琯溪蜜柚CmPME1的克隆及其在果实发育过程中的表达分析

利用RT-PCR技术从‘琯溪蜜柚’中克隆得到1条PME（pectinmethylesterase）基因的ORF序列，命名为CmPME1。该序列编码一个含有582个氨基酸的蛋白质，分子量63.37 ku，该蛋白属于稳定的碱性亲水性蛋白。同源性分析表明：其编码的氨基酸序列与可可树（Theobroma cacao）、毛果杨（Populus trichocarpa）的同源性分别为76％、74％，与甜橙的氨基酸序列同源性高达99％。实时荧光定量PCR结果表明，随着果实的发育，CmPME1的表达量逐渐升高，在花后170 d达到最高，然后逐渐降低，远中柱汁胞CmPME1的表达量高于近中柱。

Cloning and Expression Analysis of CmPME1 During Fruit Development of Citrus maxima(Burm.)Merr.

The ORF of PME gene was cloned from Citrus maxima(Burm.)Merr. by RT-PCR, and it was named as CmPME1. The CmPME1 encods a protein with 582 amino acids. The deduced protein molecular weight was 63.37 ku and it was a stable alkaline hydrophilic protein. The deduced amino acid sequence of CmPME1 showed high identity with that of other plants, for instance CmPME1 shared 76% homology with PME protein of Theobroma cacao, 74% homology with PME protein of Populus trichocarpa and 99% homology with PME protein of Citrus sinensis. The result of real-time fluorescence quantitative PCR analysis showed during fruit development, CmPME1 expression level rose at first, and reached the highest amount at 170 days after flowering, then reduced gradually. The study also indicated the expression level of CmPME1 in juice sac away from the column was higher than in juice sac near the column.