Abstract
Pseudomonas glumae, the causal agent of the grain rot and seedling rot of rice, is known to show antibacterial activities against other plant pathogenic bacteria and caused rotting of potato tuber slices. In this study, 50 mutant strains were raised from a strain Kyu82-34-2, which produced water soluble, yellowish-green pigment on YPDA or in YPD medium, by NTG (N-methyl-N'-nitro-N-nitrosoguanidine)-treatment. The mutant strains were compared each other in pigment productivity, antibacterial activities to several plant pathogenic bacteria, potato rotting activity and virulence to rice seedlings. All of the 28 pigment productive strains were virulent to rice seedlings and potato tuber slices. Almost all of pigment non-productive strains were avirulent to rice seedlings with only exception of two strains, NT49 and NT106. Pigment productive strains showed wider antibacterial spectra with higher activities as compared to pigment non-productive strains. About a half of the mutant strains lost both pigment productivity and potato rotting activity.
