Genome-wide analysis of zinc finger motif-associated homeodomain (ZF-HD) family genes and their expression profiles under abiotic stresses and phytohormones stimuli in tea plants ( Camellia sinensis )

In plants, zinc finger motif-associated homeodomain (ZF-HD) transcription factors (TFs) play indispensable roles in developmental processes and stress responses. However, the specific functions of members of the ZF-HD gene family in tea plants ( Camellia sinensis ) are poorly understood. We identified 18 CsZF-HD genes in tea at the whole-genome scale. These genes were phylogenetically classified into two major subfamilies: ZF-HD and MIF. Gene structural analyses showed that 13 of the 18 members have no introns. Analysis of transcriptome data revealed different spatio-temporal expression patterns of CsZF-HD genes in various tissues. On the basis of the cis -acting elements analysis, we detected the expression patterns of CsZF-HD genes under various abiotic and phytohormone treatments (drought, cold, exogenous SA, MeJA, ABA, and GA 3 ). Quantitative real time polymerase chain reaction (qRT-PCR) analyses confirmed the differential expression of CsZF-HDs under diverse stress and phytohormone treatments. The miRNAs that regulate CsZF-HD genes and their endogenous target mimics (eTMs) were predicted and investigated. The expression patterns of CsZF-HD10 and csn-miR172b-5p-3 were completely opposite under salicylic acid treatment. We also detected negative regulatory relationships between csn-miR2673a and CsZF-HD15 under salicylic acid treatment, between csn-miR399a-5 and CsZF-HD9 under abscisic acid treatment, and between csn-miR2673a and CsZF-HD3 under methyl jasmonate treatment during most sequential stages. The results indicate that the predicted eTM (LTCONS-00,013,981) of csn-miR2673a may indirectly modulate CsZF-HD expression by baiting relevant miRNAs under salicylic acid treatment. Together, these results lay the foundation for further research on the biological functions of CsZF-HDs.