Abstract
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.
Highlights
Transcription factors (TFs), as a special class of proteins with the activity of binding to specific regions of target gene promoters, play significant roles in plant growth and development, stress resistance, and signal transduction [1,2,3]
The proteins with an HD are classified into six subgroups according to the presence of structural differences: leucine zipper-associated HD (HD-ZIP), zinc finger motif-associated HD (ZF-HD), WUSCHELrelated homeobox (WOX), Bell-type HD, finger domain associated to a HD (PHD finger) and Knotted-related homeobox (KNOX) proteins [12]
A total of 32 Zinc finger homeodomain (ZF-HD) genes were identified in tobacco and designated NtZF-HD1 to NtZF-HD32 based on their physical locations on the chromosomes (Table S3)
Summary
Transcription factors (TFs), as a special class of proteins with the activity of binding to specific regions of target gene promoters, play significant roles in plant growth and development, stress resistance, and signal transduction [1,2,3]. Zinc finger homeodomain (ZF-HD) TFs usually include the following two structural features: a cysteine-rich zinc finger motif (ZF) and a conserved homeodomain (HD) [3]. ZFs contain zinc ions and cysteine residues or histidine residues [4]. The proteins with an HD are classified into six subgroups according to the presence of structural differences: leucine zipper-associated HD (HD-ZIP), zinc finger motif-associated HD (ZF-HD), WUSCHELrelated homeobox (WOX), Bell-type HD, finger domain associated to a HD (PHD finger) and Knotted-related homeobox (KNOX) proteins [12]
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