Sawada Kazutoshi, Hasegawa Morifumi, Tokuda Lena, Kameyama Junko, Kodama Osamu, Kohchi Takayuki, Yoshida Kazuya, Shinmyo Atsuhiko
Research Association for Biotechnology, Ikoma, Nara, Japan.
Biosci Biotechnol Biochem. 2004 Apr;68(4):873-80. doi: 10.1271/bbb.68.873.
The rice Oryza sativa selenium-binding protein homologue (OsSBP) gene encodes a homologue of mammalian selenium-binding proteins, and it has been isolated as one of the genes induced by treating a plant with a cerebroside elicitor from rice blast fungus. The possible role of OsSBP in plant defense was evaluated by using a transgenic approach. Plants overexpressing OsSBP showed enhanced resistance to a virulent strain of rice blast fungus as well as to rice bacterial blight. The expression of defense-related genes and the accumulation of phytoalexin after infection by rice blast fungus were accelerated in the OsSBP overexpressors. A higher level of H(2)O(2) accumulation and reduced activity of such scavenging enzymes as ascorbate peroxidase and catalase were seen when the OsSBP-overexpressing plants were treated with the protein phosphatase 1 inhibitor, calyculin A. These results suggest that the upregulation of OsSBP expression conferred enhanced tolerance to different pathogens, possibly by increasing plant sensitivity to endogenous defense responses. Additionally, the OsSBP protein might have a role in modulating the defense mechanism to biotic stress in rice.
水稻（Oryza sativa）硒结合蛋白同源物（OsSBP）基因编码一种哺乳动物硒结合蛋白的同源物，它是作为用稻瘟病菌的脑苷脂激发子处理植物后诱导产生的基因之一被分离出来的。通过转基因方法评估了OsSBP在植物防御中的可能作用。过表达OsSBP的植物对稻瘟病菌的强毒株以及水稻白叶枯病表现出增强的抗性。在OsSBP过表达植株中，稻瘟病菌感染后防御相关基因的表达和植保素的积累加快。当用蛋白磷酸酶1抑制剂花萼海绵诱癌素A处理过表达OsSBP的植物时，会观察到更高水平的H₂O₂积累以及抗坏血酸过氧化物酶和过氧化氢酶等清除酶的活性降低。这些结果表明，OsSBP表达的上调可能通过增加植物对内源防御反应的敏感性赋予了对不同病原体更强的耐受性。此外，OsSBP蛋白可能在调节水稻对生物胁迫的防御机制中发挥作用。
