Expression of Hog1 Gene in Metarhizium Strain MAX-2 in Response to Adversity Stresses

Purpose Transcriptional expression of Hog1 gene in Metarhizium strain MAX-2 was analyzed under adversity stresses to reveal the molecular mechanism of its adverse tolerance.

Method The conidia of 3 Metarhizium strains (MAX-2, BUM2495 and BUM723) with different adverse tolerance abilities were treated with salt (0.4 mol/L and 0.8 mol/L NaCl) and ultraviolet radiation (5 min and 15 min). Their conidial germination rates were tested. Their RNA were extracted and the expression differences of Hog1 were analyzed by the method of semi-quantitative RT-PCR.

Result From the conidial germination of strains under salt and ultraviolet stresses, the adverse tolerant abilities of the three Metarhizium strains were MAX-2>BUM2495>BUM723 and the differences between strains were extremely significant (P<0.01). The salt treatment and ultraviolet radiation could induce the upregulation of the expression forMetarhizium Hog1, while the expression difference of different strains was significant. The expression level of MAX-2 was the highest and that of BUM723 was the lowest. The expression level of MAX-2 was a little higher than BUM2495 under a lower level of stress conditions (0.4 mol/L NaCl and 5 min of ultraviolet radiation) and significantly higher than BUM2495 under a higher level of stress conditions (0.8 mol/L NaCl and 15 min of ultraviolet radiation), suggesting that the higher expression of Hog1 under the higher level of stress condition was closely related to the adverse tolerance of MAX-2.

Conclusion The higher adverse tolerance of Metarhizium strain MAX-2 was related to its higher level of transcriptional expression.