LAUSR

Microorganism isolates (n = 49) were obtained from the soil samples collected from field in Gotsu city (Kawahira), Shimane. Isolate GT2-E culture inhibited the growth of Xanthomonas oryzae pv. oryzae in disk diffusion method. Rice bacterial leaf blight was suppressed by GT2-E culture in the pre- and post-treated rice leaves. Sequence analysis of 16S rDNA region of the GT2-E isolate indicated that it shared 99% similarity with Paenibacillus polymyxa. The growth of GT2-E on LB medium was observed at 15°C, 28°C, 37°C, and 45°C, but not at 4°C. GT2-E isolate could be grown even in the presence of agrochemicals (Amister, Blasin and Kasumin). Furthermore, the growth of X. oryzae pv. oryzae was inhibited by the culture filtrate of GT2-E isolate in disk diffusion method. However, the inhibitory activity of the culture filtrate was heat-unstable. This result suggested that GT2-E isolate can produce heat-unstable inhibitory compound(s). In conclusion, GT2-E isolate might contribute to the development of a new bactericide and biological agent against rice bacterial leaf blight.