Molecular characterization of the TaWTG1 in bread wheat (Triticum aestivum L.)

OsWTG1 (LOC_Os08g42540.1) functions as an important factor determining grain size and shape in rice. Our understanding on its ortholog in wheat, TaWTG1, is limited. Here, we identified and mapped TaWTG1 in wheat, characterized its gene and protein structures, predicted transcription factor binding sites of its promoter, and the expression patterns was also analysed bases on real-time quantitative PCR and public available microarray data. The WTG1 orthologs in barley (HvWTG1), rice (OsWTG1), Aegilops tauschii (AtWTG1), Triticum urartu (TuWTG1), Triticum turgidum (TtWTG1) and Brachypodium distachyon (BdWTG1) were also identified for comparative analyses. TaWTG1 was mapped onto the short arms of group 7 chromosomes (7AS, 7BS, and 7DS). Multiple alignments indicated that WTG1 possesses eight exons and seven introns in all of the orthologs, except for the orthologs on 7A of wild emmer and on 7D of A. tauschii (seven exons and six introns). An exon-intron junction composed of intron 2 to intron 3 and exon 2 to exon 4 was highly conserved. The protein of WTG1 exists a conserved domain (Peptidase_C65). WTG1 was mainly expressed in wheat roots, spikes and grains, in barley caryopsis and roots, and in rice anthers. Drought and heat stresses significantly regulated the expression of TaWTG1 in wheat. In barley, WTG1 was significantly down-regulated under Fusarium at late stage. In addition, significant correlations between the expression patterns of predicted transcription factors and WTG1 were also detected. Overall, the results presented here broaden our knowledge on WTG1 and will be helpful for its manipulation aiming at dissecting its function in plants.