Genome-Wide Identification and Expression Profiling Analysis of the Xyloglucan Endotransglucosylase/Hydrolase Gene Family in Tobacco ( Nicotiana tabacum L.)

Xyloglucan endotransglucosylase/hydrolase genes ( ) encode enzymes required for the reconstruction and modification of xyloglucan backbones, which will result in changes of cell wall extensibility during growth. A total of 56 genes were identified from common tobacco, and 50 cDNA fragments were verified by PCR amplification. The 56 genes could be classified into two subfamilies: Group I/II and Group III according to their phylogenetic relationships. The gene structure, chromosomal localization, conserved protein domains prediction, sub-cellular localization of NtXTH proteins and evolutionary relationships among , , , , and rice were also analyzed. The expression profiles analyzed by the TobEA database and qRT-PCR revealed that display different expression patterns in different tissues. Notably, the expression patterns of 12 responding to environment stresses, including salinity, alkali, heat, chilling, and plant hormones, including IAA and brassinolide, were characterized. All the results would be useful for the function study of during different growth cycles and stresses.