Subramoni Sujatha, Sonti Ramesh V
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500 007, India.
Mol Plant Microbe Interact. 2005 Jul;18(7):644-51. doi: 10.1094/MPMI-18-0644.
Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. A mutation was isolated in the ferric uptake regulator (fur) gene of X. oryzae pv. oryzae and it was shown to result in the production of siderophores in a constitutive manner. The fur mutant is hypersensitive to the metallo-antibiotic streptonigrin, a phenotype that is indicative of intracellular free-iron overload, and also exhibits a slow growth phenotype on rich medium. The fur mutant is virulence deficient, hypersensitive to hydrogen peroxide, and exhibits reduced catalase activity. Exogenous supplementation with ascorbic acid (an antioxidant) rescues the growth deficiency of the fur mutant in rice leaves. The virulence deficiency of the X. oryzae pv. oryzae fur mutant is proposed to be due, at least in part, to an impaired ability to cope with the oxidative stress conditions that are encountered during infection.
水稻白叶枯病菌引起水稻细菌性条斑病，这是一种严重的水稻病害。在水稻白叶枯病菌的铁摄取调节蛋白（fur）基因中分离到一个突变体，该突变体被证明能组成型地产生铁载体。fur突变体对金属抗生素链黑菌素高度敏感，这种表型表明细胞内游离铁过载，并且在丰富培养基上也表现出生长缓慢的表型。fur突变体的毒力缺陷，对过氧化氢高度敏感，并且过氧化氢酶活性降低。用抗坏血酸（一种抗氧化剂）进行外源补充可挽救fur突变体在水稻叶片中的生长缺陷。水稻白叶枯病菌fur突变体的毒力缺陷至少部分是由于其应对感染过程中遇到的氧化应激条件的能力受损所致。
