Identification And Expression Characteristics Of Viviparous-1A In Triticum Spelta L

The isolation and characterization of Viviparous-1(Vp-1) haplotypes in Spelta wheat will further our understanding of the role of Vp-1in plant breeding designs. A total of8novel Vp-1haplotypes were identified in Spelta wheat which were designated as SVp1-Aa, SVp1-Ah and SVp1-Ai located in A genome, SVp1-Bc, SVp1-Bd and SVp1-Be in B genome, SVp1-Da and SVp1-Db in D genome. Compared with the Vp-1A, Vp-1B and Vp-ID orthologs, respectively, in bread wheat, sequence analysis showed that the SVp1-Aa, SVp1-Ah and SVp1-Ai had DNA similarities of87.61%,89.28and91.29%, respectively, with their ortholog from the A genome of bread wheat and demonstrated the existence of rich new allelic variation including several SNPs, five independent deletions of2bp (TA),2bp (TT),3bp (TAG),6bp (GAATTC) and33bp (11TTC repeats) deletions and many SNPs existed in A genome. By contrast, the SVpl-Bc, SVpl-Bd and SVp1-Be had DNA similarities of97.20%,99.16%and99.75%, respectively, with that of B genome ortholog in bread wheat with SVpl-Bc having an83bp deletion in the third intron which was the same as that detected in some bread wheat varieties and T. durum, SVpl-Bd having a25bp deletions in the third intron which was the same as that detected in a set of European wheat. The SVp1-Da and SVpl-Db showed98.06%and98.42%DNA similarity with their ortholog from the D genome of bread wheat with60bp insertion in the first intron, and SVpl-Db having a15bp deletion in the first exon.Semi-quantitative RT-PCR analysis showed that alternatively spliced transcripts of the Vp-IA and Vp-IB homologues were also present in these Spelta wheats, but Vp-1D, in which the correctly spliced transcripts were more highly expressed in some haplotypes than others; their expression level being closely related to their different responsiveness to ABA exposure. Therefore, we may conclude that both the mis-splicing of Vp-1transcripts and some indel variations detected in Spelta wheat and has been retained through the polyploidization and some haplotypes detected in these wheat related species might be valuable in breeding and selecting germplasm against wheat PHS problerm.