稻瘟病菌分泌小蛋白对氮素营养的响应

Response of Small Proteins Secreted by Rice Blast (Magnaporthe oryzae) to Nitrogen Nutrition

病原菌在侵染寄主过程中会经历氮饥饿的过程,而在这一过程中有大量的寄主植物和病原菌基因表达。为了明确稻瘟菌分泌蛋白基因的表达是否受外界不同氮源的影响,本研究开展了稻瘟病菌预测小分泌蛋白在不同氮源及稻瘟病菌与水稻互作中的表达。首先利用生物信息学软件分析稻瘟病菌基因组,选择了12个预测的小分泌蛋白编码基因。利用Real-time RT-PCR分析这12个基因在完全培养基、1/10-氮和氮饥饿培养基培养的菌株中及受侵染水稻中的表达。表明除MGS1242外,其余11个小分泌蛋白基因的表达不受外界氮源的影响。MGS1242在经1/10-氮和氮饥饿培养24 h和48 h时的两个菌株中的表达量明显上调、在稻瘟病菌株侵染水稻24 h和48 h时有大幅度上调,72 h时表达量开始逐渐下降。因此MGS1242可作为一个氮调控相关的基因进行深入研究。由此可以看出,稻瘟病菌大部分分泌小蛋白基因的表达不受外界氮营养的影响,但它们能被稻瘟病菌侵染水稻过程中被诱导表达,分析这些蛋白的编码基因在完全培养、1/10-氮处理、氮饥饿处理下和稻瘟病菌侵染水稻不同时期的相对表达量变化,以明确稻瘟病菌小蛋白基因对氮营养的敏感性,通过本研究的开展可为今后对病原菌适应缺氮环境下的生存和发育研究提供重要参考。

Pathogenic bacteria undergo nitrogen starvation in the process of infecting hosts,and in the process a large number of host plant and pathogen genes are expressed.In order to determine whether the expression of the secreted protein gene of Magnaporthe grisea is influenced by different nitrogen sources,this study carried out the research of Magnaporthe grisea to predict the expression of small secreted proteins in different nitrogen sources and the interaction between Magnaporthe grisea and rice.First,bioinformatics software was used to analyze the genome of M.grisea,and 12 predicted small secreted proteins were selected.The 12 genes were analyzed by real-time RT-PCR in fcomplete cultured medium,1/10-nitrogen and nitrogen starvation medium and in infected rice.The results showed that except for MGS1242,the expression of the other 11 small secreted proteins was not affected by the external nitrogen sources.The expression of MGS1242 was significantly up-regulated in two strains cultured for 24 h and 48 h with 1/10-nitrogen and nitrogen starvation,significantly up-regulated in rice blast induced by rice blast at 24 h and 48 h,began to gradually decline.Therefore MGS1242 can be used as a nitrogen regulation related gene for further study.Futhermore,it can be seen that the expression of most of the small-protein genes secreted by Magnaporthe grisea was not influenced by outside nitrogen nutrition,but they can be induced to express in rice infected with Magnaporthe grisea.The genes encoding these proteins were analyzed in complete culture,1/10-N treatment,nitrogen starvation and rice blast infection rice at different stages of the relative expression changes in order to clarify the sensitivity of rice blast protein genes to nitrogen nutrition,through the development of this study for the future.It provided an important reference for the study of survival and development of pathogenic bacteria in the environment of nitrogen deficiency.