Research On Bolting And Flowering Related Molecular Mechanism Of Sugar Beet Induced By Temperature And Light

Bolting and flowering of biennial beet were induced by vernalization and long light.Insufficient vernalization and light will delay bolting and flowering,leading to miss the optimal season,decreased yield,and influence breeding processes.There was early bolting phenomenon that reduced the weight of beet root,sugar content and the amount of recycled sugar in the raw material production.So the studies of molecular mechanism associated with bolting and flowering inducing by vernalization and light were important in academic and application.Differences of genes expression pattern and proteomics were investigated by AFLP and i TRAQ technologys respectively.In the meanwhile,physiological and biochemical factors and data analysis of bioinformatics in leaves of sugar beet under different conditions were also performed in order to illuminate the molecular mechanisms of genes,proteins,physiological and biochemical factors associated with vernalization,light,bolting and flowering at different developmental stages.Firstly,266 genes were isolated by the c DNA-AFLP technology,among which 58 genes were associated with vernalization,21 genes were associated with light,40 genes were associated with bolting,and 30 genes were related to flowering.Phenylpropanoid biosynthesis pathway and circadian rhythm pathway were associated with bolting of sugar beet.Sphingosine biosynthesis and sphingolipid metabolism pathways were associated with flowering of sugar beet.Secondly,1435 proteins in leaves from different developmental stages under different conditions were identified by i TRAQ technology.Phenylpropanoid biosynthesis,diterpene biosynthesis,plant hormone signal transduction and protein processing in endoplasmic reticulum pathways were associated with vernalization.Photosynthesis,glyoxylate and dicarboxylic acid metabolism,glutathione metabolism and m RNA survey pathways were associated with photoperiods.Abnormal m RNAs were enriched by the dormancy of m RNA monitoring pathway which was due to short light,inhibiting the reproductive transformation of sugar beet.PAB4、ERF1-1 and SR45 in mRNA monitoring pathway were very important to the normal growth of sugar beet.Bolting was synergistically promoted by chromatin structure and kinetic proteins associated with vernalization and photoperiods.The proteins with antioxidant activity and enzyme activity regulators were unique to the growth stage of flowering,promoting flowering of sugar beet.Thirdly,GSH content probably related with the transformation from vegetative to reproductive growth.Furthermore,glutathione metabolism potentially participated in and regulated flowering process of sugar beet.Analysis of IAA concentration revealed that IAA probably induced bolting and flowering in a threshold manner that if the threshold was greater than the value,it will not i nduce bolting,otherwise it will not induce flowering.ABA played an important role in the adaptation to the photoperiods.Although the content of endogenous ABA was higher than IAA in leaves,IAA may be more powerful to reproductive development than ABA.Finally,data analysis of bioinformatics showed that Bv AGL15X2 was a long non-coding RNA(Lnc RNA)and Bv RAV1-like was a vernalization gene of sugar beet.Bolting was induced by the synergistical expressions of BvRAV1-like,Bv RVR4,Bv Os07g0563300X1,Bv Os07g0563300X5 and Bv FT2 genes.Flowering was induced by the synergistical expressions of Bv RAV1-like,BvBBX19,BvRVR4 and Bv FT2 genes,among which BvFT2 played a key role in the reproductive growth of sugar beet.