Zinc finger homeodomain (ZF-HD) transcription factors play significant roles in plant growth and responses to environmental stresses. In this study, 32 ZF-HD genes identified in the tobacco (Nicotiana tabacum L.) genome were divided into six groups according to phylogenetic analysis with Arabidopsis and tomato ZF-HD members. An examination of gene structures and conserved motifs revealed the relatively conserved exon/intron structures and motif organization within each subgroup. In addition, various stress-related elements are found in the promoter region of these genes. The expression profiling analysis revealed that NtZF-HD genes expressed in different tissues and could be induced by several abiotic stresses. Notably, NtZF-HD21 was highly expressed in response to the drought treatments. Subcellular localization analysis and a virus-induced gene silencing (VIGS) experiment were performed to investigate the potential functions of NtZF-HD21. The subcellular localization indicated that NtZF-HD21 is a nuclear protein. Furthermore, gene silencing of the NtZF-HD21 gene reduced the drought resistance of tobacco. These findings provide insights for further biological functional analyses of the NtZF-HD genes in tobacco.

中文翻译：

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烟草中ZF-HD基因家族的系统研究揭示了其在非生物胁迫中的多重作用

锌指同源结构域（ZF-HD）转录因子在植物生长和对环境胁迫的响应中起重要作用。在这项研究中，根据拟南芥和番茄ZF-HD成员的系统发育分析，在烟草（Nicotiana tabacum L.）基因组中鉴定的32个ZF-HD基因被分为六个组。对基因结构和保守基序的检查揭示了每个亚组内相对保守的外显子/内含子结构和基序组织。另外，在这些基因的启动子区域发现了各种与压力相关的元件。表达谱分析表明，NtZF-HD基因在不同的组织中表达，并可能受到多种非生物胁迫的诱导。尤其，NtZF-HD21在干旱处理中高表达。进行了亚细胞定位分析和病毒诱导的基因沉默（VIGS）实验，以研究NtZF-HD21的潜在功能。亚细胞定位表明NtZF-HD21是一种核蛋白。此外，NtZF-HD21基因的基因沉默降低了烟草的抗旱性。这些发现为进一步研究烟草中NtZF-HD基因的生物学功能提供了见识。