Soybean Research Institute, National Center for Soybean Improvement, MOA Key Laboratory for Biology and Genetic Improvement of Soybean (General), National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, Jiangsu, China.
PLoS One. 2014 Jan 28;9(1):e87282. doi: 10.1371/journal.pone.0087282. eCollection 2014.
RBR (RING1-IBR-RING2) proteins play an important role in protein ubiquitination and are involved in many cellular processes. Recent studies showed plant RBR genes were induced by abiotic and biotic stresses. However, detailed studies on RBR genes in the important oil crop, soybean (Glycine max (L.) Merr.), is still lacking. Here we performed a genome-wide search and identified 24 RBR domain-containing genes from the soybean genome sequence and cloned 11 of them. Most soybean RBR proteins contain a highly conserved RBR supra-domain. Phylogenetic analyses indicated all 24 soybean RBR proteins are most related to the RBR proteins from Phaseolus vulgaris, and could be classified into seven groups including Ariadne A, Ariadne B, ARA54, Plant IIA, Plant IIB, Plant IIC, and Helicase. Tandem duplication and block duplication were found among the Ariadne B and Plant IIC group of soybean RBR genes. Despite the conserved RBR supra-domain, there are extensive variations in the additional protein motifs and exon-intron structures between different groups, which indicate they might have diverse functions. Most soybean RBR proteins are predicted to localize in nucleus, and four of them were experimentally confirmed by GFP fusion proteins. Soybean RBR genes are broadly expressed in many tissue types with a little more abundant in the roots and flowers than leaves, stems, and seeds. The expression of GmRTRTP3 (Plant IIB) and GmRTRTP5 (Plant IIC) are induced by NaCl treatment, which suggests these RBR genes might be involved in soybean response to abiotic stresses.
RBR（RING1-IBR-RING2）蛋白在蛋白质泛素化中发挥重要作用，并参与许多细胞过程。最近的研究表明，植物 RBR 基因受到非生物和生物胁迫的诱导。然而，关于重要油料作物大豆（Glycine max (L.) Merr.）中 RBR 基因的详细研究仍然缺乏。在这里，我们进行了全基因组搜索，从大豆基因组序列中鉴定出 24 个含有 RBR 结构域的基因，并克隆了其中的 11 个。大多数大豆 RBR 蛋白含有高度保守的 RBR 超结构域。系统发育分析表明，24 个大豆 RBR 蛋白与菜豆的 RBR 蛋白最为相关，可分为七个亚组，包括 Ariadne A、Ariadne B、ARA54、Plant IIA、Plant IIB、Plant IIC 和 Helicase。在大豆 RBR 基因的 Ariadne B 和 Plant IIC 亚组中发现了串联重复和块重复。尽管存在保守的 RBR 超结构域，但不同亚组之间的附加蛋白结构域和外显子-内含子结构存在广泛的变异，这表明它们可能具有不同的功能。大多数大豆 RBR 蛋白被预测定位于细胞核内，其中 4 个通过 GFP 融合蛋白得到了实验证实。大豆 RBR 基因在许多组织类型中广泛表达，在根和花中的表达量略高于叶、茎和种子。GmRTRTP3（Plant IIB）和 GmRTRTP5（Plant IIC）的表达受 NaCl 处理诱导，表明这些 RBR 基因可能参与了大豆对非生物胁迫的响应。
