Isolation Of TaABI5 And Development Of A STS Marker For Pre-harvest Sprouting Resistance In Chinese Bread Wheat

Dormancy is a major factor affecting the pre-harvest sprouting(PHS)resistance of wheat.ABI5 and ABI3 as intermediates in ABA signaling regulate the seed maturation and germination,and expression of genes facilitate desiccation tolerance as embryos dehydrate in later maturational stages.In this study,the full length sequence of TaABI5 was amplified from the cultivar Zhou 8425B,total 16 multiple copies of ABI5 sequence were obtained,which were named as TaABI5-AL TaABI5-A2,TaABI5-A3,TaABI5-Bl,TaABI5-B2,TaABI5-B3,TaABI5-B4,TaABI5-B5,TaABI5-D1,TaABI5-D2,TaABI5-D3,TaABI5-D4,TaABl5-D5,TaABI5-D6,TaABI5-D7 and TaABI5-D8,respectively.Three gene specific primers,TaABI5D3F/R,TaABI5D7F/R and TaABI5D6F/R were established to amplify specificity the sequences of TaABI5-D3,TaABI5-D6 and TaABI5-D7,respectively.In addition,two allelic variants of TaABI5-D7 were identified on chromosome 3D in common wheat,designated as TaABI5-D71 and TaABI5-D72,respectively.Based on the two different SNPs sites existed in sequences of TaABI5-D71 and TaABI5-D72,two dominant complementary markers were developed,designated as TaABI5D7a and TaABI5D7b,which could be used as an efficient and reliable marker to evaluate the depth dormancy of wheat seeds.Using the marker TaABI5D7a,a 494-bp PCR fragment was amplified from the PHS resistant cultivars,no PCR product was detected in susceptible ones;whereas,a 703-bp fragment was from the susceptible ones,no PCR product was detected in resistant ones,using the marker TaABI5D7b.Of the Chinese bread wheat cultivars,103 were used to validate the relationship between the polymorphic fragments of TaABI5-D7 and PHS tolerance.Statistical analysis indicated that TaABI5D7a and TaABI5D7b were significantly(P<0.01)associated with the germination index(GI)values in these germplasms.To further confirm the association between allelic variants of TaABI5-D7 and PHS tolerance,200 recombinant inbred lines(RILs)from the cross between Zhongyou9507(TaABI5-D72)and Yangxiaomai(TaABI5-D71)were genotyped using the marker TaABI5D7a and TaABI5D7b.General linear model analysis indicated that variation in TaABI5-D7 had a significant(P<0.01)association with the germination index(GI)values,explaining 42.3%,60.8%and 63.7%of the phenotypic variation in GI in Shijiazhuang,Beijing and the averaged data from those environments,respectively.