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Overexpression of Rice (Oryza sativa L.) OsCDR1 Leads to Constitutive Activation of Defense Responses in Rice and Arabidopsis

December 2009 , Volume 22 , Number  12
Pages  1,635 - 1,644

Bishun Deo Prasad,1 Gary Creissen,2 Chris Lamb,2 and Bharat B. Chattoo1

1Genome Research Centre, Department of Microbiology and Biotechnology Centre, Faculty of Science, The M. S. University of Baroda, Vadodara, Gujarat-390002, India; 2John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, U.K.

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Accepted 28 July 2009.

Plant aspartic proteases (AP) play key roles in the regulation of biological processes, such as the recognition of pathogens and pests and the induction of effective defense responses. A large number of AP (>400) have been identified in silico in the rice genome. None have previously been isolated and functionally characterized for their involvement in disease resistance. We describe here the isolation and characterization of a gene (OsCDR1) from rice which encodes a predicted aspartate protease. Expression of OsCDR1 was activated upon treatments with benzothiadiazole and salicylic acid, which are signal molecules in plant disease resistance responses. Ectopic expression of OsCDR1 in Arabidopsis and rice conferred enhanced resistance against bacterial and fungal pathogens. The enhanced disease resistance observed in transgenic plants was correlated with induction of pathogenesis-related gene expression and was shown by mutational analysis to be dependent on AP activity of the transgene-encoded product. OsCDR1 accumulates in intercellular fluids (IF) in transgenic plants. Infiltration of IF from transgenic Arabidopsis plants into leaves of wild-type (WT) Arabidopsis induced the systemic defense response. These results demonstrate the conservation of CDR1 function between rice and Arabidopsis during the disease resistance response.

© 2009 The American Phytopathological Society