中文摘要：

叶绿体核糖体是植物特有的细胞器之一,其主要功能是合成质体基因编码的蛋白质.已有研究表明在叶绿体核糖体内含有6个质体特有蛋白PSRP （plastid-specific ribosomal protein）,分别命名为PSRP1~PSRP6.然而,这些蛋白在叶绿体蛋白合成过程以及光合作用中的作用机制研究尚处初级阶段.在本研究中,为了阐明PSRP-4蛋白在叶绿体发育过程中的作用机制,我们利用Gateway系统构建了Psrp-4基因（At2g38140）的RNAi表达载体,转化野生型拟南芥后获得了Psrp-4基因表达量明显降低的psrp-4突变体.研究结果表明：psrp-4突变体比野生型生长略微缓慢,但叶片颜色与野生型差别不大,能够进行正常的光合作用.在高光胁迫条件下,测定psrp-4突变体光合化学效率,发现与野生型差异不明显;进一步的蛋白免疫印记实验证明Psrp-4基因表达量的降低对PSⅡ反应中心D1蛋白的周转也没有明显影响.因此,推测PSRP-4蛋白可能不是叶绿体蛋白合成以及光合作用的正常进行所必需的.

英文摘要：

Chloroplast ribosome is an organelle which is specific to plants. Its main fimction is to synthetize proteins encoded by plastogenes. Study shows that chloroplast ribosome contains six PSRPs （plastid-specific ribosomal proteins）, named as PSRP1-PSRP6; however, the study on the functions of those proteins in photosynthesis and protein synthesis in chloroplast is still in its infancy. To investigate the roles of Psrp-4 in chloroplast development, RNAi vector ofPsrp-4 gene （A t2g38140） which was subsequently transformed into wild type Arabidopsis was constructed using Gateway technology, psrp-4 mutant showedsignificant reduction in expression level. Our results indicated that the growth rate ofpsrp-4 mutants was slightly lower than the wild type＇s; however, the leaf color of mutant and wild type plants were identical and photosynthesis in the mutant plants proceeded normally. Under high light treatment, photosynthesis efficiency of psrp-4 mutant plants was similar to that of wild-type plants. Further western blot analysis showed that the turnover rate of D1 protein, the PS II reaction center, was not significantly affected by the down-regulation of the Psrp-4 gene. The results above suggested that PSRP-4 might not play a pivotal role in protein synthesis or photosynthesis in chloroplast.