Study On The Regulation Of Tuber Development And Quality Formation Of Potato StBRI1

Brassinosteroids(BR)are the sixth major phytohormones that play an important role in the regulation of plant development and growth.BRI1(Brassinosteroids insensitive1)is the membrane receptor of BRs and plays a key role in BRs signal transduction.In the world,potatoes are the fourth largest food crop,also is a major vegetable cropand tubers are the main product organs.However,there are few studies on the effects of BRs and its key signal component StBRI1 on the growth and development of potatoes,especially the growth of tubers.In this study,the target gene was determined by analyzing the characteristics of the StBRI1 protein and its homology comparison.The StBRI1 gene was driven by the B33 tuber-specific promoter and the 35 S constitutive promoter to construct a plant expression vector and genetically transformed the potato to obtain the StBRI1 gene.The morphological indexes of aboveground parts,yield and quality of underground tubers of the two overexpression lines were determined to study the effects of StBRI1 overexpression on the growth and development of potato plants and tuber yield and quality influence.The results are as follows:1.The results of protein sequence homology comparison and phylogenetic tree showed that StBRI1 had the highest homology with Sl BRI1 in tomato.2.Expression of StBRI1 was highest in young tubers and roots,and lowest in stamens;However,StBRL1 and StBRL2 were expressed in the highest callus,and StBRL2 was almost not expressed in the stamens and petals.And the expression of the StBRI1 gene was higher than that of StBRL1 and StBRL2 in all of the tissues.3.Overexpression of StBRI1 resulted in up-regulation of relative expression levels of its homologous genes and tuber forming related genes.The relative expression of synthetic genes was down regulated.4.EBL treatment Désirée induced tube small tuber,which increased the yield of tuber,while BRZ inhibited the formation of tuber.Tuber-specific overexpression lines B33 and 35 S whole-plant overexpression lines both increased tuber yields under the conditions of inducing tubers.5.Compared with the wild type,the length of aboveground internodes and plant height of 35 S overexpression transgenic lines increased,but the number of stem nodes and stem diameter did not change significantly.There was no significant difference in the aboveground growth of B33 tuber specific overexpression lines compared with the wild type.6.The tuber yield of B33 tuber specific overexpression line and 35 S overexpression line pot experiment were higher than that of wild type,which was mainly reflected in the increase of tuber block quantity.In terms of tuber quality,soluble sugar,soluble protein and ascorbic acid increased.