青枯菌侵染不同抗病烟草品种的防御性酶活性及代谢组分差异分析

【目的】为烟草抗病育种和抗性鉴定提供生化代谢指标。【方法】采用茎部注射法对抗病品种粤烟97和感病品种长脖黄接种青枯雷尔菌Ralstonia solanacearum,并采用比色法和GC-MS法分别进行相关防御性酶活性及代谢物质的测定。【结果】抗病品种粤烟97的PAL、SOD、POD、PPO活性,接菌组与对照组均分别高于感病品种长脖黄的接菌组与对照组;抗病品种粤烟97和感病品种长脖黄分别在接菌后第7天和第5天,PAL活性高于对照组,其余时间酶活性接菌组均低于对照组;抗病品种粤烟97和感病品种长脖黄在受青枯雷尔菌侵染前期,SOD、POD、PPO酶活性均提高,随着时间延长酶活性均低于对照组。POD和PPO同工酶凝胶电泳表明:抗病品种粤烟97同工酶类型多于感病品种长脖黄;接菌后第3天,粤烟97的同工酶谱带宽度与色度增强,而长脖黄无增强现象。说明抗病品种能快速应对外界刺激,加速相关抗病物质的形成。代谢物检测表明:抗病品种粤烟97接菌组中肌肉肌醇、烟碱、苹果酸、L-苏氨酸等物质的相对质量分数高于对照组,而感病品种长脖黄接菌组中这些物质均低于对照组,反映品种间抗青枯病能力的强弱可能与上述物质有关。【结论】烟草不同抗病品种叶片中PAL、SOD、POD、PPO酶活性的高低,以及上述代谢物质含量的变化,可作为反映烟草抗青枯病的生化指标。

Differences of defensive enzyme activities and metabolites between resistant and susceptible tobacco cultivars infected by Ralstonia solanacearum

Objective] In order to provide the biochemical and metabolic basis of tobacco breeding for disease resistance and resistance identification .Method]Resistant ( Yueyan 97 ) and susceptible ( Changbohuang ) tobacco cultivars were inoculated with Ralstonia solanacearum by trunk injection . Defensive enzyme activities and metabolites were measured by using colorimetric method and GC-MS.Result]The activities of phenylanine ammonia lyase ( PAL) , superoxide dismutase ( SOD) , peroxidase (POD) and polyphenol oxidase (PPO) in the resistant cultivar ‘Yueyan 97’ were higher than those in the susceptible cultivar ‘Changbohuang ’ with the same inoculation treatment .The PAL activities of Yueyan 97 and Changbohuang were higher than that in control on the seventh and fifth days after inocula -tion, respectively .The PAL activities of both cultivars were lower compared to control at any other time . For both cultivars, SOD, POD and PPO activities increased compared to control in the earlier days , but were lower compared to control during the later time period .The types of POD and PPO isozymes in the resistant cultivar ‘Yueyan 97 ’ were higher than those in the susceptible cultivar ‘Changbohuang ’ .The width and color of isozyme bands of Yueyan 97 were enhanced at 3 d after inoculation , while those of Changbohuang were not enhanced .It suggested that the resistant cultivar could quickly respond to exter-nal stimuli and accelerate the formation of defense-related substances .Detection of metabolites showed that the relative contents of some substances in Yueyan 97 such as myo-inositol , nicotine , malic acid , and L-threonine were higher compared to control , but in Changbohuang were lower compared to control , suggesting that cultivar differences in resistance against R.solanacearum might be related to these sub-stances .Conclusion] These four defensive enzyme activities and the contents of the above metabolites could be used as biochemical indexes for evaluating tobacco resistance against R.solanacearum.