The inhibitory effects of metabolites from Bacillus pumilus on potato virus Y and the induction of early response genes in Nicotiana tabacum

To develop a new antiviral preparation from a microbial source, the halophilic bacterium Bacillus pumilus E303035 was isolated from a soil sample collected at Qarhan Salt Lake in Qinghai, China. The inhibitory activity of an ethyl acetate extract of its fermentation broth was higher than that of an n-butanol extract. After isolation and purification, 9 compounds were obtained: cyclo(L-Leu-L-Pro) ( 1 ), cyclo(L-Pro-L-Tyr) ( 2 ), Brevianamide F ( 3 ), 2-(3-Indolyl) ethanol ( 4 ), N-[2-(1H-indol-3-yl) ethyl] acetamide ( 5 ), 3, 3-di(1H-indol-3-yl)propane-1,2-diol ( 6 ), Lincomycin B ( 7 ), dibutylphthalate ( 8 ), and p-hydroxyphenethyl alcohol ( 9 ). Compounds 1 , 5 , and 9 showed inhibitory activities against potato virus Y (PVY). Compounds 1 , 4 , and 9 had significant inhibitory activity against genes HC - pro , P3 , and Nib , compound 5 against gene P3 , and compounds 1 and 4 against NIa . Compounds 1 , 4 , 5 , and 9 had significant inhibitory activity against genes VPg and 6K1 . Active compounds 1 , 5 , and 9 had various effects on the expression of viral genes related to pathogenesis. Expression of genes cullin and XTH was up-regulated and CP was down-regulated, compared to the positive control. In conclusion, compounds 1 , 5 , and 9 might be considered as potential antiviral agents for future development.