Genome-wide characterization of the xyloglucan endotransglucosylase/hydrolase family genes and their response to plant hormone in sugar beet.

Xyloglucan endotransglucosylase/hydrolases (XTHs) play a crucial role in plant growth and development. However, their functional response to phytohormone in sugar beet still remains obscure. In this study, we identified 30 putative BvXTH genes in the sugar beet genome. Phylogenetic and evolutionary relationship analysis revealed that they were clustered into three groups and have gone through eigh t tandem duplication events under purifying selection. Gene structure and motif composition analysis demonstrated that they were highly conserved and all contained one conserved glycoside hydrolase family 16 domain (Glyco_hydro_16) and one xyloglucan endotransglycosylase C-terminus (XET_C) domain. Transcriptional expression analysis exhibited that all BvXTHs were ubiquitously expressed in leaves, root hairs and tuberous roots, and most of them were up-regulated by brassinolide (BR), jasmonic acid (JA), abscisic acid (ABA) and gibberellic acid (GA 3). Further mutant complementary experiment demonstrated that expression of BvXTH17 rescued the retarded growth phenotype of xth22 , an Arabidopsis knock out mutant of AtXTH22. The findings in our work provide fundamental information on the structure and evolutionary relationship of the XTH family genes in sugar beet, and reveal the potential function of BvXTH17 in plant growth and hormone response. • A total number of 30 BvXTH genes were identified in the sugar beet genome. • Eight tandem duplication events occurred in BvXTH gene family. • All BvXTHs were ubiquitously expressed in leaves, root hairs and tuberous roots. • Most BvXTHs showed responsive expression to BR, JA, ABA and GA 3. • BvXTH17 is a functional orthologue of AtXTH22 in sugar beet. [ABSTRACT FROM AUTHOR]