HD-Zip III Gene Family: Identification and Expression Profiles during Leaf Vein Development in Soybean

Abstract

Leaf veins constitute the transport network for water and photosynthetic assimilates in vascular plants. The class III homeodomain-leucine zipper (HD-Zip III) gene family is central to the regulation of vascular development. In this research, we performed an overall analysis of the HD-Zip III genes in soybean (Glycine max L. Merr.). Our analysis included the phylogeny, conservation domains and cis-elements in the promoters of these genes. We used the quantitative reverse transcription-polymerase chain reaction to characterize the expression patterns of HD-Zip III genes in leaf vein development and analyze the effects of exogenous hormone treatments. In this study, twelve HD-Zip III genes were identified from the soybean genome and named. All soybean HD-Zip III proteins contained four highly conserved domains. GmHB15-L-1 transcripts showed steadily increasing accumulation during all stages of leaf vein development and were highly expressed in cambium cells. GmREV-L-1 and GmHB14-L-2 had nearly identical expression patterns in soybean leaf vein tissues. GmREV-L-1 and GmHB14-L-2 transcripts remained at stable high levels at all xylem developmental stages. GmREV-L-1 and GmHB14-L-2 were expressed at high levels in the vascular cambium and xylem cells. Overall, GmHB15-L-1 may be an essential regulator that is responsible for the formation or maintenance of soybean vein cambial cells. GmREV-L-1 and GmHB14-L-2 were correlated with xylem differentiation in soybean leaf veins. This study will pave the way for identifying the molecular mechanism of leaf vein development.

Genome-Wide Characterization and Expression Profiling of HD-Zip Genes in ABA-Mediated Processes in Fragaria vesca

“…One HD-Zip II gene has been reported to positively regulate peach fruit ripening [ 16 ]. HD-Zip III genes are mainly involved in embryogenesis [ 20 ], meristem function [ 21 , 22 ], and vascular development [ 20 , 23 ]. HD-Zip IV genes are shown to be mainly involved in epidermal cell differentiation, anthocyanin accumulation, root development, and trichome formation as well as reproductive growth [ 24 , 25 , 26 ].…”