柿果实ACC合成酶cDNA的克隆及其序列分析

根据其它植物ACC合成酶（1－aminocyclopropane-1-carboxylic acid synthase,ACS)氨基酸保守区，设计1组简并引物，用RT－PCR法，从柿（Diospyros kaki Thunb.)果实扩增出3个约1kb左右的cDNA片段，将其克隆至pGEM-T载体上，对这些重组克隆进行序列测定和氨基酸序列推导，DK－ACS1由1101个碱基组成，编码364个氨基酸；DK－ACS2是1086个碱基，编码359个氨基酸；DK－ACS3为1089个碱基，编码363个氨基酸。它们均具有其它植物ACS合成酶中存在的7个保守区和11个不变氨基酸残基，且在多肽水平上有较高的同源性。与番茄LE－ACS2的同源性DK－ACS1是60.5A%,DK-ACS2是70.7%,DK－ACS3为66．9％，与甜瓜CM－ACS1的同源性依次分别是60．4％，72．1％和64．4％。

Cloning and sequence analysis of cDNA encoding for ACC synthase from persimmon fruit

According to the amino acid conserved region of ACC synthase (1-aminocyclopropane-1-carboxylic acid synthase,ACS) from other plant,a group of degeneracy primers were designed in this paper.Three cDNA fragments about 1 kb were amplified and cloned into pGEM-T vector from persimmon (Diospyros kaki Thunb.) fruit by RT-PCR.The result of sequencing and amino acid squence inference of these recombinant plasmid shows:DK-ACS1 has 1101 bases,encoding 364 amino acid,DK-ACS2 has 1086 bases,encoding 359 amino acid;and DK-ACS3 has 1098 bases,encoding 363 amino acid.They also have 7 conserved regions and 11 constant amino acid residues of ACC synthase gene that existing in other plant,and with higher identity in polypeptide level.The amino acid sequence of DK-ACS1,DK-ACS2 and DK-ACS3 are 60.5%,70.7% and 66.9% indential to LE-ACS2 from tomato;and are 60.4%,72.1% and 67.4% indentical to CM-ACS1 from melon,respectively.