A. Germination rate were tested after wet-heat exposure to temperature of 45°C for 0, 1.0, 1.5 2.0, 2.5 and 3.0 h. B. Germination rate after UV-radiation exposure for

0, 1, 2, 3 and 4 h. Standard deviation bars denote standard deviations for three independent experiments. *: significant difference, p <0.05; **: significant difference, p <0.01. Discussion Adenylate cyclase regulates LBH589 mw a variety of physiological processes in phytopathogenic fungi, including conidiation, conidial germination, vegetative growth, appressoria formation and virulence. In this study, an adenylate cyclase gene, MaAC, was identified in a locust-specific entomopathogenic fungus, M. acridum. Bioinformatic analysis showed that the cloned MaAC had significant similarity to its homolog from M. oryzae and to many other fungal adenylate cyclase genes; the highest degree of similarity Seliciclib mouse was found with the adenylate cyclase of M. anisopliae (98% identity). The cAMP level of the MaAC RNAi mutant was significantly reduced, and the exogenous addition of cAMP could restore the growth of the RNAi mutant, thus confirming that the MaAC gene encodes adenylate cyclase in M. acridum. These results were similar to previous studies on other fungi [10, 12,

14]. Following the deletion of the entire SAC1 coding sequence of S. sclerotiorum[10], cAMP underwent a four-fold reduction in the SAC1 deletion strain compared to the wild type. In BAC1- and UAC1-defective

mutants, intracellular cAMP was detected, which contrasted with the wild type [13, 15]. In this report, the downregulation of MaAC led to inhibited growth on in vitro media, including PDA and Czapek-dox medium. In PD liquid culture, it caused similar effects to previously described adenylate cyclase mutants, such as the SAC1 mutant in S. sclerotiorum[10] and the BAC1 mutant in B. cinerea[12]. Furthermore, MaAC is also involved in the growth of M. acridum inside locusts. The virulence of the MaAC mutant was also significantly reduced, thus indicating that MaAC is required for M. acridum virulence. This finding is consistent with the role of adenylate cyclase in the virulence of Cyclin-dependent kinase 3 other fungi, including M. oryzae[11], B. cinerea[12] and U. maydis[15]. Previous research has demonstrated that the tolerance of fungi to stresses such as high temperature [13], UV-B radiation [8, 16], oxidative [13] and osmotic stress [4, 5, 17] is a factor that limits their widespread use. The elevated thermo- and H2O2-tolerance of the ΔFpacy1 mutants indicated that the adenylate cyclase may have negative regulatory roles on the stress response mechanisms of fungal cells [13]. However, the tolerance of the RNAi mutant to the osmotic-, H2O2-, UV-B and thermal stress was reduced in this study, thus indicating that MaAC may affect the tolerance to multiple stresses through similar regulatory mechanisms in fungal cells.