Abstract:

【Objective】 Effects of high temperature after rice flowering stage on the expression profile and their patterns of mass genes related to grain storage metabolism 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 filling 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.

Key words: rice (Oryza sativa L.), high temperature, gene expression, cDNA-microarray, grain storage metabolism