Differential Roles of Three α-Crystallin Domain-Containing sHsps of in Asexual Development, Multiple Stress Tolerance and Virulence.

Small heat shock proteins (sHsps) containing conserved α-crystallin domain play important roles in many cellular processes, but little is known about the functions of sHsps in filamentous entomopathogens. Here, three sHsps of Hsp20, Hsp30a, and Hsp30b were characterized in , a filamentous fungal insect pathogen that serves as the main source of wide-spectrum fungal insecticides. The results demonstrated that these three genes are interrelated at the transcriptional level under normal and heat-shocked conditions. Meanwhile, all the deletion mutants showed significant but differential changes in cell wall integrity, antioxidant activity, hyphal tolerance to carbendazim fungicide, conidial tolerance to 45 °C wet heat and virulence. However, only showed growth defects on rich and minimal media at 25 °C and displayed the reduction in conidiophores and conidia. Moreover, the single deletion of and caused the decreases in hyphal growth at 34 °C and conidial tolerance to UV-B irradiation. Our findings provide a global insight into vital roles of , , and in asexual development, environmental adaptation, and fungal virulence of .