Functional Analysis Of BREVIPEDICELLUS Gene That Involved In The Regulation Of Plant Architecture In Brassica Napus L.

Brassica napus L.is one of the world’s main edible oil crops and a significant source of biofuel.Low yield per unit area and low rate of mechanized production are important factors restricting the expansion of the rapeseed industry in China.Improving the canopy structure of rapeseed to respond to intensive planting circumstances and identifying rapeseed cultivars appropriate for mechanical harvesting are the keys to enhancing rapeseed yield and promoting mechanized harvesting.Branch angle is an important component factor of rape plant architecture,which determines the compactness of the rape canopy structure.The moderate compact plant structure of rape can reduce the shading between branches and recover the utilization rate of population light energy,and moderately refine the sowing density.Conversely,it can also reduce the entanglement between branches of plants during mechanized harvesting and the consequent cracking and shedding of siliques,which is beneficial to mechanized harvesting.Therefore,optimizing the branching angle of rape is of great significance in improving rape yield,and mechanized harvesting.BREVIPEDICELLUS(BP/KNAT1)is a member of the Class I KNOTTED-like homeobox gene family,which is a vital transcription factor in plants and has a significant regulatory effect on plant growth and development.In this project,based on the BP gene,the purpose is to explore the regulatory effect of the gene on the plant architecture in Brassica napus L.Firstly,the BP homologous gene was cloned by molecular biology method in Brassica napus L.,named BnaBPA03 and BnaBPC03.The sequences of the two genes are almost identical,with a similarity of 98.54%,and the sequence of BnaBPA03 is more similar to the sequence of the BP gene in Arabidopsis,so BnaBPA03 was selected for further studies.q RT-PCR was implemented to detect the expression of BnaBP in various tissues of rapeseed and found that the expression of BnaBP in the roots,stems,and pedicels was high,indicating that the BnaBP are likely to exert its function in these parts.Bioinformatics analysis showed that BnaBPA03 was localized in the nucleus as a relatively unstable hydrophilic protein with a high degree of phosphorylation.By subcellular localization analysis,the BnaBPA03 protein was observed to be localized in the nucleus.An overexpression vector and CRISPR/Cas9 gene-editing vector were constructed,the overexpression and gene editing lines were obtained.The agronomic traits such as plant height and branching angle of the obtained plants were measured.The plant height of overexpressed BnaBPA03 rapeseed was higher than that of the wild type,while the branching angles of the BnaBP overexpressed plants were found smaller than those of the wild type.Additionally,the roots of gene-edited mutant strains showed shorter and obvious developmental defects.In contrast,overexpressed mutants displayed relatively long roots,changed leaf morphology and flowering time.Overall,our results show that regulating BnaBP may improve plant architecture and change flowering time in Brassica napus L.In summary,the homologous gene of BP was cloned in Brassica napus L.,and based on the similarity of the sequence,BnaBPA03 was identified as the key research object.Through the analysis of BnaBP tissue-specific expression patterns,subcellular localization analysis,overexpression,and phenotype analysis of gene-edited transformed strains,the regulatory effect of this gene on the plant height,branching angle,leaf morphology and other plant architecture was preliminarily revealed in Brassica napus L.,which provided new ideas for rapeseed molecular breeding and a reference basis for cultivating rapeseed varieties conducive to mechanized harvesting.