Systematic Investigations of the ZF-HD Gene Family in Tobacco Reveal Their Multiple Roles in Abiotic Stresses

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.