title: Analysis of xyloglucan endotransglycosylase/hydrolase (XTH) genes and diverse roles of isoenzymes during persimmon fruit development and postharvest softening.
abstract: Xyloglucan endotransglycosylase/hydrolase (XTH) enzymes have played a role in the remodeling of cell wall hemicelluloses. To investigate the function of XTHs in persimmon (Diospyros kaki L.) fruit development and postharvest softening, five cDNAs (DkXTH1 to DkXTH5), whose putative proteins contained the conserved DEIDFEFLG motif of XTH, were cloned. Real time quantitative PCR analysis revealed that DkXTH1, DkXTH4, and DkXTH5 peaked in immature expanding fruit, and their higher expression was observed along with higher fruit firmness in cold-treated fruit or firmer cultivar fruit during storage. The opposite gene expression patterns were observed in DkXTH2 and DkXTH3, which reached maxima concomitance with pronounced fruit softening. Meanwhile, the xyloglucan endotransglycosylase (XET) enzymes play important roles in both the rapid growth and ripening of persimmon fruit. Furthermore, the recombined DkXTH1 and DkXTH2 proteins showed significant XET activity without any detected XEH activity. However, the XET activity of recombined DkXTH2 protein had a higher affinity for small acceptor molecules than that of recombined DkXTH1 protein. The former might prefer to participate in cell wall restructuring, and the latter is more inclined to participate in cell wall assembly. Besides, DKXTH proteins could function by targeting to the cell wall under regulation of a signal peptide. The data suggested that individual DKXTHs could exhibit different patterns of expression, and the encoded products possessed specific enzymatic properties conferring on their respective functions in growth and postharvest softening of persimmon fruit.
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Ye
authors: Y
authors: Han
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Qinggang
authors: Q
authors: Zhu
authors: College of Food Science and Technology, Hainan University, Haikou, P.R. China.
authors: Zhengke
authors: Z
authors: Zhang
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Kun
authors: K
authors: Meng
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Yali
authors: Y
authors: Hou
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Qiuyan
authors: Q
authors: Ban
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Jiangtao
authors: J
authors: Suo
authors: College of Horticulture, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors: Jingping
authors: J
authors: Rao
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D029788:Diospyros / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D005638:Fruit / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D010940:Plant Proteins; D016695:Glycosyltransferases; C473049:xyloglucan - xyloglucosyltransferase