Phytochromes Regulate SA and JA Signaling Pathways in Rice and Are Required for Developmentally Controlled Resistance to Magnaporthe grisea  

作　　者：Xian-Zhi Xie Yan-Jiu Xue Jin-Jun Zhou Bin Zhang Hong Chang Makoto Takano 

机构地区：[1]High-Tech Research Center, Shandong Academy of Agricultural Sciences, Jinan 250100, PR China [2]Laboratory of Crop Genetic Improvement and Biotechnology, Huanghuaihai, Ministry of Agriculture, Jinan 250100, PR China [3]College of Life Science, Shanxi Agricultural University, Taigu,Shanxi 030801, PR China [4]National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan

出　　处：《Molecular Plant》2011年第4期688-696,共9页分子植物（英文版）

摘　　要：Old leaves of wild-type rice plants （Oryza sativa L. cv. Nipponbare） are more resistant to blast fungus （Magnaporthe grisea） than new leaves. In contrast, both old and new leaves of the rice phytochrome triple mutant （phyAphyBphyC） are susceptible to blast fungus. We demonstrate that pathogenesis-related class 1 （PR1） proteins are rapidly and strongly induced during M. grisea infection and following exogenous jasmonate （JA） or salicylic acid （SA） exposure in the old leaves, but not in the new leaves of the wild-type. In contrast, the accumulation of PR1 proteins was significantly attenuated in old and new leaves of the phyAphyBphyC mutant. These results suggest that phytochromes are required for the induction of PR1 proteins in rice. Basal transcription levels of PRla and PRlb were substantially higher in the wildtype as compared to the phyAphyBphyC mutant, suggesting that phytochromes also are required for basal expression of PR1 genes. Moreover, the transcript levels of genes known to function in SA- or JA-dependent defense pathways were regulated by leaf age and functional phytochromes. Taken together, our findings demonstrate that phytochromes are required in rice for age-related resistance to M. grisea and may indirectly increase PR1 gene expression by regulating SA- and JA-dependent defense pathways.Old leaves of wild-type rice plants （Oryza sativa L. cv. Nipponbare） are more resistant to blast fungus （Magnaporthe grisea） than new leaves. In contrast, both old and new leaves of the rice phytochrome triple mutant （phyAphyBphyC） are susceptible to blast fungus. We demonstrate that pathogenesis-related class 1 （PR1） proteins are rapidly and strongly induced during M. grisea infection and following exogenous jasmonate （JA） or salicylic acid （SA） exposure in the old leaves, but not in the new leaves of the wild-type. In contrast, the accumulation of PR1 proteins was significantly attenuated in old and new leaves of the phyAphyBphyC mutant. These results suggest that phytochromes are required for the induction of PR1 proteins in rice. Basal transcription levels of PRla and PRlb were substantially higher in the wildtype as compared to the phyAphyBphyC mutant, suggesting that phytochromes also are required for basal expression of PR1 genes. Moreover, the transcript levels of genes known to function in SA- or JA-dependent defense pathways were regulated by leaf age and functional phytochromes. Taken together, our findings demonstrate that phytochromes are required in rice for age-related resistance to M. grisea and may indirectly increase PR1 gene expression by regulating SA- and JA-dependent defense pathways.

关 键 词：RICE PHYTOCHROME JASMONATE salicylic acid defense. 

分 类 号：S511[农业科学—作物学] Q945.11[生物学—植物学]