Cloning And Evolution Analysis Of ASY1in Brassica

ASY1is an associated protein for synaptonemal complex formation during meiosis in Arabidopsis thaliana and play a key role in homologous chromosome identification and pairing. In this study, we cloned and sequenced ASY1genes from three allotetraploids Brassica. napus (AACC), B. juncea (AABB), B. carinata (BBCC) and three diploids B. rapa (AA), B. oleracea (CC) and B. nigra (BB) to reveal the genetic variation during the evolution of Brassica polyploids and underlying contribution of these variations to adaption of polyploid meiosis. Main results of this study are described as follows:(1)25CDS of ASY1were obtained from9B. napus,5B. juncea,3B. Carinata,4B. rapa,3B. oleracea and1B. nigra separately by RT-PCR or PCR cloning.(2) Genomic specific variations were found in the CDS of ASY1from A, B and C genomes.(3) Some common and specific variations were found between Arabidopsis thaliana, Arabidopsis Lyrata, Thellungiella salsuginea and three Brassica diploids, which may be the key variations for adaption of genome triplication of Brassica.(4) By sequence alignment among CDS of ASY1in the same genome from Brassica diploids and allotetrapolyploids, it was found that there are also some specific variations in B and C genome between tetraploids (B. juncea, B. carinata) and according diploids (B. nigra, B. oleracea). These variations may be important for adaption of another run of genome polyploidization of Brassica.(5) It was found that although the meiosis of B. juncea and B. carinata are similar and regular in different varieties, major difference was found between different varieties of B. napus. However, no any specific sequence variation of ASY1was found related to this type of meiosis divergence.