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以莲藕品种‘美人红’叶片为试材,利用RACE结合RT-PCR技术克隆得到全长4080 bp的莲藕可溶性淀粉合成酶基因(LrSSS)cDNA序列(Gen Bank登录号:KP201636),其中开放阅读框3696 bp,编码1231个氨基酸;该序列与甜瓜、葡萄SSS基因编码氨基酸序列同源性较高,分别达79%、69%。LrSSS所编码的氨基酸序列包含3个典型的碳水化合物结合结构域(CBM_25)和1个淀粉合成酶催化域(Glyco_transf_5)。LrSSS表达分析表明,莲藕根状茎膨大具3节段时,在终止叶叶片中的表达量最高,其次为后把叶叶片,终止叶叶柄表达量最少;在根状茎膨大至4节段时,LrSSS在第1、2节段根状茎中表达量较高,在第3、4节段根状茎中表达量较低,表明在第1、2节段根状茎形态基本建成后LrSSS在调控产物转化为淀粉过程中可能起到重要作用。
The full-length 4080 bp cDNA sequence of LrSSS (GenBank accession number: KP201636) was cloned by RACE and RT-PCR using lotus root ’Meirenhong’ as test material. The open reading frame 3696 bp, which encodes 1231 amino acids. This sequence has 79% and 69% homology with the SSS gene of melon and grape, respectively. The amino acid sequence encoded by LrSSS contains 3 typical carbohydrate-binding domains (CBM_25) and 1 starch synthase catalytic domain (Glyco_transf_5). LrSSS expression analysis showed that when rhizome was swollen with three segments, the expression level in the terminal leaf was the highest, followed by the lowest in the leaf and the terminal leaf petiole. When the rhizome enlarged to 4 segments , The expression of LrSSS was higher in the first and the second stage rhizomes and lower in the third and the third stage rhizomes, indicating that the LrSSS It may play an important role in regulating the conversion of products to starch.