甜橙柠檬酸合酶基因的克隆及其在果实发育过程中的表达分析

柠檬酸合酶与柠檬酸的积累密切相关，通过分析其与酸含量的关系，为研究该基因的调控机制奠定理论基础。设计特异性引物对柠檬酸合酶基因进行克隆，并采用半定量PCR法对哈姆林叶片、果肉和果皮中该基因的表达模式进行检测。克隆得到柠檬酸合酶基因的cDNA序列，全长1535bp，ORF区含471个氨基酸残基，序列比对显示，哈姆林甜橙柠檬酸合酶基因与其他植物的该基因高度同源。半定量PCR结果显示果肉和果皮中柠檬酸合酶基因在各个时期的表达基本没有变化，而叶片中其表达水平随果实发育成熟不断降低，与果实中柠檬酸含量变化趋势相同。说明叶片中柠檬酸合酶基因表达与果实酸含量正相关。

Cloning of citrate synthase gene and expression during the fruit development in Orange

As a key enzyme of citrate metabolism, citrate synthase shows a close relationship with the accumulation of citrate. In order to investigate the expression mode of citrate synthase gene, the cDNA encoding citrate synthase was cloned from Hamlin leaf by PCR. It was 1535 bp long and encoded a protein with 471 amino acids. Alignment analysis showed that citrate synthase gene had high homology with other plants. The samples were collected in four different periods after flowering. The expression of citrate synthase gene had no obvious change in flesh and peel of different periods, while was decreased during the development which had an identitcal tendency with the change of the amount of citrate.