State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100, China.
BMC Genomics. 2019 Aug 6;20(1):635. doi: 10.1186/s12864-019-5985-6.
As one of the most important transcription factor families, GRAS proteins are involved in numerous regulatory processes, especially plant growth and development. However, they have not been systematically analyzed in Brachypodium distachyon, a new model grass.
In this study, 48 BdGRAS genes were identified. Duplicated genes account for 41.7% of them and contribute to the expansion of this gene family. 33, 39, 35 and 35 BdGRAS genes were identified by synteny with their orthologs in rice, sorghum, maize and wheat genome, respectively, indicating close relationships among these species. Based on their phylogenic relationships to GRAS genes in rice and maize, BdGRAS genes can be divided into ten subfamilies in which members of the same subfamily showed similar protein sequences, conserved motifs and gene structures, suggesting possible conserved functions. Although expression variation is high, some BdGRAS genes are tissue-specific, phytohormones- or abiotic stresses-responsive, and they may play key roles in development, signal transduction pathways and stress responses. In addition, DELLA genes BdSLR1 and BdSLRL1 were functionally characterized to play a role in plant growth via the GA signal pathway, consistent with GO annotations and KEGG pathway analyses.
Systematic analyses of BdGRAS genes indicated that members of the same subfamily may play similar roles. This was supported by the conserved functions of BdSLR1 and BdSLRL1 in GA pathway. These results laid a foundation for further functional elucidation of BdGRAS genes, especially, BdSLR1 and BdSLRL1.
作为最重要的转录因子家族之一，GRAS 蛋白参与了许多调节过程，特别是植物的生长和发育。然而，它们在新型模式禾本科植物拟南芥中尚未得到系统分析。
本研究鉴定了 48 个 BdGRAS 基因。其中，复制基因占 41.7%，有助于该基因家族的扩张。通过与水稻、高粱、玉米和小麦基因组中的同源基因进行同线性分析，分别鉴定出 33、39、35 和 35 个 BdGRAS 基因，表明这些物种之间存在密切的关系。根据与水稻和玉米中 GRAS 基因的系统发育关系，BdGRAS 基因可分为 10 个亚家族，其中同一亚家族的成员具有相似的蛋白质序列、保守基元和基因结构，表明可能具有保守功能。尽管表达变异很大，但一些 BdGRAS 基因具有组织特异性、对植物激素或非生物胁迫的响应性，它们可能在发育、信号转导途径和应激反应中发挥关键作用。此外，通过 GA 信号通路，对 DELLA 基因 BdSLR1 和 BdSLRL1 的功能进行了特征分析，表明它们在植物生长中发挥作用，这与 GO 注释和 KEGG 途径分析一致。
对 BdGRAS 基因的系统分析表明，同一亚家族的成员可能发挥相似的作用。BdSLR1 和 BdSLRL1 在 GA 途径中的保守功能为这一观点提供了支持。这些结果为进一步阐明 BdGRAS 基因，特别是 BdSLR1 和 BdSLRL1 的功能奠定了基础。
