野生大豆与栽培大豆rDNA ITS1区的研究

STUDIES ON rDNA ITS1 REGIONS OF SOYBEAN AND ITS WILD RELATIVES

采用ＰＣＲ 技术从野生大豆（Ｇｌｙｃｉｎｅ ｓｏｊａ）、半野生大豆（Ｇ．ｇｒａｃｉｌｌｉｓ）、多年生野生大豆（Ｇ．ｔｏｍｅｎｔｅｌｌａ、Ｇ．ｔａｂａｃｉｎａ）和栽培大豆（Ｇ．ｍ ａｘ）的两个品种ＵＮＩＯＮ、文丰７ 中扩增和克隆了ｒＤＮＡ第一转录间隔区（ＩＴＳ１）。其在Ｇ．ｍ ａｘ 基因组中的拷贝数约为２×１０３。序列分析表明Ｇ．ｓｏｊａ、Ｇ．ｇｒａｃｉｌｌｉｓ、Ｇ．ｍ ａｘ 中的Ｇ／Ｃ含量为６１．４０％ ，而Ｇ．ｔａｂａｃｉｎａ和Ｇ．ｔｏｍ ｅｎｔｅｌｌａ的Ｇ／Ｃ含量分别为５８．１１％ 和５９．０１％ ，与绿豆Ｇ／Ｃ含量（５９．８１％ ）相近。Ｇ．ｔａｂａｃｉｎａ的Ｇ／Ｃ含量是已知的植物中ＩＴＳ１ 最低的。最大同源性分析表明，大豆属植物ＩＴＳ１ 的同源程度很高，同其近缘属绿豆的同源性明显高于其它作物。同时分析了栽培、多年生和一年生野生大豆间的亲缘关系。另外还发现在已知的植物ＩＴＳ１ 序列中均含有ＧＡＣＣＣＧＣＧＡＡ 及ＧＣＧＣＣＡＡＧＧＡＡ

The rDNA internal transcribed spacer 1 (ITS1) regions of wild soybean (Glycine soja), semiwild soybean (G.gracillis), perennial wild soybean (G.tomentella, G.tabacina) and two accessions of cultivated soybean (G.max) were amplified by PCR and cloned.The copy number in soybean genome was about 2×10 3.Sequence analysis showed that the G/C content of G.soja(61 40%), G.gracillis(61 40%), G.max(61 40%), G.tabacina (58 11%) and G.tomentella (59 01%) were very similar to that of Phaseolus radiatus (59 81%), and the G/C content of G.tabacina was the lowest one in all known ITS1 regions of plants.Maxium homology analysis proved that the ITS1 sequence of soybean was the most homologous to its counterpart of P. radiatus.It was implied that the homology of ITS1 regions of relative species were related with the genetic relationships among these species.Sequence analysis disclosed that there were two conserved sequences (GACCCGCGAA) and (GCGCCAAGGAA) in all sequenced ITS1 regions of plants.