Phytophthora Root Rot

FABI News

News Archive

23 Apr 2024

FABIans attend EPN conference in Spain

FABIans Prof. Brett Hurley and Innocent Rakubu attended a congress in Spain to celebrate a century of the discovery of Steinernema kraussei Steiner.

22 Apr 2024

Congratulations Firehiwot!

FABI congratulates Dr Firehiwot Eshetu on the successful completion of her PhD degree.

19 Apr 2024

FABIans celebrate Jackie Robinson Day

Some 60 FABIans gathered at the University of Pretoria’s LC de Villiers sports campus on the afternoon of 15 April to celebrate Jackie Robinson Day.

19 Apr 2024

Using art as a gateway to systems thinking, biomedical careers and health equity

Dr Jeb Owen presented an interesting and thought-provoking seminar “Using art to scaffold systems thinking and biomedical career pathways in young learners” at FABI’s Monday Morning Meeting.

12 Apr 2024

Nature Africa highlights novel research conducted at FABI on <i>Sirex</i> egg activation

Nature Africa highlights novel research conducted at FABI on Sirex egg activation

The newly-developed Sirex egg activation technique, developed by FABI researchers, is highlighted in a news item by Nature Africa.

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FABI Events

25 April 08h30

Student Seminars

29 April 08h30

Monday Morning Meeting

FABI in a nutshell

Research Features

Archive

A new study reveals the presence of Mycotoxins in Eastern Cape maize in South Africa.

Eurotiales update: FABIans Prof. Cobus Visagie and Dr Neriman Yilmaz and their collaborators have published a review of recently described Eurotiales species, including the economically important Aspergillus, Penicillium, Paecilomyces and Talaromyces.

Da Vinci's Yeast: FABIans Prof. Cobus Visagie, Dr Neriman Yilmaz, and their collaborators have recently described and named a newly discovered yeast species of the famous Italian painter, draughtsman, engineer, scientist, theorist, sculptor, and architect Leonardo da Vinci.

The potential economic impact of the PSHB invasion in South Africa has been calculated to be a massive R275 billion over the next ten years, if nothing is done to stop the spread of this invasive beetle. Researchers from FABI collaborated with Stellenbosch University ecologists and economists to model the unmitigated economic impact of this invasion.

A recently published paper in the journal Current Forestry Reports documents a collaboration between an international team of forest pathologists and invasion scientists. Led by Dr Trudy Paap, the authors present a framework for conceptualizing and managing invasive forest pathogens.

A recently published review article by Dr Andi Wilson in a special issue of the journal 'Microbiology & Molecular Biology Reviews' provides details of the genes that are essential to the sexual cycle in filamentous Ascomycete fungi and further describes their functions in a variety of model and non-model species.

Penicillium section Canescentia re-evaluated and five new species described from the fynbos biome in South Africa.

In November 2019, the DSI-NRF Centre of Excellence for Invasion Biology hosted a workshop on ‘Frameworks used in Invasion Science’. The workshop led to a NeoBiota special issue on this theme, and includes a review by FABI researchers and international colleagues, exploring frameworks in the context of forest pathology.

A doctoral study in FABI confirms for the first time the presence of Xylosandrus crassiusculus, a polyphagous ambrosia beetle and its fungal symbiont, Ambroseilla roeperi, in three provinces in South Africa. The authors warn that this beetle species could be a threat to native and plantation trees.

A review on invasive gall-forming wasps that threaten non-native Eucalyptus plantations by researchers in the TPCP appears in Agricultural and Forest Entomology. They profile several species of likely Australian origin that have established on non-native Eucalyptus plantations globally and discuss various challenges to their management.

A study in the TPCP confirms the identity of seven novel fungal species associated with Dendroctonus valens, the red turpentine beetle. The study follows on surveys on the fungal associates of the beetle in China and North America. Results from this work appear in Persoonia.

A postdoctoral study in the TPCP describes two novel Huntiella species in the African clade, bringing the number of known species in the genus to 31. Though closely related, the two species display different mating systems. Outcomes from this study appear in the journal MycoKeys.

A review of the invasion history and global management strategies of Eucalyptus snout beetles in the Gonipterus scutellatus species complex by researchers in the TPCP appears in the Journal of Pest Science.

In a collaborative venture with Dr Jos Houbraken (Westerdijk Fungal Biodiversity Institute, the Netherlands), Prof. Cobus M Visagie, Dr Neriman Yilmaz (both from FABI) and others have recently completed and published a major study updating the taxonomy of the Eurotiales.

A study in the Forest Molecular Genetics (FMG) Programme at FABI interrogates the benefits of implementing genomic selection for growth and wood quality traits in an established Eucalyptus grandis breeding programme in South Africa. Outcomes from this study appear in an article.

The first study on alternative weed and cultivated hosts of Spongospora subterraneaf. sp. subterranea (Sss), in southern Africa identifies two species as ideal trap crops for rotation with potatoes. The study also introduces three new families to the known hosts of Sss in the region.

A consortium of microbiologists from around the globe, FABI included, is pushing for an overhaul in how scientific names are assigned to uncultivated bacteria and archaea. Despite their ecological, agricultural and medical importance, these organisms traditionally have not been recognized by the international body governing the nomenclature of prokaryotes.

Professor Cobus Visagie is a researcher in the Applied Mycology group at FABI. One of the group’s research goals is to discover fungal diversity in South Africa, and Cobus’ research is strongly focussed on the economically important genera Aspergillus, Penicillium and Talaromyces.

Postdoctoral research by Dr Norman Muzhinji in the Potato Pathology Programme at the Forestry and Agricultural Biotechnology Institute (FABI) sheds light on the genetic structure and diversity of Spongospora subterranea f. sp. subterranea in four potato-growing regions in South Africa, providing valuable insights on its management.

An MSc study by Kira Lynn in the RGE-FABI Tree Health Programme at the University of Pretoria has described a new Fusarium species, Fusarium rekanum sp. nov., associated with Euwallacea perbrevis, an ambrosia beetle species infesting Acacia crassicarpa plantations in Riau, Indonesia.

FABI postdoctoral Fellow Dr Andi Wilson has established a CRISPR-Cas9-based genome editing protocol for use in Huntiella omanensis, a tree-inhabiting fungus belonging to the Ceratocystidaceae family.

Research undertaken as part of a PhD study by Molly Malefo at the University of Pretoria’s Department of Plant and Soil Sciences and Forestry and Agricultural Biotechnology Institute sheds more light on the role of protease inhibitors in plants under drought stress.

The South African National Biodiversity Institute (SANBI) has funded a postdoctoral research project dedicated to monitoring plant health in botanical gardens and arboreta across South Africa. Two postdoctoral Fellows at the University of Pretoria’s Forestry and Agricultural Biotechnology Institute have held these fellowships.

The first comprehensive study mapping the distribution and genetic diversity of invasive Eucalyptus insect pests in sub-Saharan Africa confirms the presence of five major foliage-feeding species in 14 countries. The results of this study have implications on the quarantine, future research and management of these pests on the continent and beyond.

Dr Joey Hulbert broke new ground when he became the first candidate at the Forestry and Agricultural Biotechnology Institute to complete a PhD study incorporating citizen science. Citizen science is an approach that involves members of the public as active participants in scientific research.

FABI technology unravels the genetics behind fungal genome evolution The RIPper is a bioinformatics tool for the for quantifying genome-wide RIP mutations in fungal genomes. The strength of this software lies in the automation of laborious techniques to study the mutation process called Repeat-Induced Point mutations (RIP). The RIPper applies these technique

With the increased availability in genome data, inferences regarding evolutionary relationships among taxa can now be performed on a genome-wide scale. But it is widely accepted that not all parts of such massive datasets support the same evolutionary hypothesis. Because of this, a group of researchers at FABI recently investigated the effect of this.

The use of genome data to characterize species and elucidate relationships, particularly between problematic taxa, has become routine practice in bacteria. Recently, researchers from FABI joined in an international effort to describe two novel genera and characterize these within the larger context of the important bacterial group Burkholderia.

A PhD student in FABI, Runlei Chang, has discovered and described 19 new fungal species from China as part of the research for his thesis. These fungi are all associated with conifer-infesting bark beetles and their mites and belong to well-known genera such as Ophiostoma and Leptographium.

Two research papers from FABI were selected as cover stories in two consecutive issues of the international journal, Plant Pathology. The journal is published by Wiley for the British Society of Plant Pathology.

Plastids play an integral role in wood formation, and yet they are routinely ignored in the study of xylogenesis in forest trees. Desre Pinard and Dr Eshchar Mizrachi have published a review highlighting the unique biology of plastids in wood, suggesting that a new type of plastid, the xylopast, exists.

Approaches for characterizing metabolic potential from genomic sequences have previously been predicted to be useful in the description of bacterial taxa. Dr Marike Palmer, has recently employed these approaches for identifying biological processes contributing to the divergence of bacteria with a variety of lifestyles.

Comparative genomics is shaping our notion of what fungal species are. Based on current data, these unique evolutionary units are separated from one another by boundaries that are porous under certain conditions. This affects our expectations regarding their population biology and evolution, and our strategies for recognizing and controlling them.

The Polyphagous Shot Hole Borer is an ambrosia beetle native to Southeast Asia. In 2017 this pest was detected in South Africa. Its presence has since been confirmed in all provinces except Limpopo. The beetle has a symbiotic relationship with the fungus Fusarium euwallaceae, which causes branch die-back and death of susceptible trees.

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Phytophthora root rot (PRR) is the most severe and damaging disease in avocado plantations in South Africa. The causal agent of PRR is the notorious oomycete, Phytophthora cinnamomi (Pc). This pathogen has an extensive host range making it an economically important plant pathogen. The pathogen is a heterothallic species that can reproduce by sexual or asexual means. Furthermore, Pc is hemibiotrophic, meaning it has an initial biotrophic stage prior to switching to the nectrophic stage at later stages of infection. It can persist in soil or infected plant material for extended periods of time, and there is no means to eradicate this oomycete from infected areas once the pathogen has successfully established in soils. Currently, phosphite injections, along with the use of good agricultural practices, are commonly used as methods of control for PRR.

Research within the ARP has provided some insight into the biology, population diversity and the molecular basis for the Pc-avocado interaction. The sequencing of the genome of a South African Pc isolate and the availability of RNA sequencing data from a Pc-avocado infection trial has allowed the group to delve further into understanding how the pathogen is able to manipulate and suppress plant immunity during infection. Current work in the ARP involves identifying and functionally characterising effector genes which are known to play roles during infection. The group is currently on three groups of effectors; the NLPs, RxLRs and Crinklers; and the aim is to determine how these effectors contribute to the pathogenicity of this pathogen and the strategies by which they are able to manipulate or suppress plant immunity to establish infection.

* Read more about Phytophthora cinnamomi on our Fact sheet here.

ARP Team Members

Katelyn Baird: Characterising the role of Phytophthora cinnamomi NLP proteins in plant cell infection.

Ncobile Kunene: Elucidating the role of Phytophthora cinnamomi RxLR effector genes during Persea americana infection.

Kayla Midgley: Characterising the role of Phytophthora cinnamomi CRN effector proteins in host plant cell death.

Susanna Anbu: Expression profiling of Nep-like protein (NLP) effector genes during infection in avocado.

Workshops & Symposia

Archive

The 35<sup>th</sup> Annual Meeting of the Tree Protection Co-operative Programme (TPCP) and DSI-NRF Centre of Excellence in Plant Health Biotechnology (CPHB)

The 35^th Annual Meeting of the Tree Protection Co-operative Programme

New Publications

Marais I, Buitendag C, Duong TA, Crampton BG, Theron J, Kidanemarium D, Berger DK. (2024) Double-stranded RNA uptake for the control of the maize pathogen Cercospora zeina. Plant Pathology Online first:1-11. 10.1111/ppa.13909

van Heerden A, Pham NQ, Wingfield BD, Wingfield MJ, Muro Abad JI, Durán A, Wilken PM. (2024) LAMP assay to detect Elsinoë necatrix; an important Eucalyptus shoot and leaf pathogen. Plant Disease 10.1094/PDIS-01-24-0086-RE

Silva GA, Oliveira MES, Rêgo GMS, Wingfield BD, Wingfield MJ, Ferreira MA. (2024) Chrysoporthe brasiliensis sp. nov. pathogenic to Melastomataceae in southeast Brazil. Fungal Biology 10.1016/j.funbio.2024.04.001

Fick A, Swart V, Bombarely A, van den Berg N. (2024) Comparative transcriptional analysis of Persea americana MYB, WRKY and AP2/ERF transcription factors following Phytophthora cinnamomi infection. Molecular Plant Pathology 25(4):e13453. 10.1111/mpp.13453

Van Lill M, Venter SN, Muema EK, Palmer M., Beukes CW, Chan WY, Steenkamp ET. (2024) SeqCode facilitates naming of South African rhizobia left in limbo. Systematics and Applied Microbiology 47(2-3):126504. 10.1016/j.syapm.2024.126504

Visagie CM, Meyer H, Yilmaz N. (2024) Maize–Fusarium associations and their mycotoxins: Insights from South Africa. Fungal Biology 10.1016/j.funbio.2024.03.009

Elisa P, Allison J, Hurley BP, Slippers B, Fourie G. (2024) Lethal and sublethal effects of insecticides on Bathycoelia distincta (Heteroptera: Pentatomidae). African Entomology 32: e16992:1-9. 10.17159/2254-8854/2024/a16992

Pietersen G, Morgan S, Read DA. (2024) First report of Citrus concave gum-associated virus (CCGaV) on apple (Malus spp.) in South Africa. Journal of Plant Pathology 10.1007/s42161-024-01629-9

Gush S, Lebre P, Coutinho TA, Cowan DA, van der Waals JE. (2024) Disentangling shifts in the soil microbiome of potatoes infected with Rhizoctonia solani Anastomosis Group 3-PT in search of potential biocontrol agents. Phytobiomes Journal 10.1094/PBIOMES-06-23-0046-R

Dankie VN, Steenkamp ET, De Vos L, Swalarsk-Parry BS, Dewing C, Fru F, Wilken PM, Mchunu NP, Wingfield BD, Wingfield MJ, van der Nest MA. (2024) Growth, pathogenicity and sexual fertility of the African tree pathogen Ceratocystis albifundus. Journal of Plant Pathology :1-11. 10.1007/s42161-024-01634-y

Abkallo HM, Arbuthnot P, Auer TO, Berger DK, Burger J, Chakauya E, Concordet J-P, Diabate A, Di Donato V, Groenewald J-H, Guindo A, Koekemoer LL, Nazare F, Nolan T, Okumu F, Orefuwa E, Paemka L, Prieto-Godino L, Runo S, Sadler M, Tesfaye K, Tripathi L, Wondji C. (2024) Making genome editing a success story in Africa. Nature Biotechnology :1-4. https://rdcu.be/dBJUa

Robert R, Robberste N, Thompson GD, Read DA. (2024) Characterization of macadamia ringspot‑associated virus, a novel Orthotospovirus associated with Macadamia integrifolia in South Africa. European Journal of Plant Pathology 10.1007/s10658-024-02832-1

Hiroyuki S, Marincowitz S, Roux J, Paap T, Wingfield BD, Wingfield MJ. (2024) A new genus and species of Cryphonectriaceae causing stem cankers on plantation eucalypts in South Africa. Plant Pathology :1-14. 10.1111/ppa.13883

Strydom RF, Wilson CR, Tegg RS, Balendres MA, van der Waals JE. (2024) Advancements in Spongospora subterranea: Current knnowledge, management strategies, and research gaps. Potato Research 10.1007/s11540-024-09701-8

Mapfumo P, Buthelezi S, Archer E, Swanevelder DZH, Wilken PM, Creux N. (2024) In-field climatic factors driving Sclerotinia head rot progression across different sunflower planting dates. Plant Pathology 10.1111/ppa.13873

Price J-L, Visagie CM, Meyer H, Yilmaz N. (2024) Fungal species and mycotoxins Associated with Maize ear rots collected from the Eastern Cape in South Africa. Toxins 16:95. 10.3390/toxins16020095

Tarigan M, Wingfield MJ, Jami F, Marpaung YMAN, Duran A, Pham NQ. (2024) Pathogenicity of Chrysoporthe deuterocubensis on eucalypts in Indonesia. Southern Forests: a Journal of Forest Science 10.2989/20702620.2023.2279054

Caballol M, Serradó F, Barnes I, Camarero JJ, Valeriano C, Colangelo M, Oliva J. (2024) Climate, host ontogeny and pathogen structural specificity determine forest disease distribution at a regional scale. Ecography :e06974. 10.1111/ecog.06974

MISEV Consortium, Motaung T. (2024) Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches. Journal of Extracellular Vesicles 13(2):e12404. 10.1002/jev2.12404

Pham NQ, Suzuki H, Duong TA, Wingfield BD, Barnes I, Duran A, Wingfield MJ. (2024) Cryptic sexual reproduction in an emerging Eucalyptus shoot and foliar pathogen. Plant Pathology 10.1111/ppa.13876

Francinah M. Ratsoma, Nthabiseng Z. Mokoena, Quentin C. Santana, Brenda D. Wingfield, Emma T. Steenkamp, Thabiso E. Motaung. (2024) Characterization of the Fusarium circinatum biofilm environmental response role. Journal of Basic Microbiology 00(00):1-16. 10.1002/jobm.202300536

Morrison EW, Duong TA, Garnas JR. (2024) A high-quality draft genome sequence of Neonectria faginata, causative agent of beech bark disease of Fagus grandifolia. Microbiology Resource Announcements 10.1128/mra.01048-23

Roberts E, Paap T, Roets F. (2024) Chemical control of the Polyphagous Shothole Borer beetle (PSHB, Euwallacea fornicatus) and Fusarium euwallaceae in American sweetgum (Liquidambar styraciflua). Journal of Plant Pathology 10.1007/s42161-023-01583-y

Fitza KNE, Allison J, Slippers B, Chingandu N, Reed SE. (2024) Diversity and potential sources of introduction of the Beech leaf nematode (Litylenchus crenatae< mccannii) to Ontario, Canada. Canadian Journal of Plant Pathology

Engelbrecht K, Raubenheimer I, Paap T, Neethling E, Roets F. (2024) Detection of Fusarium euwallaceae and its vector Euwallacea fornicatus on Pear (Pyrus communis) and in deciduous fruit orchards in South Africa. Australasian Plant Disease Notes 19(1) 10.1007/s13314-023-00524-z

Visagie CM, Meijer M, Kraak B, Groenewald M, Houbraken J, Theelen B, Vorst Y, Boekhout T. (2024) Blastobotrys nigripullensis, a new yeast species isolated from a fungal outbreak on an ancient Roman shipwreck in the Netherlands. Antonie Van Leeuwenhoek 117:22. 10.1007/s10482-023-01898-x

Hlongwane NL, Dzomba EF, Hadebe K, van der Nest MA, Pierneef R, Muchadeyi FC. (2024) Identification of signatures of positive selection that have shaped the genomic landscape of South African pig populations. Animals 14:235. 10.3390/ani14020236

De Vos L, van der Nest MA, Santana QC, van Wyk S, Leeuwendaal KS, Wingfield BD, Steenkamp ET. (2024) Chromosome-level assemblies for the pine pitch canker pathogen Fusarium circinatum. Pathogens 13(1):70. 10.3390/pathogens13010070

Chen BY, Wu WX, Chen SF. (2024) Wide distribution of Teratosphaeria epicoccoides and T. destructans associated with diseased Eucalyptus leaves in plantations in Southern China. Microorganisms 12:129. 10.3390/microorganisms12010129

Visagie CM, Yilmaz N, Kocsubé S, Frisvad JC, Hubka V, Samson RA, Houbraken J. (2024) A review of recently introduced Aspergillus, Penicillium, Talaromyces and other Eurotiales species. Studies in Mycology 107:1–66. 10.3114/sim.2024.107.01

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