Botticella Ermelinda, Pucci Anna, Sestili Francesco
Department of Agriculture and Forestry Sciences, University of Tuscia, Via S. Camillo de Lellis SNC, Viterbo, Italy.
J Plant Res. 2018 May;131(3):487-496. doi: 10.1007/s10265-017-1005-6. Epub 2017 Dec 19.
Starch synthase IIa, also known as starch granule protein 1 (SGP-1), plays a key role in amylopectin biosynthesis. The absence of SGP-1 in cereal grains is correlated to dramatic changes in the grains' starch content, structure, and composition. An extensive investigation of starch granule proteins in this study revealed a polymorphism in the electrophoretic mobility of SGP-1 between two species of wheat, Triticum urartu and T. monococcum; this protein was, however, conserved among all other Triticum species that share the A genome inherited from their progenitor T. urartu. Two different electrophoretic profiles were identified: SGP-A1 proteins of T. urartu accessions had a SDS-PAGE mobility similar to those of tetraploid and hexaploid wheat species; conversely, SGP-A1 proteins of T. monococcum ssp. monococcum and ssp. boeoticum accessions showed a different electrophoretic mobility. The entire coding region of the two genes was isolated and sequenced in an attempt to explain the polymorphism identified. Several single nucleotide polymorphisms (SNPs) responsible for amino acid changes were identified, but no indel polymorphism was observed to explain the difference in electrophoretic mobility. Amylose content did not differ significantly among T. urartu, T. monococcum ssp. boeoticum and T. monococcum ssp. monococcum, except in one accession of the ssp. boeoticum. Conversely, several interspecific differences were observed in viscosity properties (investigated as viscosity profiles using a rapid visco analyzer-RVA profiles) of these cereal grains. T. monococcum ssp. boeoticum accessions had the lowest RVA profiles, T. urartu accessions had an intermediate RVA profile, whereas T. monococcum ssp. monococcum showed the highest RVA profile. These differences could be associated with the numerous amino acid and structural changes evident among the SGP-1 proteins.
淀粉合酶IIa，也被称为淀粉颗粒蛋白1（SGP-1），在支链淀粉生物合成中起关键作用。谷物中SGP-1的缺失与谷物淀粉含量、结构和组成的显著变化相关。本研究对淀粉颗粒蛋白进行的广泛调查揭示了乌拉尔图小麦（Triticum urartu）和一粒小麦（T. monococcum）这两个小麦品种之间SGP-1电泳迁移率的多态性；然而，在所有其他从其祖先乌拉尔图小麦继承了A基因组的小麦品种中，这种蛋白质是保守的。鉴定出了两种不同的电泳图谱：乌拉尔图小麦材料的SGP-A1蛋白在SDS-PAGE中的迁移率与四倍体和六倍体小麦品种的相似；相反，一粒小麦（T. monococcum ssp. monococcum）和野生一粒小麦（T. monococcum ssp. boeoticum）材料的SGP-A1蛋白显示出不同的电泳迁移率。为了解释所鉴定的多态性，分离并测序了这两个基因的整个编码区。鉴定出了几个导致氨基酸变化的单核苷酸多态性（SNP），但未观察到插入缺失多态性来解释电泳迁移率的差异。除了野生一粒小麦的一个材料外，乌拉尔图小麦、野生一粒小麦和一粒小麦之间的直链淀粉含量没有显著差异。相反，在这些谷物的粘度特性（使用快速粘度分析仪-RVA图谱作为粘度曲线进行研究）方面观察到了几个种间差异。野生一粒小麦材料的RVA图谱最低，乌拉尔图小麦材料的RVA图谱居中，而一粒小麦的RVA图谱最高。这些差异可能与SGP-1蛋白中明显的大量氨基酸和结构变化有关。
