Zinc finger-homeodomain (ZF-HDs) class IV TFs are plant-specific transcription factors that are essential for plant development, growth, and hormone signaling. Two new leaf rolling TFs genes, TaZHD1 and TaZHD10, were uncovered in wheat using comparative genomic analysis of the target region that housed a major QTL for leaf rolling revealed using multi-environment phenotyping and high throughput genotyping of a RIL population. The structural and functional analysis of putative ZHD genes in contrast to their rice orthologs demonstrates species-specific evolution and undoubtedly validates the hypothesis of remote-distance homology. The extreme RILs between the parental lines HD2012 and NI5439 displayed a significant variance in leaf rolling during the booting and heading stages, as per morphological evaluation. Transcriptome-wide expression profiling during drought stress revealed that TaZHD10 transcripts were substantially more expressed than TaZHD1 transcripts in all leaf tissues. The relative expression of these genes was validated by qRT-PCR analysis, which yielded consistent findings across all genotypes tested at the booting and anthesis stages. These genes are modulated differentially during drought conditions, which offers a lot of evidence for their epigenetic activity and may also demonstrate that they are modulated at the level of metabolic and gene regulatory networks. Utilizing miRNA prediction, five Tae-miRs were found that may be coupled to RNAi-mediated modulation of the TaZHD1 and TaZHD10 genes, which are believed to play a key role in the metabolic pathway controlling the rolled leaf phenotype. Interestingly, the TaZHD1 and TaZHD10 gene interaction networks also exhibited pleiotropic effects and may be involved in other functions in wheat aside from leaf rolling. Overall, the research expands our knowledge of TaZHD genes and might offer significant information for future functional genomics studies intended for developing leaf rolling-resistant cultivars by defining wheat breeding programs.
