Forest tree species such as Eucalyptus and Pine are subjected to attack by various pests and pathogens during their life-time. Examples are the insect pest, Leptocybe invasa, the stem canker pathogen, Chrysoporthe austroafricana, the root rot pathogen, Phytophthora cinnamomi, and the pitch canker pathogen Fusarium circinatum. Disease incidence is exacerbated by climate change, which is predicted to make environments more favorable for pathogens and pests. "Host-jumping" from native hosts to forest plantations has been reported. Such threats are especially severe for clonally propagated tree species such as Eucalyptus as entire plantations could be lost due to susceptibility of a particular clone. Thus genotypes with improved resistance or tolerance are necessary as part of an integrated management strategy to curb losses due to pests and pathogens. It is with this vision that the Eucalyptus and Pine Pathogen Interactions programme was initiated. The research in our programme is aimed at understanding the plant defence mechanisms that exist in Eucalyptus and Pine trees which may be harnessed to improve its resistance capacity in future. We are currently dissecting the Eucalyptus defensome (or defence transcriptome) based on the recently released genome sequence of Eucalyptus grandis, coupled with data from high-throughput transcriptome technologies.

Collaboration:

  • Tree Pathology Co-operative Programme
  • Sappi and Mondi

On-going projects:

Projects undertaken by EPPI aim to (i) ascertain the molecular basis of disease responses in Eucalyptus to a canker pathogen Chrysoporthe austroafricana (ii) determine the molecular defence mechanisms of E. grandis against the gall wasp Leptocybe invasa and (iii) determine the effectiveness of induced resistance in Pinus patula against Fusarium circinatum. These pathosystems provide the biological platform to address key questions such as: "What is the molecular basis of tolerance and susceptibility?", "What are the signature defence responses to different types of pests and pathogens?", "What are the convergent defence responses in the host?" and "Which regulatory sequences and defence genes could be targeted for enhancing defence in the host?". This would provide a basis to implement biotechnology strategies to develop resistant families (seedling forestry) or clones (clonal forestry) in future.

New Publications

Naidoo S, Slippers B, Plett JM, Coles D, Oates CN. (2019) The road to resistance in forest trees. Frontiers in Plant Science 10:273. 10.3389/fpls.2019.00273
Backer R, Naidoo S, van den Berg N. (2019) The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1) and Related Family: Mechanistic Insights in Plant Disease Resistance. Frontiers in Plant Science 10:102. 10.3389/fpls.2019.00102
McTaggart AR, Duong TA, Le VQ, Shuey LS, Smidt W, Naidoo S, Wingfield MJ, Wingfield BD. (2018) Chromium sequencing: the doors open for genomics of obligate plant pathogens. BioTechniques 65(5):253-257. 10.2144/btn-2018-0019
Naidoo S, Christie N, Acosta JJ, Mphahlele MM, Payn KG, Myburg AA, Külheim C. (2018) Terpenes associated with resistance against the gall wasp, Leptocybe invasa, in Eucalyptus grandis. Plant, Cell & Environment 41(8):1840-1851. 10.1111/pce.13323
McTaggart AR, Shuey LS, Granados GM, du Plessis E, Fraser S, Barnes I, Naidoo S, Wingfield MJ, Roux J. (2018) Evidence that Austropuccinia psidii may complete its sexual life cycle on Myrtaceae. Plant Pathology 67:729-734. 10.1111/ppa.12763
Zwart L, Berger DK, Moleleki LN, Van der Merwe NA, Myburg AA, Naidoo S. (2017) Evidence for salicylic acid signalling and histological changes in the defence response of Eucalyptus grandis to Chrysoporthe austroafricana. Scientific Reports 7:45402. 10.1038/srep45402 PDF
Tobias PA, Christie N, Naidoo S, Guest DI, Külheim C. (2017) Identification of the Eucalyptus grandis chitinase gene family and expression characterization under different biotic stress challenges. Tree Physiology 37(5):565-582. 10.1093/treephys/tpx010
Marsberg A, Kemler M, Jami F, Nagel JH, Postma-Smidt A, Naidoo S, Wingfield MJ, Crous PW, Spatafora J, Hesse CN, Robbertse B, Slippers B. (2017) Botryosphaeria dothidea: A latent pathogen of global importance to woody plant health. Molecular Plant Pathology 18:477–488. 10.1111/mpp.12495
Oates CN, Denby KJ, Myburg AA, Slippers B, Naidoo S. (2016) Insect gallers and their plant hosts: From omics data to systems biology. International Journal of Molecular Sciences 17(11):1891. 10.3390/ijms17111891 PDF
Roux J, Granados GM, Shuey L, Barnes I, Wingfield MJ, McTaggart AR. (2016) A unique genotype of the rust pathogen, Puccinia psidii, on Myrtaceae in South Africa. Australasian Plant Pathology 45:645-652. 10.1007/s13313-016-0447-y
Kanzi AM, Wingfield BD, Steenkamp ET, Naidoo S, Van der Merwe NA. (2016) Intron derived size polymorphism in the mitochondrial genomes of closely related Chrysoporthe species. PLOS ONE 11(6):e0156104. 10.1371/journal.pone.0156104
Oelofse D, Gazendam I, Veale A, Djami-Tchatchou A, Berger D, Dubery I. (2016) Functional characterization of a defense-related class-III chitinase promoter from Lupinus albus, active in legume and monocot tissues. European Journal of Plant Pathology 146(4):923-936. 10.1007/s10658-016-0970-2
McTaggart AR, van der Nest MA, Steenkamp ET, Roux J, Slippers B, Shuey LS, Wingfield MJ, Drenth A. (2016) Fungal Genomics Challenges the Dogma of Name-Based Biosecurity. PLoS Pathogens 12(5):e1005475. 10.1371/journal.ppat.1005475 PDF
Meyer FE, Shuey LS, Ramsuchit S, Mamni T, Berger DK, van den Berg N, Myburg AA, Naidoo S. (2016) Dual RNA-sequencing of Eucalyptus nitens during Phytophthora cinnamomi challenge reveals pathogen and host factors influencing compatibility. Frontiers in Plant Science 7:191. 10.3389/fpls.2016.00191 PDF
Kwenda S, Gorshkov V, Ramesh AM, Naidoo S, Rubagotti E, Birch PRJ, Moleleki LN. (2016) Discovery and profiling of small RNAs responsive to stress conditions in the plant pathogen Pectobacterium atrosepticum. BMC Genomics 17(1) 10.1186/s12864-016-2376-0
Onkendi EM, Ramesh AM, Kwenda S, Naidoo S, Moleleki LN. (2016) Draft Genome Sequence of a Virulent Pectobacterium carotovorum subsp. brasiliense Isolate Causing Soft Rot of Cucumber. Genome Announcements 4(1) 10.1128/genomeA.01530-15 PDF
Ronishree Magwanda, Lizahn Zwart, Nicolaas A. van der Merwe, Lucy Moleleki, Dave Kenneth Berger, Alexander A. Myburg, Sanushka Naidoo. (2016) Localization and Transcriptional Responses of Chrysoporthe austroafricana in Eucalyptus grandis Identify Putative Pathogenicity Factors. Front. Microbiol. 10.3389/fmicb.2016.01953
Christie N, Tobias P, Naidoo S, Guest D, Külheim C. (2016) The Eucalyptus grandis NBS-LRR Gene Family: Physical Clustering and Expression Hotspots. Frontiers in Plant Science 6(1238)
Visser EA, Wegrzyn JL, Steenkamp ET, Myburg AA, Naidoo S. (2015) Combined de novo and genome guided assembly and annotation of the Pinus patula juvenile shoot transcriptome. BMC Genomics 16:1057. 10.1186/s12864-015-2277-7 PDF
Oates CN, Külheim C, Myburg AA, Slippers B, Naidoo S. (2015) The transcriptome and terpene profile of Eucalyptus grandis reveals mechanisms of defence against the insect pest, Leptocybe invasa. Plant & Cell Physiology 56(7):1418-1428. 10.1093/pcp/pcv064