Gene Family: Identification and Expression Profiles during Leaf Vein Development in Soybean.

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