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

Xiaofeng Su,Guoqing Lu,Latifur Rehman,Guoqing Sun,Wende Liu,Huiming Guo,Xiaokang Li,Guoliang Wang,Hongmei Cheng

doi:10.3390/biom10010127

Abstract

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

Highlights

Verticillium dahliae (Vd), the causal agent of Verticillium wilt (Vw), is a destructive fungal pathogen infecting over 400 plant species, including important ornamental, horticultural, agronomical, and woody plants [1]
To identify the pathogenicity factor genes that are required for Vd virulence, we employed a well-established virus-guided host-induced gene silencing (HIGS) system [45]
Based on SwissProt and Blast results, these genes were divided into cellular components, molecular functions, and biological processes; 92 fungal genes involved in diverse biological processes were considered as candidates for HIGS in N. benthamiana system (Table S1)

Summary

Introduction

Verticillium dahliae (Vd), the causal agent of Verticillium wilt (Vw), is a destructive fungal pathogen infecting over 400 plant species, including important ornamental, horticultural, agronomical, and woody plants [1]. Symptoms are not uniform among different plant species [2], and in general, the fungus is difficult to control because it survives in the plant vascular system and infects the hosts via infested soil and diseased plant debris [3]. Considerable studies on Vw and the associated fungi and the public release of the genomic sequence of Vd and its sister fungus V. alfalfae, have enabled the identification of candidate pathogenicity and virulence genes [6,7,8]. Multiple genes playing a role in signal pathways, development, and nutrition have been reported [17,18,19,20], few have been confirmed as feasible candidates for the control of Vd in plants

Methods

Results

Conclusion