Isolation And Characterization Of The NF-YB Transcription Factor Family In Canola (Brassica Napus L.) And The Promoter Analysis And Genetic Transformation Of BnNF-YB2/3/4/5/6

NF-Y (NUCLEAR FACTOR-Y), a heterotrimeric transcription factor, is composed of NF-YA, NF-YB, and NF-YC subunits. NF-YA, NF-YB, and NF-YC are present as only one copy, respectively, in fungi (for example, yeast) and animals systems. While in plants, each of them forms a multimember family. NF-Ys are key regulators with important roles in many physiological processes, such as drought tolerance, flowering time, and seed development. Canola, an important oil crop, can be used as industrial raw materials, biodiesel, and animal feed. And various transcription factors may involve in canola growth and development to respond to diverse signals in vitro and in vivo.In this study, Brassica napus NF-YBs were isolated by homology cloning method; the conserved domains, evolutionary relationships, identities and gene structures of them were constructed and analysed by bioinformatics methods; the relative expression levels of them in diverse tissues at different development stages or under different stresses, such as salt, drought, and ABA; the promoters of BnNF-YB2/3/4/5/6 were also cloning, charaterized, and analysed by bioinformatics methods; the 35S::BnNF-YB2/3/4/5/6 were constructed and were introduced into Arabidopsis thaliana Col-0 (WT, nf-yb2, and nf-yb3) and rapeseed (’Nanyanyou 1’and’Zhongshuang 11’). The major results are as follows:1.14 NF-YBs isolated and characterized from ’Nanyanyou 1’were named as BnNF-YB1, BnNF-YB2,..., and BnNF-YB14 referring to the NF-YB in Arabidopsis thaliana, Brachypodium distachyon, and poplar.2. The analysis of evolutionary relationships, identities and gene structures indicated that BnNF-YB1 and AtNF-YB1 were highly homologous as well as BnNF-YB2/3 and AtNF-YB2, BnNF-YB4/5/6 and AtNF-YB3, BnNF-YB7 and AtNF-YB5, BnNF-YB8/9 and AtNF-YB6, BnNF-YB10/11 and AtNF-YB7, BnNF-YB12 and AtNF-YB8, BnNF-YB13 and AtNF-YB9, and BnNF-YB14 and AtNF-YB10.3. The analysis of the conserved domain of BnF-YB proteins revealed that BnNF-YB were composed of three regions-the A region in the N terminal, the B region in the middle, and the C region in the C terminal. The A and C regions were non-conservative, while the B region was the conserved domains of BnNF-YBs. The B region, similar to H2B histone fold motif (HFM) and composed of αl,α2, α3, and αC; was responsible for interacting with NF-YA and NF-YC and binding to the CCAAT box.4. The analysis of the relative expression levels of BnNF-YBs showed their expression patterns were almost not similar during development or under diverse stresses and that the expressions of each BnNF-YB in different tissues under the same conditon either kept not stable, which suggested that each of BnNF-YB may play various roles during canola development or under diverse stresses.5. The analysis of BnNF-YB2/3/4/5/6 promoters showed that they shared the various cis-acting elemets in responding to light, salt, and ABA as well as cell cycle. It could be indicated that BnNF-YB2/3/4/5/6 might respond to diverse signals in vitro and in vivo, thereby regulating the canola growth and development.6. The 35S::BnNF-YB2/3/4/5/6 were constructed and were introduced into Arabidopsis thaliana Col-0 (WT, nf-yb2, and nf-yb3) and rapeseed (’Nanyanyou 1’and ’Zhongshuang 11’) by floral-dipping method. The transgenic seedlings of many of them were gotten.