Mechanism of HOG-MAPK pathway in regulating mycotoxins formation under environmental stresses

Abstract

In order to adapt to different environmental stresses including heat stress, oxidative stress, osmotic pressure stress and ultraviolet stress in the process of growing and infecting agricultural products, fungi have developed a set of high osmolarity glycerol mitogen-activated protein kinase (HOG-MAPK) pathway to alleviate the environmental stresses. This pathway plays an important role in the growth, development, mycotoxin production and pathogenicity of fungi. There are two branches in the HOG-MAPK pathway, among which the SLN1 branch is more sensitive to osmotic stress than another branch (SHO1 branch), and is able to respond to high osmotic pressure and high salt concentration. The SHO1 branch is involved in a variety of signal transduction in response to oxidative stress and thermal stress. This paper reviews the functions of key genes sln1, sho1, ste11, ssk2, pbs2 and hog1 in the HOG-MAPK pathway of phytopathogenic fungi in responses to different environmental stresses such as osmotic stress and oxidative stress. We show that the HOG-MAPK pathway can respond to a variety of environmental signals and is involved in regulating the growth of phytopathogenic fungi such as Aspergillus flavus and Aspergillus ochraceus, and the production of mycotoxins such as aflatoxins and ochratoxins. Understanding the mechanism of how HOG-MAPK pathway regulates mycotoxins' formation under different environmental stresses that provides a theoretical basis and guidance for the prevention and control of mycotoxins in agricultural products such as food and feed.