Hooker Julia C, Smith Myron, Zapata Gerardo, Charette Martin, Luckert Doris, Mohr Ramona M, Daba Ketema A, Warkentin Thomas D, Hadinezhad Mehri, Barlow Brent, Hou Anfu, Lefebvre François, Golshani Ashkan, Cober Elroy R, Samanfar Bahram
Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada.
Department of Biology, Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON, Canada.
Front Plant Sci. 2023 Sep 18;14:1260393. doi: 10.3389/fpls.2023.1260393. eCollection 2023.
Soybean is an important global source of plant-based protein. A persistent trend has been observed over the past two decades that soybeans grown in western Canada have lower seed protein content than soybeans grown in eastern Canada. In this study, 10 soybean genotypes ranging in average seed protein content were grown in an eastern location (control) and three western locations (experimental) in Canada. Seed protein and oil contents were measured for all lines in each location. RNA-sequencing and differential gene expression analysis were used to identify differentially expressed genes that may account for relatively low protein content in western-grown soybeans. Differentially expressed genes were enriched for ontologies and pathways that included amino acid biosynthesis, circadian rhythm, starch metabolism, and lipid biosynthesis. Gene ontology, pathway mapping, and quantitative trait locus (QTL) mapping collectively provide a close inspection of mechanisms influencing nitrogen assimilation and amino acid biosynthesis between soybeans grown in the East and West. It was found that western-grown soybeans had persistent upregulation of asparaginase (an asparagine hydrolase) and persistent downregulation of asparagine synthetase across 30 individual differential expression datasets. This specific difference in asparagine metabolism between growing environments is almost certainly related to the observed differences in seed protein content because of the positive correlation between seed protein content at maturity and free asparagine in the developing seed. These results provided pointed information on seed protein-related genes influenced by environment. This information is valuable for breeding programs and genetic engineering of geographically optimized soybeans.
大豆是全球重要的植物性蛋白质来源。在过去二十年中，人们观察到一个持续的趋势：加拿大西部种植的大豆种子蛋白质含量低于加拿大东部种植的大豆。在本研究中，选取了10个平均种子蛋白质含量不同的大豆基因型，分别种植于加拿大东部的一个地点（对照）和西部的三个地点（试验）。测定了每个地点所有品系的种子蛋白质和油含量。利用RNA测序和差异基因表达分析来鉴定可能导致西部种植的大豆蛋白质含量相对较低的差异表达基因。差异表达基因在包括氨基酸生物合成、昼夜节律、淀粉代谢和脂质生物合成等本体和途径中富集。基因本体、途径映射和数量性状位点（QTL）映射共同对影响东部和西部种植的大豆之间氮同化和氨基酸生物合成的机制进行了仔细研究。研究发现，在30个单独的差异表达数据集中，西部种植的大豆中天门冬酰胺酶（一种天冬酰胺水解酶）持续上调，而天冬酰胺合成酶持续下调。由于成熟种子的蛋白质含量与发育种子中的游离天冬酰胺呈正相关，生长环境之间天冬酰胺代谢的这种特定差异几乎肯定与观察到种子蛋白质含量差异有关。这些结果提供了受环境影响的种子蛋白质相关基因的针对性信息。这些信息对于地理优化大豆的育种计划和基因工程具有重要价值。
