Characterization and expression of WAG-2 transcripts in a wheat three-pistil mutant line

Аннотация

The common wheat (Triticum aestivum L.) three-pistil (TP) mutant produces three pistils in a floret, consequently, forms three grains after pollination. It has potential to increase yields and also a significant genetic material to study floral development. Research on the genetic mechanisms determining of TP floral organ development has a potential prospect for wheat breeding. In this study, four WAG-2 transcripts, named WAG-2l, WAG-2m, WAG-2n and WAG-2o were isolated from TP and characterized. They were highly conserved in the MADS-domain and I-region while two distinct sequence divergences were detected in K-domain and C-region. The four WAG-2 transcripts could be divided into two groups resulted from splicing events with alternative 5′ splice site selection of exon 4. The expression levels of each WAG-2 transcript in Chinese Spring (CS) were approximately 1.5 and 74.5-fold higher than that in near-isogenic CSTP lines derived from wheat three-pistil mutant/Chinese Spring)//Chinese Spring. At anther separation stage, WAG-2n (the splicing variant 2) played a vital role in CS, while WAG-2m (the splicing variant 1) was highly expressed in CSTP. The alteration of expression of four WAG-2 transcripts were at least partly associated with the threepistil trait. The expression levels of four WAG-2 transcripts were highest at anther separation stage to tetrad stage, particularly in pistil development suggesting that they function in pistil development and maturation rather than in differentiation. These findings enrich the understanding of the molecular mechanism controlling the TP trait and WAG-2 gene function.