To better understand cytokinin signaling in melon (Cucumis melo L.), one of the most important fruit crops in the Cucurbitaceae family, we identified and characterized melon two-component system (TCS) genes in this study. The results showed that there were 51 genes encoding putative TCS proteins in melon, and these TCS genes were classified into 3 subgroups, with 17 HK(L)s (histidine kinase/histidine-kinase like; 9 HKs and 8 HKLs), 9 HPs (histidine phosphotransfer proteins; 6 authentic and 3 pseudo), and 25 RRs (response regulators; 8 Type-A, 11 Type-B and 6 pseudo). The identity values of these cytokinin signaling proteins were revealed by analyzing their conserved motifs, domains and amino acid sequences. By analyzing TCS genes in different plant species, we found that melon HK(L)s, HPs and RRs had closer phylogenetic relationships with cucumber genes than with the genes of other plants, and the expansion of melon cytokinin signaling genes might be attributed to segmental duplication events. Analysis of the putative promoter regions (2-kb upstream regions of the start codon) revealed the enrichment of stress- and hormone-response cis-elements. The involvement of these putative TCS genes in melon cytokinin signaling was further supported by qRT-PCR data.

中文翻译：

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瓜（Cucumis melo L.）中两组分系统（TCS）基因的全基因组表征。

为了更好地了解葫芦科植物中最重要的水果作物之一瓜（Cucumis melo L.）中的细胞分裂素信号传导，我们在本研究中鉴定并鉴定了瓜两组分系统（TCS）基因。结果表明，甜瓜中共有51个编码推定的TCS蛋白的基因，这些TCS基因被分为3个亚组，包括17个HK（L）s（组氨酸激酶/组氨酸激酶样； 9个HKs和8个HKLs），9个HPs。 （组氨酸磷酸转移蛋白； 6个真实的和3个假的），和25个RR（响应调节剂； 8个A型，11个B型和6个假）。通过分析它们的保守基序，结构域和氨基酸序列，揭示了这些细胞分裂素信号蛋白的身份值。通过分析不同植物物种中的TCS基因，我们发现甜瓜HK（L）s，HPs和RRs与黄瓜基因的亲缘关系比与其他植物的亲缘关系更密切，瓜类细胞分裂素信号传导基因的扩展可能归因于节段性复制事件。推定的启动子区域（起始密码子上游2 kb区域）的分析揭示了应激和激素反应顺式元件的富集。qRT-PCR数据进一步支持了这些推定的TCS基因参与瓜类细胞分裂素信号传导。