新疆冬小麦地方品种高分子量麦谷蛋白亚基的地理分布及其新发现亚基的特性(英文)

Geographical Distribution of High-Molecular-Weight Glutenin Subunits and Characterization of a New High-Molecular-Weight Glutenin Subu nit of Winter Wheat Landraces(Triticum aestivum L.)in the Xinjiang Uygur Autonomous District of China

【目的和方法】为了揭示新疆小麦地方品种高分子量谷蛋白亚基（HMW—GS）的遗传多样性，对新疆北部地区（北疆）、东部地区（东疆）和南部地区（南疆）小麦地方品种HMW—GS的分布进行了研究。【结果】研究表明：新疆小麦地方品种HMW—GS等位变异的分布与其地理来源具有密切关系，除Glu-B1位点外，G2u—A1和Glu—D1位点等位变异在北部地区、东部地区和南部地区的分布频率存在显著差异。在Glu—A1位点，Glu—A1c编码的Null亚基出现的频率最高，其次是Glu—A1b编码的2^＊亚基；但在北部地区，几乎所有品种都含有Glu—A1c编码的Null亚基，仅有1个品种含有Glu—A1b编码的2^＊亚基。在Glu-81位点，新疆大多数小麦地方品种含有Glu—B1b编码的7＋8亚基。在Glu—D1位点，新发现的等位基因Glu—D16p（t）编码的2．6亚基在东疆和南疆出现的频率较高，但在北疆出现的频率最低，分别为91％（东疆），61％（南疆），19％（北疆）；等位基因Glu—D1bp（t）在南疆冬小麦地方品种中普遍存在。然而，北疆是以等位基因Glu—D1a编码的2＋12亚基为主，其频率为83％。关于Glu—D1bp（t）的起源，推测可能是在南疆地区自然突变产生，然而由于南疆和东疆荒漠化造成的地理阻碍使其向北疆传播的概率较低，同时抑制了该基因向东亚地区的迁移。【结论】基于DNA序列的氨基酸序列比对，发现Glu—D1bp（t）编码的2．6亚基与Glu—D1al编码的2．2^＊亚基非常相似。

[ Objective and Method ] We studied the regional distribution of high - molecular - weight glutenin subunit （ HMW - GS ） alleles （ Glu - 1 ） in common wheat landraces with winter habit in the northern, the eastern and the southern regions in the Xinjiang- Uygur Autonomous District （Xinjiang） in China. [ Result] The investigation of regional differences in allele frequencies of the three loci affecting HMW - GS revealed that regional differences were not statistically significant for the Glu - B1 locus, but significant for the Glu -A1 and Glu -D1 loci. As for the Glu -A1 locus, the allele frequency of Glu -Alc encoding the null subunit was the highest, followed by Glu -A1 b encoding the subunit 2^＊ throughout the district, but in the northern region, all cultivars harbored Glu -A1c except only one cuhivar with Glu -A1b. At the Glu -B1 locus, most of Xinjiang landraces had Glu -Blb encoding the subunit pair 7 ＋ 8. At the Glu -D1 locus, the reeendy identified allele Glu - D1bp （t） encoding the subunit pair 2.6 ＋ 12 was distributed in higher frequencies in the eastern and the southern regions but less frequent in the northern region. Its frequencies were 17% , 91% and 66% in northern, eastern and southern regions, respectively. In the southern region, the majority of landraces had Glu - D1 bp （t） throughout the region. In the northern region, however, the majority （83%） of the allele was Glu -Dla encoding the subunit pair 2 ＋ 12. Regarding to the origin of Glu -D1bp （t）, the new allele might appear by a spontaneous mutation and become a major allele by a bottleneck effect caused by the afterward occurring desertification in the southern and the eastern regions, and a few cuhivars were thought to bc spread to the northern region, but landraces with this allele to be not transferred to East Asia. [ Conclusion ] Based on the comparison of amino acid sequences deduced from DNA sequence, we found that the subunit 2.6 encoded by Glu - D1 @ （t） had very high similarity with the subunit 2.2^＊ encoded by Glu - D1 al.