Abstract
Cercospora beticola, causal agent of Cercospora leaf spot (CLS), is the most prominent foliar disease of sugarbeet. The infection caused by C. beticola can significantly deteriorate sugarbeet foliar tissue leading to severe yield losses. Despite being a pathogen of high economic importance, very limited information is available regarding the molecular mechanisms deployed by C. beticola to manipulate the sugarbeet host. Recently, we sequenced a large globally diverse population of C. beticola to identify effector genes that are conserved among the species and leveraged RNAseq data to select potential effectors that were transcriptionally active during the biotrophic phase of C. beticola infection. Candidate effectors were transiently expressed in Nicotiana benthamiana using to screen for cell death inducing activity. Majority of the selected candidate did not induce any cell death inducing phenotype in N. benthamiana leaves however four effectors demonstrated cell death suppression activity. Effectors suppressing cell death were also able to suppress the production of reactive oxygen species (ROS) induced due to host defense pathways activation. Further, In planta localization studies of fluorescently tagged candidates highlighted chloroplast to their potential target site. The current study provides a framework for understanding the function of C. beticola biotrophic effectors and their role in plant defense manipulation.