| 【Objective】The study was conducted to explore the changes of enzyme activity in rice resistant and susceptible near-isogenic lines infected with Xanthomonas oryzae pv.oryzicola（Xooc）, which provided a theoretical basis for studying the resistance mechanism of rice bacterial leaf streak（BLS）.【Method】With the rice BLS resistant near-isogenic line LR19 and susceptible near-isogenic line LS19 as materials, the treatment group was inoculated with pathogenic bacteria of Xooc by needling method, while the control group was inoculated with sterile water. The leaves at tillering stage of rice were taken as samples at 0, 24, 48 and 96 h after inoculation, and the changes of enzyme activities of
malondialdehyde（MDA）, catalase（CAT）, phenylalanine ammonia-lyase（PAL）, and peroxide enzyme（POD）, polyphenol oxidase（PPO）and superoxide dismutase（SOD）were analyzed.【Result】After inoculation, the average activities of CAT, PAL, POD, PPO and SOD in the LR19 treatment group were 269.36, 39.61, 31 677.75, 106.4 and 2 035.44 U/g, respectively, and those in the control group were 195.16, 33.23, 21 449.75, 85.67 and 1 139.38 U/g.The average activities of CAT, PAL, POD, PPO and SOD in the LS19 treatment group were 149.13, 34.3, 26 635.25, 87.6 and 1 354.82 U/g, respectively, and those in the control group were 73.95, 30.45, 10 506.43, 62.3 and 779.5 U/g, respectively. After being infected with Xooc, the activities of CAT, PAL, POD, PPO and SOD in both near-isogenic lines increased, and the activities of these five enzymes in LR19 were higher than those in LS19. However, the infection of Xooc reduced the MDA content in LR19 and LS19, and the MDA content of LR19 was generally lower than that of LS19.【Conclusion】The enhanced activity of CAT, PAL, POD, PPO and SOD is conducive to improving the resistance to BLS, while the accumulation of MDA content is negatively correlated to the BLS resistance.The activities of these enzymes can be used as supplementary evaluation indexes for identification of resistance to rice BLS. |
