干旱胁迫下水稻生殖发育相关分析

【作者】 魏征；

【导师】 葛晓春；

【作者基本信息】 复旦大学 ， 生物化学与分子生物学， 2010， 硕士

【摘要】 水稻是我国乃至世界上最重要的粮食作物之一,具有突出的战略意义。近年来随着全球气候的剧变,干旱问题对水稻的正常生产活动产生越来越大的影响。花是水稻的生殖器官,其在干旱情况下的状态直接影响到水稻产量。以前大部分干旱研究集中于水稻营养期的根、叶等器官,而对于花器官应对干旱胁迫的研究甚少。我们通过对处于水稻减数分裂期前后的水稻进行干旱处理,收集处于不同发育时期的花,以正常生长情况下的花作为对照,通过基因芯片实验来调查水稻花的基因表达谱变化。通过多次生物学重复实验获得了大量的数据,对这些数据的分析整理发现,包括激素、能量代谢、生物胁迫等在内的多个信号转导途径受到影响,正负调控作用共同存在,从而使得胁迫下水稻花发育相关器官的形态以及育性异常。对处于减数分裂期前后的水稻3-5mm长度的花的三次基因芯片分析发现,在干旱胁迫下有339个基因的表达水平重复性地上调,118个基因表达水平重复性地下调。对于这些在三次实验中均重复出现的基因,我们按其生物学功能进行了归类,并对其进行了初步分析。结果显示,所发现的这些基因,部分已被验证确实与干旱胁迫相关,有一部分基因则是首次发现；另外一些基因则显示出在于旱过程的多重角色,有些既参与了信号转导也参与了代谢,可能对水稻的生殖发育产生影响。这些基因成为我们的关注点,可能对于改善干旱胁迫下的水稻生殖发育具有重要的作用。通过Real-Time PCR对部分基因的表达水平验证证明了芯片数据的可靠性。在此基础上,挑选了部分基因进行克隆,通过转基因手段来验证它们是否有助于改善干旱胁迫下的水稻育性。更多还原

【Abstract】 Rice is one of the most important crops in china and even in the world. In recent years, drought has caused severe rice yield loss, especially in those water-deficit areas.Improving rice growth and development under drought stress is important for maintaining grain yield,Previous research mainly focus on the effect of drought on root and leaf development during vegetative growth stage. However, flower, as the reproductive organ, will directly affect the grain production. It remains unclear how rice floral organs respond to water-deficit condition and therefore alter the reproductive development.Our research aims to understand the molecular mechanisms regulating this process, and finally to improve rice yield under drought stress.Responses of rice florets to drought stress at the molecular level around meiosis stage were studied in order to obtain candidate genes which can improve rice drought tolerance. We treated the rice plants at early reproductive stages with less water than normal, then hold the same SRWC (soil relative water content) for about seven days. After that, we collected the drought-treated and control rice flowers according to the the length of florets. RNA is extracted for microarray analysis. By analysis of the microarray data, we found that some genes and pathways have been induced or inhibited under drought stress, suggesting that the cell status of rice florets, such as energy metabolism, oxireduction status have been altered. The gene-chip analysis experiments were repeated in triplicate.339 genes were found to be repeatedly up-regulated and 118 genes down-regulated under drought stress.We further classify these genes according to their GO and annotations, as well as the information from published papers. The results show that some of the genes have already been reported to be involved in drought resistance, and others are new. Some genes are involved in multiple pathways such as cell metabolism and flower developement.More experiments will be necessary to further characterize their roles under drought stress.Real-Time PCR was used to confirm the microarry data,and the results are generally consistent. Based on the analysis results, several genes were chosen for further identification. Overexpression of these genes in rice flowers will allow us to understand if they can improve rice reproductive development under drought condition.更多还原