Rare Cold Inducible 2 (RCI2), also known as plasma membrane protein 3, is a group of low molecular weight proteins that play crucial roles in plant growth and development as well as environmental stress responses. In this work, we performed a comprehensive analysis of the RCI2 gene family and identified 4 RCI2 genes (CsaRCI2A–D) from cucumber (Cucumis sativus L.), which were distributed in four chromosomes of the cucumber genome. The amino acid identities among the 4 CsaRCI2 proteins varied from 46.55 to 76.00%. Phylogenetic analysis showed that RCI2 proteins from cucumber, Arabidopsis, Medicago truncatula, maize and rice could be classified into four distinct clades, and nearly all the RCI2 genes harbored two exons separated by an intron of variable size. Many development-, stress-, and hormone-related cis-elements were found in the promoter regions of the CsaRCI2 genes, and the CsaRCI2 genes seemed to have tissue-specific expression patterns. In addition, qRT-PCR analysis revealed that these four CsaRCI2 genes were all responsive to various abiotic stresses including cold, salt, and drought, as well as ABA treatment. Our findings lay a foundation for further elucidating the biological roles of the RCI2 gene family in cucumber.

中文翻译：

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黄瓜中罕见冷诱导型2（RCI2）基因家族的计算机鉴定和表达分析

罕见冷诱导型2（RCI2），也称为质膜蛋白3，是一组低分子量蛋白，在植物生长发育和环境胁迫响应中起着关键作用。在这项工作中，我们对RCI2基因家族进行了全面分析，并从黄瓜（Cucumis sativus L.）中鉴定了4个RCI2基因（CsaRCI2A – D），它们分布在黄瓜基因组的四个染色体中。4种CsaRCI2蛋白之间的氨基酸同一性从46.55％到76.00％不等。系统发育分析表明，RCI2蛋白来自黄瓜，拟南芥，紫花苜蓿。，玉米和水稻可分为四个不同的进化枝，几乎所有的RCI2基因都带有两个外显子，它们由一个可变大小的内含子隔开。在CsaRCI2基因的启动子区域发现了许多与发育，应激和激素相关的顺式元件，并且CsaRCI2基因似乎具有组织特异性的表达模式。此外，qRT-PCR分析显示这四个CsaRCI2基因均对各种非生物胁迫（包括冷，盐和干旱）以及ABA处理有反应。我们的发现为进一步阐明RCI2基因家族在黄瓜中的生物学作用奠定了基础。