苦荞和甜荞查尔酮合成酶基因的克隆及序列比较

Cloning and Sequence Comparison of CHS Gene from Tartary Buckwheat (Fagopyrum tataricum) and Common Buckwheat (Fagopyrum esculentum)

以苦荞品种‘西农9920’和甜荞品种‘西农9976’为材料,根据其它植物查尔酮合成酶(chalcone synthase,CHS)基因DNA序列的保守区域设计的一对简并引物,进行PCR扩增,从2种荞麦基因组中克隆出了长度均为860 bp的CHS基因片段,对其进行回收、克隆,挑选阳性克隆测序;序列分析表明这2个片段含有CHS基因的N端和C端的结构域,分别为苦荞和甜荞的CHS基因片段,命名为FtCHS和FeCHS。对获得的2种荞麦CHS基因的DNA序列进行比较分析,发现两者间存在多达43处单碱基多态性,这些单碱基多态性可能是苦荞和甜荞种子中类黄酮含量差异的重要原因之一。苦荞和甜荞CHS与其它植物CHS的氨基酸序列的进化分析表明,其与同为蓼科的掌叶大黄和石竹科的满天星的同源性较近。

Degenerate primers designed from the conservative domain of Chalcone Synthase （CHS） in plants were used to amplify the CHS fragments from genomic DNA of tartary buckwheat （Fagopyrum tataricum Gaertn. ） cultivar ＇Xinong 9920＇ and common buckwheat （Fagopyrum esculentum Moench） cultivar ＇Xinong 9976＇ ;A single 860 bp fragment was amplified from both tartary buckwheat and common buckwheat, respectively. The amplified fragments were then collected, cloned and sequenced. Sequence analysis indicated there was the typical domains of N-terminal and C-terminal of CHS in those two fragments,designated as FtCHS and FeCHS for tartary buckwheat and common buckwheat,respectively. Comparison on the nucleotide sequence of FtCHS and FeCHS revealed 43 single nucleotide polymorphisms,which may be one of the major reasons leads to the difference of flavonoids contents in seeds between tartary buckwheat and common buckwheat. Phylogenic analysis on the amino acid sequence of CHS from tartary buckwheat and common buckwheat with some other plants showed that tartary buckwheat and common buckwheat were closely related to Rheum palmatum and Gypsophila paniculata.