Ono E, Wong H L, Kawasaki T, Hasegawa M, Kodama O, Shimamoto K
Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan.
Proc Natl Acad Sci U S A. 2001 Jan 16;98(2):759-64. doi: 10.1073/pnas.98.2.759. Epub 2001 Jan 9.
Production of reactive oxygen intermediates (ROI) and a form of programmed cell death called hypersensitive response (HR) are often associated with disease resistance of plants. We have previously shown that the Rac homolog of rice, OsRac1, is a regulator of ROI production and cell death in rice. Here we show that the constitutively active OsRac1 (i) causes HR-like responses and greatly reduces disease lesions against a virulent race of the rice blast fungus; (ii) causes resistance against a virulent race of bacterial blight; and (iii) causes enhanced production of a phytoalexin and alters expression of defense-related genes. The dominant-negative OsRac1 suppresses elicitor-induced ROI production in transgenic cell cultures, and in plants suppresses the HR induced by the avirulent race of the fungus. Taken together, our findings strongly suggest that OsRac1 has a general role in disease resistance of rice.
活性氧中间体（ROI）的产生以及一种被称为过敏反应（HR）的程序性细胞死亡形式通常与植物的抗病性相关。我们之前已经表明，水稻的Rac同源物OsRac1是水稻中ROI产生和细胞死亡的调节因子。在此我们表明，组成型激活的OsRac1（i）引发类过敏反应，并极大地减少针对稻瘟病菌强毒株的病害病斑；（ii）对细菌性条斑病的强毒株产生抗性；以及（iii）导致植保素的产生增加并改变防御相关基因的表达。显性负性OsRac1在转基因细胞培养物中抑制激发子诱导的ROI产生，在植物中抑制由无毒真菌菌株诱导的过敏反应。综上所述，我们的研究结果强烈表明OsRac1在水稻抗病性中具有普遍作用。
