Understanding genetic variation in grapevine diseases and the genetic basis for pesticide resistance
Grapevine diseases that are caused by fungal/oomycete pathogens such as Botrytis and powdery and downy mildews are responsible for significant crop losses. Current control measures rely on spraying with agrochemicals; however, there is growing evidence for resistance of fungal/oomycete pathogens to specific fungicides. By determining the genetic basis of these resistant phenotypes, DNA diagnostics to efficiently test for potential resistance prior to choosing an agrochemical will be developed and compared to established slow and complicated assays. This will provide impartial data to inform agrochemical purchasing and spray decisions, and potentially guide the development of next-generation agrochemicals.
Mapping resistance alleles in grapevine powdery mildew
Next generation sequencing has been applied to investigate the prevalence of genetic variants associated with fungicide resistance in powdery mildew from four hundred individual population samples across four vineyards (two vineyards sampled in 2013/2014 and two vineyards sampled in 2014/2015). Initial results show that the specific genetic variants at the cyp51 locus that correlate with high levels of azole resistance were readily detected and quantified in the majority of the populations tested. Azoles are a group of fungicides commonly used to control powdery mildew in vineyards. Further work is now needed to associate the prevalence of these genetic markers with the potential for loss of field efficacy.