Cloning And Sequence Analysis Of Fragments Related To Low Temperature Requirement Late Bolting In Chinese Cabbage

Chinese cabbage (Brassica campestris L.ssp. pekinensis) is one of the biennialvegetable crops, and needs a prolonged period of low temperature (vernalization) to induce flowering. In spring cultivation of Chinese cabbage, the low temperature and the longer day-length causes premature bolting andgreat loss in product. To breed late bolting variety is an effective way to solve the problem.Towards exploring the molecular base of late bolting in Chinese cabbage, a DH population including 81 lines derived from the cross between early bolting Chinese cabbage " BY" and extremely late bolting turnip "M.M" was used in this study. Six extremely early bolting lines and six extremely late bolting lines were chosen from 81 DH lines to construct early and late bolting bulk, respectively. cDNA-AFLP analysis was carried out in two bulks and two parents with or without low temperature treatments under 3-5 °C for 25 days by 256 pairs of AFLP primer combinations. Three differentially expressed cDNA-AFLP fragments were cloned and sequenced. Sequence and BLAST analysis indicates that P65m47cDNA fragment has 80% identity with C2 domain-containing protein gene with the expect ratio of 7e^-17, which plays an important role in signal transduction; p66m55 I cDNA fragment has 85% identity with Arabidopsis thaliana unknown protein AT1G32530 cDNA with the expect ratio of 5e^-36, which encodes protein binding / ubiquitin-protein ligase / zinc ion binding; p66m55cDNA II fragment has 87% identity with A. thaliana AT1G65590 cDNA with the expect ratio of 4e^-37, which encodes beta- N- acetylhexosaminidase. These three fragments express bothtwo bulks and two parents without low temperature, but don' t express in early bolting bulk and early bolting parent, their expressing profile and function shoold be further study.