COMPARATIVE PROTEOMIC ANALYSIS OF THE THICK-WALLED RAY FORMATION PROCESS OF HALOXYLON AMMODENDRON IN THE GURBANTUNGGUT DESERT, CHINA

Abstract

Thick-walled ray cells of Haloxylon ammodendronwere first reported by Zhou and Gong in 2017, but their formation mechanism remains unknown. In this study, we performeda proteomic analysis of ray cell wall formation in the xylem. H. ammodendronin Shihezi exhibits a thicker ray cell wall than that in Jinghe. During the process of cell wall biosynthesisin the xylem of H. ammodendron, the nonspecific lipid-transfer protein and beta expansin EXPB2.1 (Mirabilis jalapa) first loosen the cell wall, and this step is followed by extension and expansion. Subsequently, xyloglucan endotransglycosylase/hydrolase 1 cleaves and linksthe xyloglucan chains. Photosystem I P700 apoprotein A1, reversibly glycosylated polypeptide 1 and GDP-mannose-3′,5′-epimerase are involved in the cellulose, hemicellulose and pectin biosynthesis processes in the cell wall by providing components or energy. Finally, the proteins involved in phenylpropanoid biosynthesis promote lignification of the ray cell wall and complete the biosynthetic process of the cell wall.