Molecular Evolutionary Research Of The Plant XTH Gene Family And Preliminary Functional Analysis Of An AtXTH10 Gene In Arabidopsis

Xyloglucan endotransglycosylase/hydrolase(XTH)is an important cell wall modification enzyme,and it regulates the growth and differentiation of regulatory cells during morphogenesis and plays an important role in the physiological process of plant growth regulation.In this paper,127 potential members of the XTH gene family were identified from four plant species.Phylogenetic tree was then bulited for these XTH gene members,which were roughly divided into seven groups.Through comparing the maize XTH gene structure and protein motif composition,we found that the XTH gene family was highly homologous in each group.Chromosomal localization analysis of the maize XTHs showed that these genes distributed unevenly on 10 different chromosomes;Segmental and tandem duplications were probably important mechanism for their expansion.In the analysis of cis regulatory elements,we also found a wide range of elements involved in the regulation process of plant stress responses,especially for abscisic acid,drought and anoxic stress.Selection analysis also identified some positively selected sites that located on the ?-helix,?-turn and random coil regions of XTH protein.Expression levels of XTH genes were detected in 11 maize major organs and 60 specific tissues by microarray analysis.The result indicated that XTH genes were widely and differently expressed in various tissues.In addition,the activity analysis of AtXTH10 promoter showed that this gene was expressed in the flower,leaf vein,apex and terminal of the silique.To investigate the subcellular localization of AtXTH10 protein,the tobacco transient expression system and the onion epidermal cell expression system were used.The results indicated that AtXTH10 is mainly localized on the cell wall or cell membrane.The preliminary analysis of AtXTH10 gene function showed that the deletion and overexpression of this gene affect the growth and development of the plant roots through macroscopic and microscopic structure observation.Finally,we also studied the expression difference of several genes which were related to the growth of the Arabidopsis root in three plants(Col,atxth10 and AtXTH10-OE)by real-time PCR,and then speculated the potential position of AtXTH10 gene in the root development network.In this paper,we comprehensively studied the XTH family genes through bioinformatics and molecular experiments,which will provide a basis for the further molecular evolution and functional study of this gene family.