Abstract: Xyloglucan endotransglucosylase/hydrolases (XTH) belongs to glycoside hydrolase, family 16 (GH16) and it is a class of enzymes that mediate the construction and recombination of xyglucan-cellulose skeleton. To explore the potential biological functions of XTH family genes in Antirrhinum majus. In this paper, bioinformatics analysis, RNA-seq analysis and qRT-PCR were used to investigate the expression levels of the family genes in the petalized and non-petalized stamens and disease-resistant materials. The results showed that the main conserved motif from 33 identified AmXTH proteins was ExDxE, which could be divided into 3 subgroups. Most of the cis-acting elements of AmXTH promoter are growth and development, disease resistance and stress resistance. RNA-seq and qRT-PCR revalidation finally unearthed four positive candidate genes (AmXTH3, 14, 18, and 33) and one candidate genes (AmXTH23) for nagatively mediated Sclerotinia sclerotiorum resistance. There were 12 positive AmXTH candidate genes (AmXTH1, 7, 9, 11, 21, 22, 23, 24, 26, 28, 29 and 33) and 2 negative AmXTH candidate genes (AmXTH15 and 31). Among them, AmXTH23 and 33 may play a role in both of the A. majus resistant to S. sclerotiorum and stamen petalization. In this study, the candidate AmXTH genes involved in S. sclerotiorum resistance and stamen petalization of A. majus were preliminarily excavated, which laid a foundation for further revealing the gene function.

Key words: Antirrhinum majus, xyloglucan endotransglucosylase/hydrolases family, Sclerotinia sclerotiorum resistance, stamen petalization, differential gene expression