Isolation And Characterization Of ABI5 In Chinese Wheats With Different Depth Of Dormancy

Dormancy is a major factor affecting the pre-harvest sprouting (PHS) resistance of wheat. ABI5 can regulate the sensitivity of embryo to ABA, and play an important role in the establishment of the mechanism of desiccation tolerance and the embryo dormancy. In this study, the whole length of the ABI5 gene was amplified and sequenced in Chinese wheat with different depth of dormancy by using universal primers. In addition, approximately 6 copys of ABI5 gene sequences were predicted in this study by comparing the homology and similarity of the sequences. And then two pairs of specific primers were designed and screened out. Moreover, two copys of ABI5 sequences, ABI5-1 and ABI5-2 were identified respectively. Compared with ABI5 of Alto spelt wheat and Aegilops tauschii, ABI5-1 and ABI5-2 have the higher homogolous with ABI5 of Triticum Urartu. In addition, the patten of transcript expression of ABI5 was characterized in Chinese wheat with different depth of level, the result showed that the transcript expression level of ABI5 gene was related to the degree of seed maturity. The more degree of seed maturity, the more transcript expression level. And there was the most expression level of ABI5 in seeds at 30d after flowering. Different transcript expression level of ABI5 gene was observed in wheat with different depth of level. the expression amount of weak dormancy wheat materials was less than the strong dormancy wheat materials Langzhongbaimaizi and Wanxianbaimaizi with strong depth of level, had more transcript expression level of ABI5 then Zhongyou 9507 and Jing 411 with weak depth of level. As with above pattern of transcript expression ABI5 in different development stage and different cultivars, the transcript expression level of ABI5-1 and ABI5-2 were characterized, and similarity result was observed in different development stage and different cultivars.By electron microscope scanning, endosperm starch granules of Zhongyou 9507 and Jing 411 were more tightly wrapped by matrix protein than Langzhongbaimaizi and Wanxianbaimaizi, which were loosely bound with matrix protein and exposed mostly. Moreover, in the process of seed germination, the breakdown speed and degree of endosperm starch granule in Langzhongbaimaizi and Wanxianbaimaizi were bigger than in Zhongyou 9507 and Jing 411.There was not only the pre-harvest sprouting resistance in the harvest season but also drought resistance in the wheat sowing season and early growth stage was damaged in major planting provinces of spring wheat in our country. In this study, five molecular markers were selected to identify drought tolerance and PHS tolerance in 137 germplasms from Inner Mongolia, including three molecular markers were STS markers Vp1B3, Vp1A3 and TamyblOD associated with PHS tolerance and two dominant complementary markers TaNRX-Blal and TaNRX-B1b1, and co-dominant STS markers FerAl-intrl which were all associated with drought resistance in wheat. The results showed that Chinese spring was the haplotype of TaVp-IBb and has PHS resistence fragment amplified with TamyblOD; Liaochun 10 was PHS resistence haplotypes in all three molecular markers associated with PHS tolerance. Total 58 cultivars (the frequency was 42.34%) like as 73B609 was the haplotypes combinations TaNRX-Blal/TaFer-Ala could be used as potential parents for drought resistance,and could used as parents materials for the breeding of drought resistance.In addition, Liaochun 10 was drought resistance haplotypes in two molecular markers associated with drought resistance, so Liaochun 10 could be potential parents in the breeding of drought resistance and PHS resistance.