Inhibitory effect of Xenorhabdus nematophila TB on plant pathogens Phytophthora capsici and Botrytis cinerea in vitro and in planta.

Xiangling Fang,Manrang Zhang,Xing Zhang,Qian Tang,Yonghong Wang

doi:10.1038/srep04300

Abstract

Entomopathogenic bacteria Xenorhabdus spp. produce secondary metabolites with potential antimicrobial activity for use in agricultural productions. This study evaluated the inhibitory effect of X. nematophila TB culture on plant pathogens Botrytis cinerea and Phytophthora capsici. The cell-free filtrate of TB culture showed strong inhibitory effects (>90%) on mycelial growth of both pathogens. The methanol-extracted bioactive compounds (methanol extract) of TB culture also had strong inhibitory effects on mycelial growth and spore germinations of both pathogens. The methanol extract (1000 μg/mL) and cell-free filtrate both showed strong therapeutic and protective effects (>70%) on grey mold both in detached tomato fruits and plants, and leaf scorch in pepper plants. This study demonstrates X. nematophila TB produces antimicrobial metabolites of strong activity on plant pathogens, with great potential for controlling tomato grey mold and pepper leaf scorch and being used in integrated disease control to reduce chemical application.

Highlights

Inhibitory effect of Xenorhabdus nematophila TB on plant pathogens Phytophthora capsici and Botrytis cinerea in vitro and in planta
Previous studies have reported the variation in antimicrobial activities of different Xenorhabdus spp. strains to fungal pathogens . 9,18,24,27,35–39 B. cinerea and P. capsici are the frequently reported pathogens associated with tomato grey mold and pepper leaf scorch, respectively, which result in marked agricultural economic losses annually in China[40,41]
This study found that the cell-free filtrate of X. nematophila TB culture showed strong inhibitory effect on the growth of B. cinerea and P. capsici

Summary

Introduction

Inhibitory effect of Xenorhabdus nematophila TB on plant pathogens Phytophthora capsici and Botrytis cinerea in vitro and in planta. This study demonstrates X. nematophila TB produces antimicrobial metabolites of strong activity on plant pathogens, with great potential for controlling tomato grey mold and pepper leaf scorch and being used in integrated disease control to reduce chemical application. The most common fungal and oomycete pathogens belong to the genera Alternaria, Botrytis, Cochliobolus, Fusarium, Geotrichum, Penicillium, Sclerotina and Phytophthora, of which Botrytis cinerea and Phytophthora capsici are two of the most economically important pathogens on vegetables responsible for serious economic losses[1,2,3]. These pathogens are mainly controlled by chemical fungicides that most are highly toxic and non-biodegradable. Fourteen gene clusters involved in the biosynthesis of xenocoumacin have been identified by molecular genetic analysis[23]

Methods

Results

Conclusion