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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.

 

 

New Publications

Ramaswe JB, Steenkamp ET, De Vos L, Fru FF, Adegeye OO, Wingfield BD. (2024) Sex pheromone receptor Ste2 orchestrates chemotropic growth towards pine root extracts in the pitch canker pathogen Fusarium circinatum. Pathogens 13:425. 10.3390/pathogens13050425
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 PDF
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 PDF
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
Bornman S, Thomas C, Ntladi S, Wilken PM. (2024) Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot on peanut (groundnut) in South Africa. Australasian Plant Disease Notes 19 10.1007/s13314-024-00537-2
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 PDF
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 PDF
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 PDF