The Cloning And Functional Analysis Of Three Taproot Development-related Genes Of Sugar Beet (Beta Vulgaris L.)

Sugar beet(Beta vulgaris L.)whose economy organ is taproot is a sugar-yielding crops.Taproot weight and sucrose content are the important economic trait.Thereby,it is the important theoretical basis for improving the yield and quality of sugar beet that revealing molecular mechanism of taproot growth and sucrose accumulation.Therefore,in this study,cloning the genes(Bv_fefj and Bv_wnjc)of ethylene-responsive element binding factors(ERF)and BvCPD which code the rate-limiting enzyme of brassinosteroids.These molecular funcation involving in regulating the taproot development were studied in transgenic Arabidopsis.These works will lay the foundation of molechular mechanism involved in ethylene and brassinosteroids regulating the sugar beet taproot development.Main results are as follows:1.The sequence of AP2/ERF conserved domain was used as baits to search in sugar beet(Beta vulgaris L.)genome.According to phylogenetic analysis,conservative motif analysis and the expression pattern profiling of BvERF,68 BvERFs were identified,and classified into 10 groups.Transcriptomic profiling suggest that a total of 15 memebers of BvERF family were involved in taproot turning to rapid,such as Bv_ammr,Bv_fefj and Bv_wnjc.Among them,Bv_ammr may be related to the high yield characteristic of sugar beet.Bv_ignp,Bv_sqfr and Bv_khde were realted to that the taproot of high taproot yield cultivar growed more rapidly than the taproot of high sucrose content cultivar.Bv_wnjc may be negatively relevanted to the growth rate of taproot.Bv_fefj may be involved in taproot with more vascular ring in high sucrose content line.2,The CDS length of BvCPD,Bv_fefj and Bv_wnjc are respectively 1422 bp,708bp and 804 bp.The CDS of BvCPD and Bv_wnjc are unanimous to the reference in sugar beet genome.The CDS of Bv_wnjc is six more than the reference in sugar beet genome.3,The transgenic line of BvCPD have higher brassinolide content than wild Arabidopsis.The overexpression of BvCPD promoted the expression of TCH4 and BGLU29,thereby promoting the root cell growth and root growth.In the root of Arabidopsis,cell division was accelerated when Bv_fefj is overexpresed.Overexpression of Bv_fefj changed the growth strategy of root by promoting the cell division and suppressing the cell expansion,which result that the root length of transgenic lines are shorter than the wild line.This result may be concerned with the up-regulated expression of CYCD3;1 and down-regulated expression of BGLU29 which are regulated by Bv_fefj transcription factor.In the transgene lines with shorter root in which Bv_wnjc was overexpressed,cell-expansion was suppressed.