Functional characterization of a novel effector of a necrotrophic fungal phytopathogen Ascochyta rabiei
P. VERMA (1), S. Verma (1), S. Singh (1), K. Singh (1), S. Purayannur (1), K. Kumar (1) (1) National Institute of Plant Genome Research, India

The necrotrophic fungal phytopathogens are responsible for major crop losses worldwide. However, the mechanisms responsible for the necrotrophic behaviour of these fungi are still not well understood. Not much study has been done for necrotrophic effectors and a few effector proteins have been characterized till date. Ascochyta rabiei is a necrotrophic fungus belonging to ascomycetes. It is an important pathogen of chickpea and sometimes cause upto 100% yield loss. The A. rabiei-chickpea system provides an excellent model for studying the mechanisms involved in pathogenesis of such fungi. We have performed genome sequencing and extensive genome and secretome analyses of A. rabiei. Several analyses were carried out that manifest the necrotrophic lifestyle of A. rabiei. In 34.6 Mb draft genome of A. rabiei, we predicted 10,596 protein-coding genes and 758 secretory proteins with different conserved motifs. We further characterized a novel effector candidate, PEC25, which is highly conserved in diverse fungi including animal pathogens. Its homologs have not been characterized in any filamentous fungi yet. Functional analyses revealed that PEC25 is requisite for A. rabiei virulence. During pathogen infection, PEC25 translocates into the host cell nucleus, which is critical for its function. Interaction analysis showed the possible host target of PEC25, which is promoting novel functions. Detailed transcriptome analysis of chickpea following infection with PEC25 knockout strain revealed new sets of genes involved in susceptibility. This study advocates the role of effectors in the establishment of disease by necrotrophic fungi.

Abstract Number: P9-335
Session Type: Poster