying a potential new species, are rare.</p><p><strong>'Colour morphs'</strong></p><p>In Daniels' line of work he often encounters 'cryptic species' where animals which are similar to the human eye are genetically very different. In other cases animals look different but show no significant genetic differences – different 'morphs'.</p><p>Daniels set out to answer whether the two crabs were indeed different species, or less spectacularly, two superficial 'colour morphs' with the one being pearl white and the other rust brown.</p><p>Back in the laboratory at the Stellenbosch University Evolutionary Genomics Facility samples from both groups of animals were subjected to DNA sequencing, looking at three genes known by geneticists as 'COI, 12S rRNA, and 16S rRNA'.</p><p><strong>DNA sequence divergence</strong></p><p>The DNA sequence divergence (i.e. the genetic difference) for the COI gene, usually a primary marker in animal genetic studies, was striking at 13.42%. </p><p>To gain a better perspective on divergence values molecular taxonomists need to look at which values from prior studies were used to designate something as sufficiently different to be called a 'new species'. </p><p>Daniels' paper, published in the <em>Journal of Crustacean Biology</em>, cited two prior studies with values ranging from 2.8% to 14.7% in the one, and 7.9% between two species in the other.</p><p>There could be no doubt that the shimmering pearl white specimen from Mbotyi was a new species to science.</p><p>Daniels found no morphological characteristics with which to distinguish <em>P. sidneyi</em> from the new Mbotyi species except for the striking colour difference. The latter was inspiration for the naming of the new species, one of the few opportunities for creativity in describing a new species.</p><p>As a tribute to the Xhosa people of the Mbotyi region Daniels decided to give the newly discovered crab the species epithet of <em>mhlophe</em>, meaning 'white' in isiXhosa.</p><p>He says the discovery is important as it highlights the biodiversity of the area, and further establishes the region as a 'biodiversity hotspot', a tourism draw card.</p><p>“Tourism in the region creates a lot of sustainable job opportunities," he says.</p><p>The Foundational Biodiversity Information Programme (FBIP) is a long-term programme to generate, manage and disseminate foundational biodiversity information and knowledge to improve decision-making, service delivery and create new economic opportunities.</p><ul><li>FBIP on Facebook and Twitter<br></li></ul><p>For more details contact:</p><p>Contact:             Dane McDonald  </p><p>Designation:     Science communicator</p><p>Cell:                 +27 (0) 72 1299 649</p><p>Email Address: d.mcdonald@sanbi.org.za</p><p>Website:                           http://fbip.co.za/<br></p><p><br> </p>