Grain size is an important trait for crops. The endogenous hormones brassinosteroids (BRs) play key roles in grain size and mass. In this study, we identified an ethyl methylsulfonate (EMS) mutant wheat line, SM482gs, with increased grain size, 1000-grain weight, and protein content, but decreased starch content, compared with the levels in the wild type (WT). Comparative transcriptomic analysis of SM482gs and WT at four developmental stages [9, 15, 20, and 25 days post-anthesis (DPA)] revealed a total of 264, 267, 771, and 1038 differentially expressed genes (DEGs) at these stages. Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis showed that some DEGs from the comparison at 15 DPA were involved in the pathway of “brassinosteroid biosynthesis,” and eight genes involved in BR biosynthesis and signal transduction were significantly upregulated in SM482gs during at least one stage. This indicated that the enhanced BR signaling in SM482gs might have contributed to its increased grain size via network interactions. The expression of seed storage protein (SSP)-encoding genes in SM482gs was upregulated, mostly at 15 and 20 DPA, while most of the starch synthetase genes showed lower expression in SM482gs at all stages, compared with that in WT. The expression patterns of starch synthase genes and seed storage protein-encoding genes paralleled the decreased level of starch and increased storage protein content of SM482gs, which might be related to the increased seed weight and wrinkled phenotype.

颗粒大小是作物的一个重要性状。内源性激素油菜素内酯 (BRs) 在颗粒大小和质量中起关键作用。在本研究中，我们鉴定了甲基磺酸乙酯 (EMS) 突变小麦品系SM482gs，与野生型 (WT) 相比，其颗粒大小、千粒重和蛋白质含量增加，但淀粉含量降低。SM482gs的比较转录组分析和 WT 在四个发育阶段 [开花后 9、15、20 和 25 天 (DPA)] 在这些阶段共发现了 264、267、771 和 1038 个差异表达基因 (DEG)。京都基因和基因组百科全书 (KEGG) 数据库分析显示，在 15 DPA 比较的一些 DEG 参与了“油菜素类固醇生物合成”的途径，并且至少在SM482gs中，参与 BR 生物合成和信号转导的 8 个基因显着上调。一个阶段。这表明SM482gs中增强的 BR 信号可能通过网络相互作用导致其晶粒尺寸增加。种子贮藏蛋白 (SSP) 编码基因在SM482gs中的表达表达上调，主要在 15 和 20 DPA，而与 WT 相比，大多数淀粉合成酶基因在SM482gs中的所有阶段都表现出较低的表达。淀粉合酶基因和种子贮藏蛋白编码基因的表达模式与SM482gs淀粉水平降低和贮藏蛋白含量增加平行，这可能与种子重量增加和皱缩表型有关。