水稻胚乳贮藏物代谢相关基因响应花后高温胁迫的微阵列分析

【目的】揭示花后高温条件下水稻灌浆过程中胚乳淀粉和蛋白贮藏物代谢相关基因的表达谱,并阐明部分重要功能基因对花后高温胁迫的响应表达模式。【方法】利用人工气候箱设高温(日均温度32℃,日最高温36℃/日最低温28℃)和适温(日均温度22℃,日最高温26℃/日最低温18℃)2个温度处理,并在水稻开花后的不同时期取样,对水稻胚乳贮藏物代谢各类相关基因的表达谱与表达模式进行高通量的cDNA微阵列检测。【结果】在水稻胚乳贮藏物代谢的相关基因中,以对高温胁迫响应表现较迟钝的基因居多,其高温处理与低温处理之间的杂交信号(nARVOL)比值(称R值)大致在0.8—1.2,但随高温处理时间的持续,呈上调或下调差异表达的基因数量均有明显增加;花后高温对胚乳糖代谢和淀粉合成类基因表达的调控效应,不仅随各个基因的功能类型、代谢途径和灌浆进程的差别变化而异,而且其表达丰度及其上调或下调幅度在很大程度上还与该功能基因的同工型(或酶亚基)有关;高温处理下水稻胚乳中的谷蛋白、醇溶蛋白和球蛋白类基因多呈下调表达特征,但也会随其所调控的蛋白亚基组分的不同而异,从而对胚乳贮藏蛋白的亚基构成和组分变化产生较大影响;与胚乳白贮藏物代谢密切相关的糖信号传导类基因、核糖体蛋白类基因和逆境防御蛋白类基因普遍比直接参与胚乳贮藏物合成路径的功能基因对高温胁迫响应表现敏感。【结论】花后高温胁迫对水稻胚乳灌浆贮藏物代谢的调控相当复杂,涉及到众多的功能基因位点。

Microarray Analysis of Gene Expression Profile Related to Grain Storage Metabolism in Rice Endosperms as Affected by High Temperature at Filling Stage

[Objective]Effects of high temperature after rice flowering stage on the expression profile and their patterns of mass genes related to grain storage membolism were clarified.[Method]A cDNA array of 3574 unigenes containing was used for the detection of different filling grain samples and the controlled temperature treatments were conducted in growth chambers,with the daily mean temperature being controlled at 32℃(36℃/28℃)and 22℃(26℃/18℃)for high and moderate temperatures,respectively.[Result]The expression levels of majority genes were not sensitive to high temperature treatment among 657-673 candidate genes,with their R value (the ratio of gene hybridized signal between two temperature treatments) ranging from 0.8 to 1.2. However,the different expression genes (up-regulation or down-regulation) increased remarkably when rice plants were consistently exposed to high temperature treatment.There was a considerable difference in gene expression patterns of grain starch synthesis and carbohydrate metabolism induced by high temperature treatment after flowering stage,varied greatly with different gene function classification,metabolizing pathway,iso-form types(or subunit)and also fdling stage,in which such genes imposing sugar signal function, with much wide variation in expression levels between two temperature treatment, were more sensitive to high temperature than those genes in relation with grain starch synthesis and other carbohydrate metabolism. The expressing response of storage protein genes to high temperature was mostly down-regulation, despite different patterns for some protein subunit. For all genes related to grain protein synthesis metabolism, these genes impacting ribosomal protein and defense protein synthesis were mostly sensitive to different temperature treatments or strongly-high specific expression induced by high temperature at filling stage. [Conclusion] There is a complex regulating network existing in the effects of high temperature stress on mass genes related to grain storage metabolism, with many genes being probably regulated by high temperature.