青藏高原青稞农家品种淀粉颗粒结合蛋白组成及GBSSI基因5′前导序列的多态性

Polymorphism of Starch Granule-Associated Proteins and 5' Leader Sequence of GBSSI Gene in Indigenous Naked Barley(Hordeum vulgare L.) from Qinghai-Tibetan Plateau in China

利用1D-SDS-PAGE分离了261份青藏高原农家青稞的淀粉颗粒结合蛋白,旨在为青藏高原青稞淀粉品质改良和淀粉颗粒结合蛋白机制研究提供依据和基础信息。在分子量45～100kD区域共有21种多态性蛋白条带和78种组合带型,其中2、3、5、10、11为新条带。利用PCR技术克隆了236份农家青稞GBSSI基因5′前导序列,出现1000bp和800bp的多态性片段,且以前者为主,其频率为80.1%。在8份农家青稞及4份引进的低直链淀粉材料的GBSSI基因5′前导序列中共检测到32个多态性位点,包括9个InDels和23个SNPs。GBSSI基因5′前导序列中出现了特有的序列差异,如未出现600bp类型(约400bp的特异缺失),而该缺失被认为是低直连淀粉大麦形成的原因;材料yf127、yf70、011Z1396和09Z586出现了特异点突变。因此认为,青藏高原农家青稞品种的淀粉颗粒结合蛋白具有丰富的多态性和独特性。低直链淀粉青稞GBSSI基因序列的新特征表明可能存在新的低直链淀粉形成机制。

Starch granule-associated proteins （SGAPs） are minor components tightly bound with starch granules, most of which are believed to be starch biosynthetic enzymes. We separated SGAPs from 261 indigenous naked barley accessions in Qing- hal-Tibetan Plateau of China using 1D-SDS-PAGE technique. A total of 21 polymorphic bands with molecular weights of 45-100 kD and 78 SGAPs patterns were detected, of which bands 2, 3, 5, 10, and 11 were novel protein bands. The 5＇ leader sequences of GBSSI gene were cloned using 236 accessions of indigenous naked barley. Two types of length polymorphisms （1 000 bp and 800 bp） were found with frequencies of 80.1% and 19.9%, respectively. According to sequencing results, there were 32 polymorphic sites in the 5＇ leader sequences of GBSS1 gene, including nine InDels and 23 SNPs. Specific mutations were found in Qing- hal-Tibetan Plateau accessions. For example, the 400 bp deletion reported corresponding to low amylose content in barley was absent in this study; and special SNPs were detected in accessions yf127, yf/0, 011Z1396, and 09Z586. These results imply that the SGAPs of the Qinghai-Tibetan Plateau indigenous naked barley are abundant and polymorphic. The novel sequence characteristics in the GBSS1 5＇ leader sequence of the low amylose accessions suggest a different mechanism for amylose biosynthesis in Qinghai-Tibetan Plateau indigenous naked barley.