Bacteria Causing Grain Rot of Rice

Abstract

Eighty-three pathogenic bacteria were obtained from diseased grains of rice plants which were collected from various localities in Japan during the period from 1973 to 1980. These bacterial isolates were divided into 4 groups according to their bacteriological characteristics and pathogenics traits, and identified as follows: the 1st group of 14 isolates was Pseudomonas glumae; the 2nd group of 16 isolates was P. syringae pv. aptata; and the 3rd group of 26 isolates was a species related to P. fluorescens. The 4th group of 27 isolates belongs to a genus other than Pseudomonas and was not identified. These four groups were easily distinguished by the following characteristics: relation to free oxygen; requirement of growth facters; ability to grow under 40C; production of green fluorescent pigment; activity of oxidase and arginine dihydrolase and nitrate reductase. Antiserum to the isolate NIAES 1169 of P. glumae reacted with the isolates of P. glumae but did not react with the isolates belonging to the other 3 groups of bacteria. All the isolates of 4 groups attacked grains of rice plants and produced similar early symptoms to each other, but the only isolate of P. glumae attacked rice seedlings.