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Research Features

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.

 

 

New Publications

Tarigan M, Wingfield MJ, Jami F, Oliveira LSS, Saha MA, Durán A, Pham NQ. (2025) Pathogenicity of Pythium myriotylum on Acacia crassicarpa and Acacia mangium × Acacia auriculiformis clones in Indonesia. Southern Forests: a Journal of Forest Science 87:1–5. 10.2989/20702620.2024.2432863
Muema EK, van Lill M, Venter SN, Claassens R, Steenkamp ET. (2025) Mesorhizobium salmacidum sp. nov. and Mesorhizobium argentiipisi sp. nov. are symbionts of the dry-land forage legumes Lessertia diffusa and Calobota sericea. Antonie van Leeuwenhoek 19(3):1-20. 10.1007/s10482-025-02063-2
Motaung TE, Ratsoma FM, Kunene S, Santana QC, Steenkamp ET, Wingfield BD. (2025) Harnessing exogenous membrane vesicles for studying Fusarium circinatum and its biofilm communities. Microbial Pathogenesis 10.1016/j.micpath.2025.107368
van Dijk A, Wilson AM, Marx B, Hough B, Swalarsk-Parry BS, De Vos L, Wingfield MJ, Wingfield BD, Steenkamp ET. (2025) CRISPR-Cas9 genome editing reveals that the Pgs gene of Fusarium circinatum is involved in pathogenicity, growth and sporulation.. Fungal Genetics and Biology 10.1016/j.fgb.2025.103970
Balocchi F, Wingfield MJ, Paap T. (2025) First record of the white root rot fungus Dematophora necatrix on indigenous South African trees. Journal of Plant Pathology 10.1007/s42161-025-01861-x PDF
Coelho MA, David-Palma M, Aylward J, Pham NQ, Visagie CM, Fuchs T, Yilmaz N, Roets F, Sun S, Taylor JT, Wingfield BD, Fisher MC, Wingfield MJ, Heitman J. (2025) Decoding Cryptococcus: From African biodiversity to worldwide prevalence. PLOS Pathogens 21:e1012876. 10.1371/journal.ppat.1012876
Solís M, Hammerbacher A, Wingfield M.J, Naidoo S. (2025) Enhancing plantation forest sustainability: A review of Eucalyptus defence mechanisms to foliar fungal pathogens. Current Forestry Reports 10.1007/s40725-024-00243-3
Ratsoma MF, Santana QC, Wingfield BD, Steenkamp ET, Motaung TE. (2025) Understanding cargo sorting and interactive effects of membrane vesicles in fungal phytopathogens: Current knowledge and research gaps. Fungal Biology Reviews 51 10.1016/j.fbr.2025.100411
Harvey A, van den Berg N, Swart V. (2025) In silico characterisation of the avocado WAK/WAKL gene family with a focus on genes involved in defence against Phytophthora cinnamomi. Frontiers in Plant Science 15:1474781. 10.3389/fpls.2024.1474781 PDF
Botes J, Ma X, Chang J, Van de Peer Y, Berger DK. (2025) Flavonoids and anthocyanins in seagrasses: implications for climate change adaptation and resilience. Frontiers in Plant Science 15(1520474):1-17. 10.3389/fpls.2024.1520474
Wondafrash M, Wingfield MJ, Hurley BP, Slippers B, Mutitu EK, Jenya H, Paap T. (2025) DNA sequence data confirms the presence of two closely related cypress-feeding aphid species on African cypress (Widdringtonia spp.) in South Africa. Southern Forests 86:278-285. 10.2989/20702620.2024.2390863 PDF
Mangani R, Mazarura J, Matlou S, Marquart A, Archer E, Creux N. (2025) The impact of past and current district-level climatic shifts on maize production and the implications for South African farmers. Theoretical and Applied Climatology 156:109. 10.1007/s00704-024-05334-6
Möller H, Slippers B, van den Berg N. (2025) Branch canker battles: understanding and managing the Botryosphaeriaceae in avocado. Phytoparasitica 53(17) 10.1007/s12600-024-01227-6
Pham NQ, Wingfield BD, Barnes I, Gazis R, Wingfield MJ. (2025) Elsinoe species: The rise of scab diseases. Plant Pathology 10.1111/ppa.14015
Theron E, van Niekerk JM, van der Waals JE. (2025) A review of the use of phosphonates in the management of Phytophthora nicotianae in citrus in South Africa. Phytoparasitica 53(11) 10.1007/s12600-024-01234-7 PDF
Aylward J, Atkins S, Roets F, Wingfield BD, Wingfield MJ. (2025) Several Seiridium species (Sporocadaceae: Xylariales) cause cypress canker in South Africa. Fungal Biology 129:101528. 10.1016/j.funbio.2024.101528
Martin G, Canavan K, Chikowore G, Bugan R, De Lange W, du Toit B, Harding G, Heath R, Hill M, Hurley BP, Ivey P, Muir D, Musedeli J, Richardson DM, Slippers B, Stafford L, Turner A, Watson K, van Wilgen BW. (2025) Managing wilding pines in the Cape Floristic Region, South Africa: Progress and prospects. South African Journal of Botany 177:377-391. 10.1016/j.sajb.2024.12.011 PDF
Wingfield MJ, Slippers B, Barnes I, Duong AT, Wingfield BD. (2025) The Pine pathogen Diplodia sapinea: Expanding frontiers. Current Forestry Reports 11(2) 10.1007/s40725-024-00236-2
Mangani R, Archer E, Engelbrecht C, Bellochi G, Mukiibi A, Creux N. 2025. The Impact of Climate Change on Crop Production and Food Security: A South African Perspective. In: Climate Change, Food Security, and Land Management. Leal Filho W, Matandirotya N, Yayeh Ayal D, Luetz JM, Borsari B. (eds). Springer, Cham, Switzerland, pp 1-12.
Ashmore JS, Slippers B, Duong TA, Dittrich-Schröder G. (2024) Understanding the genetics of sex determination in insects and its relevance to genetic pest management. Insect Molecular Biology 10.1111/imb.12982