荞麦属种间13S球蛋白基因序列比较研究

荞麦13S球蛋白是荞麦种子中的一类主要贮藏蛋白。本研究选用荞麦属植物甜荞栽培种及其野生类型、苦荞栽培种及其野生类型、毛野荞、左贡野荞、细柄野荞和硬枝万年荞6个种共44份材料,进行PCR特异性扩增、测序得到荞麦13S球蛋白基因的保守片段序列。对序列进行差异分析,结果发现44份供试材料13S球蛋白基因片段的285个排列位点中不变位点为24个,多态性位点S为261个(含简约信息位点数198个和单型可变位点63个),序列总突变位点Eta为503个。野生甜荞种内13S球蛋白基因序列差异明显高于栽培甜荞,但野生苦荞种内13S球蛋白基因序列差异仅稍高于栽培苦荞。推测其一方面可能与繁殖方式有关,另一方面可能与荞麦驯化过程中通常只有少数野生型群体被驯化有关。系统聚类分析发现栽培甜荞与野甜荞亲缘关系近,与左贡野荞亲缘关系次之;栽培苦荞与野苦荞亲缘关系近,与毛野荞亲缘关系次之;细柄野荞和硬枝万年荞的13S蛋白基因片段序列差异较小,说明其亲缘关系较近。上述结果为荞麦属种间遗传多样性与进化关系研究提供了理论依据。

Sequence Analysis of 13S Globulin Geneof Genus Fagopyrum Species

13S globulin is one of the major storage proteins in buckwheat seeds. This study investigated the 13S globulin gene sequence by PCR specific amplification and sequencing using 6 species of genus Fagopyrum, a total of 44 collections including cultivated and wild species of F. esculentum and F. tataricum, F. pilus, F. zuogongense, F. gracilipes, F. urophyllum. Variance analysis of ultra-conserved segments of 13S globulin gene sequence indicated that a total of 285 arrangement sites (excluding deletion and insertion loci) were identified including 24 invariable (monomorphic) sites and 261 polymorphic (segregating) sites (198 parsimony informative sites and 63 singleton variable sites), and a total of 503 mutations on Eta site were isolated in the whole sequence. The intraspecific genetic diversity of 13S globulin gene sequence for the wild species of common buckwheat was obviously higher than that of the cultivated species of common buckwheat, and for the wild species of tartary buckwheat was slightly higher than that of the cultivated species of tartary buckwheat,cultivated species of tartary buckwheat was higher than common buckwheat. However, a lower intraspecific genetic diversity of 13S globulin gene sequence for was found in wild species of tartary buckwheat when compared to wild species of common buckwheat. These results implied that the distinct genetic diversity of 13S globulin gene sequence between F. esculentum and F. tataricum might be due to the fact that only a few wild type groups were domesticated during evolution as well as the different reproductive patterns. artificial domestication leaded to a severe narrow of genetic diversity of 13S globulin gene sequence in common buckwheat with cross-pollination characteristics during evolution. Cluster analysis indicated that the cultivated species of F. esculentum was closely clustered with its wild species, and further grouped with F. zuogongense, while the cultivated species of F. tataricum was closely clustered with its wild species, and further grouped with F. pilus. The highly ultra-conserved gene sequence of 13S globulin of F. gracilipes and F. urophyllum was identified, implying a close relationship between F. gracilipes and F. urophyllum. These results provide the theoretical basis for research of genetic diversity and evolutionary relationship of genus Fagopyrum.