| Onion(Allium cepa L) belong to the lily family Allium,is one of the main cultivated vegetable in the world,also one of the main export vegetables in China.The main ingredient of onion is sulfide and sugar,with multiple effect,it can prevent many diseaes,food medicine, healtf care and oher fields think of it as important raw materials.The onion is strictly biennial plants,must be approved by vernalization and photoperiod induction to blossom.FT(FLOWERING LOCUS T) gene is a key gene in the regulation of photoperiodic reactions of plants to flower, also an important factor of blossom integration.It has been successfully cloned the onion flower similar genes AcFT1 and Ac LFT in our previous research work,in order to determine the function,we constructed justice,antisense and RNAi interference Ac FT1 and Ac LFT the plant expression vector,transformed into the Agrobacterium tumefaciens strain EHA105 by freeze thawing method, and then through the inflorescence infection method into the model plant Arabidopsis thaliana. Determination of Ac FT1 and Ac LFT expression in content in the leaves of Arabidopsis thaliana before bolting by fluorescence quantitative PCR method, to observe the morphological changes of transgenic plants,and then to determine the Ac FT1 and Ac LFT in onion flower in the role,to provide the reference for the implementation of the gene regulation of onion bolting blossom.The results are summarized as follows:(1)Constructed the plant expression vector p Z-Ac FT1 justice of Ac FT1,antisense plant expression vector p R-Ac FT1,RNAi plant expression vector p RNAi-Ac FT1;Constructed the plant expression vector p Z-Ac LFT justice of Ac LFT,antisense plant expression vector pR-Ac LFT,RNAi plant expression vector p RNAi-Ac LFT;(2)Using freeze-thaw method transfer recombinant plasmid p Z-AcFT1,p R-Ac FT1, p RNAi-Ac FT1,p Z-Ac LFT,p R-Ac LFT,p RNAi-Ac LFT into Agrobacterium EHA105,and Arabido psis was transformed by floral dip method.After resistance selection,Ac FT1 resistant seedlin gs were obtained 56 Ac LFT strains;74 strains for resistant seedlings.Extracted DNA of the resistant plants,identified by PCR,got 33 Ac FT1 positive strains,conversion efficiency of 59%;the Ac LFT positive strains of 50, the rate was 68%.(3)The relative expression of Ac FT1 and Ac LFT in Arabidopsis thaliana were determined by fluorescence quantitative PCR detection,The relative expression of Ac FT1 gene and Ac LFT gene were higher in transgenic Arabidopsis plants in justice;The relative expression of Ac FT1 gene were low in transgenic Arabidopsis plants in antisense;The relative expression of Ac FT1 gene were almost undetectable in transgenic Arabidopsis plants in RNAi;while The relative expression of Ac LFT gene were almost in transgenic Arabidopsis plants of antisense and RNAi compare with wild type Arabidopsis plants.(4)Analyzed the phenotype of transgenic plants, compared with wild type Arabidopsis,the transgenic Arabidopsis plants overexpressing Ac FT1 were early flowering:the contrast plants blossom after 29.7 days,the transgenic plants blossom 20.3 days,9 days in advance,but grow weakly,plant height of transgenic plants were decreased 27.4cm compare with the contrast,the number of rosette leaves were reduced by an average of 16 tablets,leaf area was reduced 2.3cm2,in addition, flower structure does not change,but the pods become smaller;Ac FT1 antisense expression in transgenic Arabidopsis plants were flowering delay,the average delay about 9 days, the plant growth vigor, as well as the decrease in the number of leaves,plant height decreased. Part of inflorescence flowers has not formed in the structure of the flower;transformation of Ac FT1 interference vector transgenic plant bolting out of inflorescence decreased significantly,only a small amount of flowers, and the flowering delay for more than 10 days, plant growth is weak, the number of rosette leaves was reduced by 14, the plant height of transgenic plants and the wild type and the other is the most short, shorter than wild type Arabidopsis 38.8cm.(5)Transformed Ac LFT justice, antisense and RNAi vector of Arabidopsis in the blossom time compared with the wild type is not much difference,but changes in morphological:morphological number crease in transformed justice plant,morphological number less ovbious in transformed antisense,RNAi plant; antisense,RNAi AcLFT plant plant height were shorter than the wild-type plants 27.7cm, 35.1cm and 37.2cm respectively, the number of rosette leaves than wild-type plants less 16,17,17 piece, an average reduction of leaf area 2.3 cm2,2.6 cm2,2.6cm2.(6)Genetically modified results show:Ac FT1 gene of onions is the flower gene,its expression can promote the plants blossom ahead of time,it will lead to plant flowering inhibition because of lack.The gene also influences the formation of inflorescence meristem,its expression is advantageous to inflorescence formation,and its expressssion can inhibit the formation of the inflorescence.Illustrate onion Ac LFT although similar in structure and expression of flowering gene,but it is not directly involved in the flower,its function is relevant of inflorescen happen. |
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