Yang Yating, Yuan Zhuo, Ning Conghui, Zhao Baoling, Wang Ruoruo, Zheng Xiaoling, Liu Yu, Chen Jianghua, He Liangliang
School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
CAS Key Laboratory of Topical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China.
Front Genet. 2022 Jul 6;13:936051. doi: 10.3389/fgene.2022.936051. eCollection 2022.
Pea ( L.) is one of the most important legume crops in the world, and it has attracted great attention for its high nutritive values. Recently, the crop breeding program has been focused on the crop metabolic engineering (i.e., color, flavor, nutrition) to improve the quality of crop. As a major group of transcription factors forming the ternary MYB-bHLH-WD repeat protein (MBW) complex to regulate the anthocyanin biosynthesis pathway, members of gene family have always been the focus of research targets to improve the valuable metabolic product of crops. Until now, few report about the gene family of pea has been released. In this study, we identified 119 genes in the assembled pea genome (Version 1a), of which 111 were distributed across 14 chromosomes. Combining with the 126 R2R3-MYB protein sequences of , we categorized 245 R2R3-MYB proteins into 36 subgroups according to sequence similarity and phylogenetic relationships. There was no member from subgroup 12, 15 and 29 existing in pea genome, whereas three novel subgroups were found in pea and named as N1-N3. Further analyses of conserved domains and Motifs, gene structures, and chromosomal locations showed that the typical R2 and R3 domains were present across all R2R3-MYB proteins, and Motif 1, 2, and 3 were identified in most members. Most of them had no more than two introns. Additionally, 119 pea genes did not experience large-scale duplication events. Finally, we concluded that several candidate genes may be responsible for the spatiotemporal accumulation of anthocyanins in pea petals. was predominantly expressed in the dorsal petals to presumably activate the anthocyanin biosynthesis pathway, while and may positively regulates the anthocyanin accumulation in the lateral petals. This study not only provides a good reference to further characterize the diverse functions of R2R3-MYB genes but also helps researchers to understand the color formation of pea flowers.
豌豆（L.）是世界上最重要的豆科作物之一，因其高营养价值而备受关注。近年来，作物育种计划一直聚焦于作物代谢工程（即颜色、风味、营养）以提高作物品质。作为形成三元MYB-bHLH-WD重复蛋白（MBW）复合体以调控花青素生物合成途径的主要转录因子群体，该基因家族的成员一直是改善作物有价值代谢产物的研究目标焦点。到目前为止，关于豌豆该基因家族的报道很少。在本研究中，我们在组装的豌豆基因组（版本1a）中鉴定出119个该基因，其中111个分布在14条染色体上。结合该物种的126个R2R3-MYB蛋白序列，我们根据序列相似性和系统发育关系将245个R2R3-MYB蛋白分为36个亚组。豌豆基因组中不存在第12、15和29亚组的成员，而在豌豆中发现了三个新的亚组并命名为N1-N3。对保守结构域和基序、基因结构及染色体定位的进一步分析表明，所有R2R3-MYB蛋白都存在典型的R2和R3结构域，并且在大多数成员中鉴定出了基序1、2和3。它们大多数含有不超过两个内含子。此外，119个豌豆该基因未经历大规模复制事件。最后，我们得出结论，几个候选基因可能负责豌豆花瓣中花青素的时空积累。该基因主要在背瓣中表达，可能激活花青素生物合成途径，而另外两个基因可能正向调节侧瓣中的花青素积累。本研究不仅为进一步表征R2R3-MYB基因的多种功能提供了良好参考，也有助于研究人员了解豌豆花的颜色形成。
