竹类植物Dwarf 14(D14)基因的多态性分析

Polymorphisms of Dwarf 14(D14) Gene in Bambusoideae

独脚金内酯(SL)是一种新型的植物激素,可调控植物分枝。DWARF14(D14)蛋白可作为该激素受体,也可以在该激素信号传导过程中起一定作用。为研究D14基因与竹类植物地下茎类型的相关性,通过基因克隆和生物信息学手段,分析具有不同地下茎类型(散生型、丛生型和混生型)的17种竹种材料中该基因序列变异。结果表明,各竹种中D14基因均含有2个外显子和1个内含子,序列间同源性为92.57%,c DNA序列的同源性为98.97%,氨基酸序列的同源性为98.61%。所编码的蛋白序列均含催化中心的保守氨基酸(Ser147、Asp268和His297)及包裹SL裂解物的氨基酸残基(Phe186、Val194、Trp205、Tyr209、Phe245和Ser270)。DNA序列富含单核苷酸多态性(SNP)位点,SNP的频率为1SNP/22 bp,多样性指数πCDS为0.01476。其中,7个SNP位点能将丛生竹与其他2个类型的竹区分开来。基于D14基因的基因组序列所构建的系统进化树基本能反映供试材料的地下茎类型,该研究有助于了解竹类植物不同地下茎类型的分子差异,为提高竹笋产量提供了理论依据。

Strigolactone（ SL） is a new plant hormone which regulates shoots branching. DWARF14（ D14） may act as SL receptor,and is also involved in the signal transduction pathway of SL. In order to analyze the correlation between D14 gene and the underground rhizome type,the sequence variations of the gene were investigated in 17 bamboo species that are grouped into scattered,mixed and sympodial bamboos based on their underground rhizome type. All examined orthologous D14 geneswere consisted of two exons and one intron. The DNA,c DNA and amino acid sequences of 17 orthologous D14 genes werefound to have 92. 57%,98. 97% and 98. 61% identities,respectively. Their encoded protein sequences contained the catalytic amino acid residues（ Ser147,Asp268 and His297） and those amino acid residues（ Phe186, Val194, Trp205, Tyr209, Phe245 and Ser270） surrounding the catalyzed substance. The phylogenetic tree based on the D14 gene sequences was generally consistent with the underground rhizome types. The DNA sequences were rich in single nucleotide polymorphism（ SNP） sites. The SNP frequency was 1/22,and the nucleotide diversity（ π） equaled 0. 01476. Seven SNPs were informative in relation to the sympodial bamboos. Real time PCR showed that the expression level of D14 gene was not related to the underground rhizome type. The study can help to recognize the molecular diversity of different underground rhizome types in bamboo and it is the theoretical basis for increasing yields of bamboo shoots. It laid a foundation for further understanding of D14 in the regulation pathway of branching.