Phytotoxic Metabolites Produce by Fusarium oxysporum f. sp. cubense Race 2.

N Portal González,L Herrera Isla,A Soler,J Solano,B Companioni,C Ribadeneira,Roxana Portieles,Ramon Santos Bermudez,Orlando Borras-Hidalgo

doi:10.3389/fmicb.2021.629395

Abstract

Banana is a major tropical fruit crop but banana production worldwide is seriously threatened due to Fusarium wilt. Fusarium oxysporum f. sp. cubense (Foc), the causal agent of Fusarium wilt of banana (also referred as Panama disease) is an asexual, soil inhabiting facultative parasite. Foc isolates can be classified into three races that are not defined genetically, but for their pathogenicity to different banana cultivars. Despite mycotoxins being some of the best studied virulence factors of phytopathogenic fungi and these have been useful for the prediction of Foc virulence on banana plants, toxins produced by Foc race 2 strains have not been previously identified. The aim of this contribution was to identify the phytotoxic metabolites closely related to banana wilt caused by a Foc race 2 strain. We used an in vitro bioassay on detached banana leaves to evaluate the specificity of the microbial culture filtrates before a partial purification and further identification of Foc race 2 phytotoxins. A 29-day-old host-specific culture filtrate was obtained but specificity of culture filtrate was unrecovered after partial purification. The non-specific phytotoxins were characterized as fusaric acid, beauvericin, and enniatin A. Whereas some, if not all, of these phytotoxins are important virulence factors, a proteinaceous fraction from the specific 29-day-old culture filtrate protected the leaves of the resistant banana cultivar from damage caused by such phytotoxic metabolites.

Highlights

Banana is a major tropical fruit crop and the staple food of millions of people around the world
The leaves used in the experiments were sampled from 8 to 9-month-old field-grown banana plants of cultivars “Bluggoe” (Musa affects the hybrid triploid cultivar “Bluggoe” (ABB)) and “Grande Naine” (Musa AAA), which have a field-behavior of susceptibility and resistance to Foc race 2, respectively
It has been widely accepted that mycotoxins were produced simultaneously with fungal growth, and the rate of production is proportional to its growth rate (Shao et al, 2020)

Summary

Introduction

Banana is a major tropical fruit crop and the staple food of millions of people around the world. Banana production worldwide is seriously threatened due to Fusarium wilt, previously referred as Panama disease, caused by Fusarium oxysporum f. Fusarium wilt of banana is a classical vascular wilt disease (Ploetz, 2019). The vascular wilt fungus Fusarium oxysporum is an asexual, soil inhabiting facultative parasite (Li et al, 2019)

Methods

Results

Conclusion