Genome-wide elucidation and expression features of Q-type C2H2 zinc finger protein gene family in Rhododendron henanense subsp. lingbaoense

In plants, the C2H2 zinc-finger (C2H2-ZF) gene family is involved in various aspects of growth, development, and stress resistance. However, to date, no genome-wide identification, characterization, and expression analysis of C2H2-ZF genes have been reported in Rhododendron henanense subsp. lingbaoense (Rhl). The RhlC2H2 genes were identified using HMMER 3.0. Pfam and InterPro were used to determine the conserved domains. The phylogenetic trees of C2H2 genes were constructed by the neighbor-joining methods. The motif composition, chromosomal localization, and collinear relationship were analyzed by TBtools software. The tissue distributions and stress responses of RhlC2H2 genes were determined through RNA-seq or qRT-PCR technology. Overall, 77 RhlC2H2 genes were identified from the Rhl genome. According to the conserved motifs and gene structure, these RhlC2H2 genes could be classified into five subfamilies, RhlC2H2-I to V. A total of 7 pairs of tandem and 34 pairs of fragment genes were identified. Moreover, 83 cis-elements were predicted in the promoter regions of RhlC2H2 family genes, while the abiotic stress-responsive elements were present in almost all the RhlC2H2 genes. RNA-Seq revealed that RhlC2H2 family genes were differential distributed in root, stem, leaf, flower, and hypocotyl. qRT-PCR analysis revealed that four RhlC2H2 genes were responsive to abiotic stresses. The identification and characterization of RhlC2H2 genes revealed that several members may play critical roles in plant development and abiotic stress response. These data could lay foundations for the functional exploration of RhlC2H2 and further genetic breeding of Rhl with enhanced resistance to abiotic stresses.