A plant biostimulant made from the marine brown algae Ascophyllum nodosum and chitosan reduce Fusarium head blight and mycotoxin contamination in wheat.

L R Gunupuru,J B Renaud,J S Patel,M W Sumarah,E G Mantin,B Prithiviraj,Aimin Zhang

doi:10.1371/journal.pone.0220562

Abstract

Fusarium head blight (FHB) caused by Fusarium graminearum is a disease that results in yield loss and mycotoxin contamination in wheat globally. This study assessed the effect of a plant biostimulant prepared from a brown macroalga Ascophyllum nodosum (Liquid Seaweed Extract; LSE) alone and in combination with chitosan in controlling Fusarium. Wheat seedlings drenched with LSE and chitosan in combination showed reduced severity of F. graminearum infection on leaves as evidenced by a significant reduction in necrotic area and fewer number of conidia produced in the necrotic area. Gene expression studies showed that the combination of LSE and chitosan amplified the response of pathogenesis-related genes (TaPR1.1, TaPR2, TaPR3, TaGlu2) in wheat seedlings infected with Fusarium spores above that observed for the individual treatments. The combination treatments were more effective in enhancing the activity of various defense related enzymes such as peroxidase and polyphenol oxidase. FHB studies on adult plants showed a reduction of bleached spikes in wheat heads treated with the combination of LSE and chitosan. Mycotoxin content appeared to be correlated with FHB severity. Combination treatments of LSE and chitosan reduced the levels of mycotoxins deoxynivalenol and sambucinol in wheat grains. Systemic disease resistance appears to be induced by LSE and chitosan in response to F. graminearum in wheat by inducing defense genes and enzymes.

Highlights

Plants possess inducible defense mechanisms, utilizing effector molecules to defend against pathogens [1]
There was a significant reduction in the number of conidia produced per leaf in all treatments compared to the control, except T3 (Fig 1C)
The strongest effect was observed in the combination treatment containing LSE (15 mL L-1) and chitosan (T6), exhibiting a reduction of 84% in the number of conidia produced when compared to the control treatment

Summary

Introduction

Plants possess inducible defense mechanisms, utilizing effector molecules to defend against pathogens [1]. Plant defense responses are induced by the application of elicitor molecules in two ways: locally or systemically. These elicitor molecules are isolated from a number of sources including plants, animals, cell wall components of microbes and cellular components of avirulent pathogens [2,3]. Seaweeds are a rich source of bioactive compounds that reportedly enhance plant productivity and improve overall plant health.

Methods

Results

Conclusion