Antifungal Activity of Quinofumelin against Fusarium graminearum and Its Inhibitory Effect on DON Biosynthesis.

Qian Xiu,Yabing Duan,Mingguo Zhou,Zehua Zhou,Haorong Xu,Tao Li,Zhongke Li,Lianyu Bi,Jianxin Wang

doi:10.3390/toxins13050348

Abstract

Fusarium graminearum, causal agent of Fusarium head blight (FHB), causes a huge economic loss. No information is available on the activity of quinofumelin, a novel quinoline fungicide, against F. graminearum or other phytopathogens. In this study, we used mycelial growth and spore germination inhibition methods to determine the inhibitory effect of quinofumelin against F. graminearum in vitro. The results indicated that quinofumelin excellently inhibited mycelial growth and spore germination of F. graminearum, with the average EC50 values of 0.019 ± 0.007 μg/mL and 0.087 ± 0.024 μg/mL, respectively. In addition, we found that quinofumelin could significantly decrease deoxynivalenol (DON) production and inhibit the expression of DON-related gene TRI5 in F. graminearum. Furthermore, we found that quinofumelin could disrupt the formation of Fusarium toxisome, a structure for producing DON. Western blot analysis demonstrated that the translation level of TRI1, a marker gene for Fusarium toxisome, was suppressed by quinofumelin. The protective and curative assays indicated that quinofumelin had an excellent control efficiency against F. graminearum on wheat coleoptiles. Taken together, quinofumelin exhibits not only an excellent antifungal activity on mycelial growth and spore germination, but also could inhibit DON biosynthesis in F. graminearum. The findings provide a novel candidate for controlling FHB caused by F. graminearum.

Highlights

Fusarium head blight (FHB), primarily caused by Fusarium graminearum species complex (FGSC), is one of the major diseases in wheat in the wheat growing regions of the world [1,2]
Applimycotoxins produced by F. graminearum, which is unsafe for human consumption, animal feed and malting produce and poses a serious threat to food safety [7]
As most wheat cultivars are susceptible to Fusarium species, the primary method to manage FHB is fungicide application

Summary

Introduction

Fusarium head blight (FHB), primarily caused by Fusarium graminearum species complex (FGSC), is one of the major diseases in wheat in the wheat growing regions of the world [1,2]. FHB pathogens can invade wheat at different stages of growth, causing seedling rot, stem rot or wheat ear rot. FHB pathogens mainly invade the panicle, causing rot of the spikelet or the whole wheatear, resulting in the shrinkage of kernels or head blight. More than 5.4 Mha, which accounts for about 23% of the total wheat production area of China, were affected by the disease each year between 2000 and 2018 [3]. In America, the wheat production caused by FHB was reduced up to 501 million bushels in the early

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Conclusion