MAPK基因MaHog1影响绿僵菌的逆境敏感性和毒力

Fungal biocontrol agents have great potential in integrated pest management. However, the poor efficacy and secnsitiveness to various adversities have hampered their wide application. In eukaryotic cells, Hog1 kinase play a critical role in stress responses. In this study, MaHog1 (GenBank accession number EFY85878) encodeing a member of the Hog1/Sty1/p38 MAPK family was identified from M. acridum. Targeted gene disruption was adopted to analyze the role of MaHog1 in virulence and tolerance to adverse factors. Mutant depleted for MaHog1 showed increased sensitivity to high osmotic stress, high temperature and oxidative stress and exhibited remarkable resistance to the cell wall disturbing agents. These results suggested that Hog1 kinase has conserved function in regulating multistress responses among fungi, and that MaHog1 might influence the cell wall biogenesis in M. acridum. Bioassays conducted with topical inoculation and intrahaemocoel injection revealed that MaHog1 is required for both the penetration and the postpenetration development of M. acridum. Disruption of MaHog1 resulted in a signi?cant reduction in virulence, likely due to the combination of a decrease in conidial germination, a reduction in appressorium formation, and a decline in growth rate in insect haemolymph, which might be caused by impairing the fungal tolerance to various stresses during infection.