Characteristic Expression Of Pathogenesis-related Proteins In Rice Development And Interaction With Xanthomonas Oryzae Pv.oryzae

Background: Rice(Oryza sativa)is a very important crop, rice disease can reduce the yield of rice, it can even result in the lost of harvest. With the completion of the Rice Genome Project, the next step forward is to define the biological function of target proteins. Rice bacterial blight is one of the most important rice diseases.The study to the mechanism of rice disease resistance gene has great significances.Aim: Ten antibodies which are PR proteins-specific were prepared in our endeavour to understand the expression of PR proteins in rice. Then we screened PR protein which associated with the Xa21-mediated resistance against bacterial leaf blight. And we provided experimental evidence for classification of recently found PR protein in rice.Material and method: we prepared 10 antibodies of PR protein-specific that used fusion protein expression or polypeptide synthesis. We monitored the developmental expression profiles of the corresponding proteins in rice leaves, further we examined their expression at different time points in the Xa21-mediated resistance against bacterial leaf blight.Results: We found that most of them expressed at different developmental stages of the leaves. Moreover the expression of PR1,PR2,PR3,PR4b,PR8 and PR-pha or their modified bands were up-regulated in the later period of the resistance reaction. Comparing their expression in the resistance, susceptible and Mock responses, we found that changes in resistance and susceptible responses were more obvious than those in Mock response. Furthermore, most of the changes in the susceptible response were more obvious than those in the disease resistance response. Changes of expression in resistance response were not detected in PR5,PR6,PR15 and PR16, during the susceptible response, expression of PR5 and PR16 was different from that of disease resistance and Mock. We didn't detect the expression changes of PR6 and PR16 proteins in the resistance, susceptible and Mock responses.Conclusion: Pathogenesis-related proteins (PR_s) are often induced when plants are subjected to pathogen infection. PR1, PR2, PR3, R4b, PR8 and PR-pha proteins played a role in both of the resistance and susceptible responses, which are related with the degrees of their expression. During the susceptible response, expression of PR5 and PR16 was different from that of disease resistance and Mock. So we inferred that both of them played a role in the susceptible response; we didn't detect the expression changes of PR6 and PR16 proteins in the resistance, susceptible and Mock responses. Our study revealed that the expression of PR proteins is relevant to the resistance and susceptible responses in the interaction between rice and Xanthomonas oryzae pv. Oryzae (Xoo).