International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

Characterisation of small RNA mediated silencing in the Zymoseptoria tritici - wheat interaction


Graeme Kettles
Rothamsted Research
University of Birmingham

Bernhard Hofinger
Rothamsted Research

Pingsha Hu
Syngenta Biotechnology Inc., Research Triangle Park, NC, USA

Carlos Bayon
Rothamsted Research

Jason Rudd
Rothamsted Research

Dirk Balmer
Syngenta Crop Protection AG, Switzerland

Mikael Courbot
Syngenta Crop Protection AG, Switzerland

Kim Hammond-Kosack
Rothamsted Research

Gabriel Scalliet
Syngenta Crop Protection AG, Switzerland

Kostya Kanyuka*
Rothamsted Research


Poster Presentation
Host-Pathogen Interactions

Atrium, UCD O'Brien centre for Science
Poster 34

View this abstract online by visting isclb2019.com/see/ABS51286

Cross-kingdom small RNA mediated silencing (also known as RNA interference or RNAi) has recently been shown to occur in several plant-pathogen interactions. However, it remains unknown how universal this phenomenon is, and in particular whether RNAi facilitates colonization of plants by fungal pathogens that invade extracellular spaces and do not form specialized feeding structures or penetrate host cells either during entire life cycle or during prolonged initial phases of infection. One such pathogen is Zymoseptoria tritici, which causes Septoria tritici blotch - a serious foliar disease of wheat. In this study we defined the global small RNA (sRNA) populations in Z. tritici expressed in vitro as well at the several key time points during wheat colonisation, and computationally predicted their potential wheat mRNA targets. However, molecular approaches failed to validate targeting of selected wheat mRNAs by fungal sRNAs, and bioassays using newly generated Z. tritici mutant strains carrying DCL and AGO gene deletions suggested that these important components of RNAi are dispensable for full infection of wheat. Moreover, we demonstrated that Z. tritici is incapable of environmental dsRNA uptake, and neither in vitro nor in planta application of dsRNAs in a virus-mediated Host-induced gene silencing procedure was effective in preventing fungal growth or disease. Collectively, our data suggest that RNAi approaches for gene function analyses in Z. tritici and potentially also as a disease control measure may not be as effective as has been demonstrated for some other plant pathogenic fungi.