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松材线虫病已对中国森林资源以及生态环境造成严重破坏和威胁.近年信号分子H2O2在植物病害中的作用已成为研究热点,然而对松树-松材线虫互作中H2O2方面的功能研究不多见.本实验以三年生黑松(Pinus thunbergii)为材料,通过施用外源H2O2供给剂和抑制剂(AsA)探讨H2O2对松树-松材线虫互作体系中抗氧化保护酶、苯丙烷代谢途径的调控作用;同时对黑松感染松材线虫后体内H2O2产生的酶途径加以研究.结果表明,外源H2O2处理提前诱发了染虫黑松体内H2O2含量大幅度升高;AsA可在接种早期抑制染虫黑松体内H2O2含量,推迟了H2O2大量积累的发生.同步测定染虫黑松体内相关酶活性发现,外源H2O2处理后,染虫黑松体内APX和CAT活性下降幅度更大,MDA含量、PAL酶活性均提前积累;而外源AsA处理则推迟染虫黑松体内APX和CAT活性大幅下降的发生,延迟且削弱了MDA含量大量积累的发生和累积程度,PAL酶活性升高也滞后.同步观察黑松感病症状,发现H2O2处理组染虫黑松发病最快;仅接种松材线虫处理组次之;AsA处理组染虫黑松发病最慢.这表明,受松材线虫侵染后,黑松体内大量累积的信号分子H2O2可影响寄主体内抗氧化保护酶活性、苯丙烷代谢途径的表达,进一步影响了感病症状的表达.对黑松体内H2O2产生酶来源研究发现,黄嘌呤氧化酶(XO)抑制剂别嘌呤醇和NADPH氧化酶抑制剂二亚苯基碘(DPI)处理均能明显抑制黑松体内H2O2含量,说明XO和NADPH氧化酶均是黑松与松材线虫互作体系中内源H2O2合成的重要酶.
Pine wilt disease has caused serious damage and threat to forest resources and environment in China.In recent years, the role of signaling molecule H2O2 in plant diseases has become a research hotspot, but there is not much research on the function of H2O2 in pine-pine worm interaction In this experiment, Pinus thunbergii as the material, through the application of exogenous H2O2 supply and inhibitor (AsA) to explore the H2O2 on the pine-pine wood nematode interaction system antioxidant enzyme, phenylpropanoid metabolic pathway And the enzyme pathway of H2O2 production in the body of pine wood nematode infected with pine wood nematode was studied.The results showed that the content of H2O2 in the black pine body caused by exogenous H2O2 pretreatment significantly increased and AsA could be inhibited in the early stage of inoculation The content of H2O2 in the infected black pine was delayed, and the accumulation of H2O2 was postponed. Simultaneous determination of the related enzyme activities in the infected black pine showed that the activities of APX and CAT decreased more significantly after exposure to H2O2, , And PAL activity accumulated earlier. Exogenous AsA delayed the sharp decline of APX and CAT activity in the infected black pine, delayed and weakened the occurrence and accumulation of large amount of MDA , And the PAL activity increased and lagged.While observing the symptom of black pine simultaneously, it was found that the incidence of black pine was the fastest in H2O2-treated group, followed by that of pine wood nematode inoculation alone, and that of AsA-treated group was the slowest. This indicates that after being infected by pine wood nematode, a large number of H2O2 signal molecules accumulated in black pine could affect the antioxidant enzyme activity and the expression of phenylpropanoid metabolic pathway in host, which further affected the expression of susceptible symptoms. H2O2 production of enzyme sources found that xanthine oxidase (XO) inhibitor allopurinol and NADPH oxidase inhibitor diphenylene iodine (DPI) treatment can significantly inhibit H2O2 content in black pine, indicating that both XO and NADPH oxidase It is an important enzyme for the synthesis of endogenous H2O2 in the interactive system of Pinus thunbergii and Pine wood nematode.