Fungal F8-Culture Filtrate Induces Tomato Resistance against Tomato Yellow Leaf Curl Thailand Virus

Yi-Shu Chiu,Hsin-Hung Yeh,Chi-Wei Tsai,Yuh Tzean,Yi-Hui Chen

doi:10.3390/v13081434

Abstract

Tomato (Solanum lycopersicum) is an important economic crop worldwide. However, tomato production is jeopardized by the devastating tomato yellow leaf curl disease caused by whitefly-transmitted begomoviruses (WTBs). In this study, we evaluated the efficacy of our previously developed plant antiviral immunity inducer, fungal F8-culture filtrate, on tomato to combat tomato yellow leaf curl Thailand virus (TYLCTHV), the predominant WTB in Taiwan. Our results indicated that F8-culture filtrate treatment induced strong resistance, did not reduce the growth of tomato, and induced prominent resistance against TYLCTHV both in the greenhouse and in the field. Among TYLCTHV-inoculated Yu-Nu tomato grown in the greenhouse, a greater percentage of plants treated with F8-culture filtrate (43–100%) were healthy-looking compared to the H2O control (0–14%). We found that TYLCTHV cannot move systemically only on the F8-culture filtrate pretreated healthy-looking plants. Tracking the expression of phytohormone-mediated immune maker genes revealed that F8-culture filtrate mainly induced salicylic acid-mediated plant immunity. Furthermore, callose depositions and the expression of the pathogen-induced callose synthase gene, POWDERY MILDEW RESISTANT 4 were only strongly induced by TYLCTHV on tomato pretreated with F8-culture filtrate. This study provides an effective way to induce tomato resistance against TYLCTHV.

Highlights

Tomato (Solanum lycopersicum) is an economically important vegetable crop, which ranks third in this class in terms of volume of production and first in terms of processing volume [1]
Our results indicated that F8-culture filtrate treatment in tomatoes induced strong resistance to tomato yellow leaf curl Thailand virus (TYLCTHV) both in the greenhouse and in the field
Yu-Nu tomato is a favorable tomato with commercial value; it is known for its susceptibility to several pathogens including whitefly-transmitted begomoviruses (WTBs)

Summary

Introduction

Tomato (Solanum lycopersicum) is an economically important vegetable crop, which ranks third in this class in terms of volume of production and first in terms of processing volume [1]. Tomato yellow leaf curl disease (TYLCD) caused by whitefly-transmitted begomoviruses (WTBs) has a devastating effect on tomato production worldwide [2,3,4,5]. One of the main approaches to managing TYLCD relies on controlling the whitefly vector using insecticide [6,7]. It has become increasingly difficult to control the whitefly vector population in this way because of the rapid evolution of whitefly’s resistance to insecticides [2,7,8]. Screening of TYLCD-resistant tomato cultivars revealed that most commercially cultivated tomato cultivars are susceptible to the disease [9]. As a large number of tomato cultivars are planted for commercial purposes, transferring the resistance loci to these various commercial tomato cultivars remains a challenge. Transgenic approaches that mainly use RNAi strategies have been successfully applied to plants to manage TYLCD infection with promising results [13,14,15,16,17,18,19,20,21,22,23,24]

Methods

Results

Conclusion