Center of Excellence in Molecular Crop, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd., Wang Mai, Pathum Wan, Bangkok, 10330, Thailand.
Omics Sciences and Bioinformatics Center, Faculty of Science, Chulalongkorn University, 254 Phaya Thai Rd., Wang Mai, Pathum Wan, Bangkok, 10330, Thailand.
BMC Genomics. 2024 Oct 23;25(1):992. doi: 10.1186/s12864-024-10893-z.
Calmodulin-binding transcription activator (CAMTA) is comprised of a group of transcription factors and plays an important role in the Ca signaling pathway, mediating various molecular responses via interactions with other transcription factors and binding to the promoter region of specific genes. Mung beans (Vigna radiata) are one of the most commonly consumed commodities in Asia. To date, CAMTA proteins have not been characterized in this important crop plant.
Eight paralogous VrCAMTA genes were identified and found to be distributed on five of the 11 chromosomes. The proteins possessed CG-1 DNA-binding domains with bipartite NLS signals, ankyrin domains, CaM-binding IQ motifs, and CaM-binding domain (CaMBD). The 2 kb upstream regions of VrCAMTA genes contained sequence motifs of abscisic acid-responsive elements (ABRE) and ethylene-responsive elements (ERE), and binding sites for transcription factors of the bZIP and bHLH domains. Analysis of RNA-seq data from a public repository revealed ubiquitous expression of the VrCAMTA genes, as VrCAMTA1 was expressed at the highest level in seedling leaves, whereas VrCAMTA8 was expressed at the lowest level, which agreed with the RT-qPCR analysis performed on the first true leaves. On day four after leaf emergence, all VrCAMTA genes were upregulated, with VrCAMTA1 exhibiting the highest degree of upregulation. In darkness on day 4, upregulation was not observed in most VrCAMTA genes, except VrCAMTA7, for which a low degree of upregulation was found, whereas no difference was found in VrCAMTA8 expression between light and dark conditions. Treatment with calcium ionophores enhanced VrCAMTA expression under light and/or dark conditions at different times after leaf emergence, suggesting that calcium signaling is involved in the light-induced upregulation of VrCAMTA gene expression.
The expression dependence of nearly all VrCAMTA genes on light and calcium signaling suggests their possible differential but likely complementary roles during the early stages of mung bean growth and development.
钙调素结合转录激活因子（CAMTA）是一组转录因子，在钙信号通路中发挥重要作用，通过与其他转录因子相互作用并结合到特定基因的启动子区域，介导各种分子反应。绿豆（Vigna radiata）是亚洲最常食用的商品之一。迄今为止，CAMTA 蛋白尚未在这种重要的作物中得到描述。
鉴定出 8 个同源的 VrCAMTA 基因，它们分布在 11 条染色体中的 5 条上。这些蛋白质具有 CG-1 DNA 结合结构域和双部分 NLS 信号、锚蛋白结构域、钙调素结合 IQ 基序和钙调素结合结构域（CaMBD）。VrCAMTA 基因的 2kb 上游区域包含脱落酸反应元件（ABRE）和乙烯反应元件（ERE）的序列基序，以及 bZIP 和 bHLH 结构域转录因子的结合位点。对公共数据库中 RNA-seq 数据的分析表明，VrCAMTA 基因普遍表达，其中 VrCAMTA1 在幼苗叶片中表达水平最高，而 VrCAMTA8 表达水平最低，这与第一片真叶进行的 RT-qPCR 分析结果一致。在叶片出现后第四天，所有 VrCAMTA 基因均上调，其中 VrCAMTA1 的上调程度最高。在第四天黑暗条件下，除 VrCAMTA7 外，大多数 VrCAMTA 基因均未上调，VrCAMTA7 呈低度上调，而 VrCAMTA8 在光照和黑暗条件下的表达无差异。钙离子载体处理在叶片出现后不同时间增强了光照和/或黑暗条件下 VrCAMTA 的表达，表明钙信号参与了 VrCAMTA 基因表达的光诱导上调。
几乎所有 VrCAMTA 基因对光照和钙信号的表达依赖性表明，它们在绿豆生长发育的早期可能具有不同但可能互补的作用。
