两个不同籽粒硬度小麦的比较蛋白组学分析

小麦是全球种植面积最大粮食作物,为全球45亿人提供日常蛋白和能量摄入的20%。弄清小麦籽粒硬度遗传基础,对于改良小麦品质具有重大意义。为探讨不同硬度小麦种子的分子基础,本实验选用西南麦区2个硬度差异极显著的小麦品种川麦66和蜀麦969,从蛋白水平上分析其种子蛋白差异表达情况,利用TMT定量蛋白质组学技术(tandem mass tags)结合生物信息学分析,分析差异表达的蛋白及其功能和通路等富集情况。结果表明,鉴定并定量了有效蛋白6020个,其中显著差异表达蛋白113个,在软质麦川麦66中上调表达的69个,下调表达的44个。差异蛋白GO富集分析共富集到65个GO条目,达到极显著富集水平的包括生物过程的1个条目、细胞组成的1个条目和分子功能的6个条目。推测营养库活性类蛋白、酶抑制剂活性类蛋白和谷胱甘肽代谢途径类蛋白可能参与小麦籽粒硬度形成。籽粒硬度相关蛋白可能主要分布于细胞胞外区,具有防御作用。从系统发育分析推测, puroindolines蛋白及其同源蛋白,可能既作为小麦籽粒贮藏蛋白,同时还能作为酶抑制剂调控籽粒发育。本研究为进一步探索小麦籽粒硬度遗传机制提供了参考。

Comparative proteomic analysis of two wheat genotypes with contrasting grain softness index

Wheat is the crop most widely grown in the world and provides the daily protein and 20% food calories for 4.5 billion people. It is crucial to understand the genetic basis of grain hardness for improving wheat quality. In order to explore the molecular basis of the formation of wheat grain hardness, two wheat cultivars Chuanmai 66 and Shumai 969 with significant hardness difference in southwest wheat region were selected to analyze the proteins differential expression by TMT quantitative proteomics (tandem mass tags) and bioinformatic methods of function and pathway enrichment analysis. A total of 6020 effective proteins were identified and quantified, including 113 differentially expressed proteins (DEPs), of which 69 were up-regulated and 44 were down-regulated in soft wheat Chuanmai 66. These DEPs were enriched into 65 GO terms, including a biological process term, a cellular component term and six molecular function terms at extremely significant level. Based on the enrichment analysis, we suggested that nutrient reservoir activity proteins, enzyme inhibitor proteins and glutathione metabolism proteins might participate in the formation of wheat grain hardness, and grain hardness related proteins might mainly distribute in the extracellular region of cells and had defensive function. According to the phylogenetic analysis, it was inferred that puroindolines and its homologous proteins might be as not only wheat grain storage proteins, but also enzyme inhibitors regulating grain development. This study provides a basis for further exploring the genetic mechanism of wheat grain hardness.