Identification and characterization of the Verticillium dahliae effector that is responsible for cotton defoliation

Plant pathogens from diverse taxonomic origins have been shown to secrete effector proteins into host plants to manipulate host physiology and establish infection. Verticillium dahliae is a soil-born fungus that causes Verticillium wilt disease in a wide range of crops, including cotton and olive. V. dahliae strains have previously been characterized as defoliating and non-defoliating strains based on their ability to cause defoliation on cotton, but the V. dahliae gene(s) that are involved in cotton defoliation remain unknown thus far. Here, we present a comparative genomics study defoliating and non-defoliating strains of V. dahliae that enabled us to identify a region of about 20 kb that specifically occurs in multiple defoliating strains. In this region, we were subsequently able to uncover a single highly-expressed gene that encodes a putative effector protein. Currently, we are performing experiments to confirm the role of this effector in cotton defoliation.