茶树CsSMT基因的单核苷酸多态性及其表达

Single Nucleotide Polymorphism and Expression Analysis of CsSMT Gene in Tea Plant

为了发掘利用茶树茶树富硒关键酶硒代半胱氨酸甲基转移酶(Selenocysteine methyltransferase,SMT)基因CsSMT,通过RACE克隆该基因的cDNA全长,并通过水培试验,分析该基因在井43幼苗根叶的表达特征。结果表明:通过该基因cDNA的全长克隆,获得5个茶树品种CsSMT的开放阅读框(ORF)全长;对茶树5个品种的ORF核苷酸多态性鉴定共检测到19个多态性位点,包括17个SNPs和2个InDels,平均每55 bp检测到1个多态性位点,这些多态位点引起9个氨基酸位点变化;5个茶树品种SMT的氨基酸序列一致性为99.15%,出现一定的遗传分化。Na_2SeO_3水培及荧光定量PCR表明,CsSMT基因在茶树幼苗根与成熟叶中均有表达;Na_2SeO_3显著诱导成熟叶中该基因表达,抑制须根CsSMT表达。

The present study was conducted to explore the selenocysteine methyltransferase （SMT） gene CsSMT, which played an essential role in tea plant leaves enriching selenium. The whole cDNA was obtained by RACE cloning. Based on solution culture experiments, expres- sion patterns of CsSMT in Long, in 43 were analyzed. Results ： Through cloning the whole CsSMT cDNA in five tea cultivars, their open read- ing frame （ORF） was obtained. By polymorphism identification of SMT gene ORF for the five tea cultivars, 19 polymorphisrn sites were i- dentified, including 17 single nucleotide polymorphisms （SNPs） and two InDels （insertion and deletion） with the polyrnorphism frequency of 1/55 bp. These polymorphism sites caused nine amino acid positions change. Amino acid sequence identification of SMT was 99.15 % in five tea cultivars, with a certain genetic distribution. Solution culture and the real-time PCR analysis showed that CsSMT transcripts in ma- ture leaves were significantly increased upon the treatment of Na2 SeO3 , while the opposite trend was observed in fibrous roots.