Kumar Ashok, Sunish Kumar R, Sakthivel N
Department of Biotechnology, Pondicherry University, Kalapet, Pondicherry 605014, India.
Curr Microbiol. 2003 Apr;46(4):251-5. doi: 10.1007/s00284-002-3870-y.
Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, is known to produce phytotoxic polysaccharides. The extracellular polysaccharide (EPS) was isolated from virulent (BXO1) and virulence-deficient gum G mutant (BXO1002) strains of X. oryzae pv. oryzae and characterized using fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR). Data from the FT-IR suggested that the aldehyde (R-CHO) group and C=O of acid anhydride are present in BXO1 but absent in BXO1002. The (1)H-NMR spectra showed the presence of an acetyl amine of hexose or pentose, free amines of glucose, an beta-anomeric carbon of hexose and pentose, hydrogen next to hydroxyl group, an acetyl amine of hexose and pentose in the polysaccharides of both BXO1 and BXO1002, and the absence of alpha-anomeric carbon of hexose or pentose and the glucuronic acid in the polysaccharides produced by BXO1002. The test for glucuronic acid also confirmed the absence of glucuronic acid in the polysaccharides of BXO1002 and the presence glucuronic acid (32 microg/mg) in the polysaccharides produced by BXO1.
水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae）是水稻白叶枯病的病原菌，已知其能产生具有植物毒性的多糖。从水稻白叶枯病菌的强毒株（BXO1）和毒力缺陷型胶G突变株（BXO1002）中分离出细胞外多糖（EPS），并使用傅里叶变换红外光谱（FT-IR）和核磁共振（NMR）对其进行表征。FT-IR数据表明，BXO1中存在醛基（R-CHO）和酸酐的C=O，而BXO1002中不存在。（1）H-NMR光谱显示，BXO1和BXO1002的多糖中均存在己糖或戊糖的乙酰胺、葡萄糖的游离胺、己糖和戊糖的β-异头碳、羟基旁边的氢、己糖和戊糖的乙酰胺，且BXO1002产生的多糖中不存在己糖或戊糖的α-异头碳和葡萄糖醛酸。葡萄糖醛酸检测也证实了BXO1002的多糖中不存在葡萄糖醛酸，而BXO1产生的多糖中存在葡萄糖醛酸（32微克/毫克）。
