Host-Induced Gene Silencing of an Adenylate Kinase Gene Involved in Fungal Energy Metabolism Improves Plant Resistance to Verticillium dahliae

Abstract

Verticillium wilt, caused by the ascomycete fungus <i>Verticillium dahliae</i> (<i>Vd</i>), is a devastating disease of numerous plant species. However, the pathogenicity/virulence-related genes in this fungus, which may be potential targets for improving plant resistance, remain poorly elucidated. For the study of these genes in <i>Vd</i>, we used a well-established host-induced gene silencing (HIGS) approach and identified 16 candidate genes, including a putative adenylate kinase gene (<i>VdAK</i>). Transiently <i>VdAK</i>-silenced plants developed milder wilt symptoms than control plants did. <i>VdAK</i>-knockout mutants were more sensitive to abiotic stresses and had reduced germination and virulence on host plants. Transgenic <i>Nicotiana benthamiana</i> and <i>Arabidopsis thaliana</i> plants that overexpressed <i>VdAK</i> dsRNAs had improved <i>Vd</i> resistance than the wild-type. RT-qPCR results showed that <i>VdAK</i> was also crucial for energy metabolism. Importantly, in an analysis of total small RNAs from <i>Vd</i> strains isolated from the transgenic plants, a small interfering RNA (siRNA) targeting <i>VdAK</i> was identified in transgenic <i>N. benthamiana</i>. Our results demonstrate that HIGS is a promising strategy for efficiently screening pathogenicity/virulence-related genes of <i>Vd</i> and that <i>VdAK</i> is a potential target to control this fungus.