The type-B authentic response regulators (ARR-Bs) function as positive regulators of cytokinin signal transduction and play important roles in abiotic stress resistance and plant development. However, little of ARR-B family is known in tomato. In this study, we performed a comprehensive analysis of ARR-B family factors in tomato. In total, 12 genes encoding ARR-B transcription factors (named as SlARR-B1-SlARR-B12) were identified from tomato. We analyzed the structures, chromosome locations, phylogeny, protein motifs, and expression profiles of these SlARR-B genes. Gene structure analysis showed that 5-12 exons and 4-11 introns existed in the SlARR-B genes. These SlARR-B genes were asymmetrically distributed on eight chromosomes in tomato. Phylogenetic tree of SlARR-B genes from tomato and other plant species revealed that SlARR-B genes were classified into 6 subfamilies. SlARR-B proteins had typical conserved domains, including Motif 1 and Motif 2. The investigation of the expression profiles of SlARR-B genes in all the examined tissues demonstrated that these genes were differentially expressed, including roots, stems, leaves, flowers, and fruits at developmental stages. Notably, the expression of SlARR-B11 and SlARR-B12 exhibited high expression levels in flowers. Each gene was induced by at least one of different phytohormones (SA, IAA, ABA, IBA, 6-BA, JA, GA, and ETH) and four abiotic stress treatments (heat, drought, salt, and cold). This study sets a good foundation for further characterization of the SlARR-B transcription factors in plant development and abiotic stress responses of tomato.

中文翻译：

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番茄中 SlARR-B 基因家族的全基因组鉴定、基因组组织和表达谱。

B 型真实反应调节剂 (ARR-Bs) 作为细胞分裂素信号转导的正调节剂发挥作用，在非生物胁迫抗性和植物发育中发挥重要作用。然而，在番茄中对 ARR-B 家族知之甚少。在这项研究中，我们对番茄中的 ARR-B 家族因子进行了综合分析。总共从番茄中鉴定了12 个编码 ARR-B 转录因子的基因（命名为SlARR-B1 - SlARR-B12）。我们分析了这些SlARR-B基因的结构、染色体位置、系统发育、蛋白质基序和表达谱。基因结构分析表明，SlARR-B基因中存在5-12个外显子和4-11个内含子。这些SlARR-B基因在番茄的八条染色体上不对称分布。来自番茄和其他植物物种的SlARR-B基因的系统发育树显示SlARR-B基因分为 6 个亚科。SlARR-B 蛋白具有典型的保守结构域，包括 Motif 1 和 Motif 2。对所有检查组织中SlARR-B基因表达谱的调查表明，这些基因差异表达，包括根、茎、叶、花和发育阶段的果实。值得注意的是，SlARR-B11和SlARR-B12的表达在花中表现出高表达水平。每个基因由至少一种不同的植物激素（SA、IAA、ABA、IBA、6-BA、JA、GA 和 ETH）和四种非生物胁迫处理（热、干旱、盐和冷）诱导。该研究为进一步表征番茄植物发育和非生物胁迫响应中的SlARR-B转录因子奠定了良好的基础。