桃ACC合酶基因组DNA（pACSG01）的序列分析及其表达

以桃基因组DNA为模板，用套式PCR技术扩增并克隆了桃ACC合酶基因片段，将其克隆（定名为pACSG01）并进行序列测定，表明该自然全长1320bp，并富含HindⅢ和EcoRⅠ位点，与其它ACC合酶基因结构序列有一定的相似性，内含有两个内含子，编码的氨基酸序列与已克隆桃ACC合酶cDNA推导的氨基酸序列的同源性分别为57．4％和56．8％，pACSG01与我们已克隆的两个桃ACC合酶cDNA基因表达有所不同，RNA点杂交和RT－PCR结合Southern杂交分析表明，该基因在成熟和乙烯处理的果实均不表达，伤处理、LiCl和生长素处理也不能诱导核基因的表达，在衰老花瓣中也不表达，图3参18。

CLONING AND EXPRESSION OF PEACH 1-AMINOCYCLOPROPANE -1-CARBOXYLATE SYNTHASE GENOMIC DNA(pACSG01)

1-aminocylopropane-1-carboxylate (ACC) synthase is the key enzyme regulating ethylene biosynthesis in higher plants. Degenerated oligonucleotides to highly conserved regions of ACC synthase were used to prime the amplification of specific fragment by nested PCR in samples of peach genomic DNA. One fragment of about 1.3 kb was cloned and its complete nucleotide sequence was determined. The recombinant clone (pACSG01) contained a 1 320 bp insert which was rich in EcoRI and Hind Ⅲ sites. It was interrupted by two introns and was similar in gene structure with other ACC synthase gene. The predicted protein from its coding region was 57.4% and 56.8% identical to the deduced proteins from the peach ACC synthase cDNA. RNA dot blotting and RT-PCR combinated with southern blotting indicated that ACSG01 did not express in ripening and ethylene-treatment fruit. Wounding and LiCl and IAA treatment could not induced the accumulation of its mRNA in leaves and its mRNA could not accumulate in senescent petals. Fig 3, Ref 18