Characterization and expression profile analysis of YABBY family genes in Pak-choi (Brassica rapa ssp. chinensis) under abiotic stresses and hormone treatments

Abstract

YABBY proteins are widely distributed among different plant species and exhibit a higher degree of prevalence in angiosperms than in gymnosperms; abaxial cell fate in the lateral organs of plants is mainly determined by the functions of YABBY genes. However, to date, no scientific study has been conducted on the functions and responses of these genes under different forms of abiotic stresses in Pak-choi (Brassica rapa ssp. chinensis). In this study, we cloned and identified 12 YABBY family genes from Pak-choi. The evolutionary history of the YABBY genes was studied in nine species and showed that YABBY gene loss occurred during specific periods or in certain species during evolution. The putative YABBY family genes of Pak-choi were comprehensively analyzed by comparison with the corresponding orthologs in Arabidopsis and Chinese cabbage (Brassica rapa ssp. pekinensis) and classified into five subfamilies based on the specific protein domains and phylogenetic clades. A subcellular localization assay involving BcYABBY1b and BcYABBY2c confirmed that the BcYABBY proteins were localized in the nucleus. qRT-PCR data revealed that the BcYABBY genes are specifically expressed in distinct organs and developmental stages. Furthermore, the expression profiles of the BcYABBY genes were investigated under different hormone treatments and abiotic stress factors. In this study, we comprehensively identified and analyzed the YABBY gene family in the Pak-choi genome. Our data provide possible functional information regarding the involvement of BcYABBY genes in plant growth and development and in the response to abiotic stress and hormone treatments.