Abstract
Xyloglucan endotransglucosylases/hydrolases (XTHs) are a class of enzymes capable of catalyzing the molecular grafting between xyloglucans and/or the endo-type hydrolysis of a xyloglucan molecule. They are encoded by 33 genes in Arabidopsis, and are divided into three subfamilies. Members of Group III subfamily are implicated in hydrolysis of xyloglucans, but their physiological roles remain elusive. We analyzed expression and function of all members of this subfamily (AtXTH27,-28,-29,-30,-31,-32,-33). Morphology of T-DNA-insertion lines for these XTH genes was indistinguishable from that of the wild type, except for the xth27 mutant, indicating that these XTHs are functionally redundant. To investigate their roles in more detail, we generated 20 double mutants. Promoter GUS expression analyses have shown that some of these genes are co-expressed temporally in specific plant tissues. Double mutation of XTH27 and XTH28, which are both expressed in anther, conferred a short-silipue phenotype.
