Cloning And Functional Analysis Of BcJAZ3 Gene From Chinese Flowering Cabbage(Brassica Parachinensis L.H.Bailey)

Chinese flowering cabbage is a kind of vegetable with flower stem in the Brassica,which originated in the south of China and is one of the main cultivated vegetables in South China.Its planting area accounts for 35% to 40% of the total planting area of vegetables.It is cultivated all year round and can be produced on an annual basis,so it plays an important role in the supply of vegetables in the off-season.Anthracnose is the main Pathogenic bacteria of a variety of food,vegetables and fruits,which is one of the main diseases in the growth and development of Chinese flowering cabbage.The high temperature and high humidity climate is conducive to the reproduction and spread of the Pathogenic bacteria in South China.This results in a yield loss of 30% to 40%.The main pathogen causing infection of anthracnose in cruciferous vegetable crops is Colletotrichum higginsianum,and the molecular mechanism of resistance to anthracnose is not fully understood.In the previous study of the research group,the transcriptome study on the infection of the Chinese flowering cabbage in response to anthrax pathogens.In this study,the differentially expressed genes of disease-resistance and susceptible-disease were screened from the previous study,mainly to investigate The specific mechanism of JA signaling regulator Bc JAZ3 in inducing disease resistance of Chinese flowering cabbage.The main findings are as follows:(1)According to the sequence of Bc JAZ3 gene obtained by transcriptome sequencing,the full-length CDS sequence of Bc JAZ3 gene was obtained by homologous cloning from the leaves of Chinese flowering cabbage: the full length of the sequence was 1071 bp,including a complete open reading frame,encoding a total of 356 amino acids.The informatics analysis showed that the secondary structure of the protein encoded by Bc JAZ3 was mainly composed of irregular bending.There were 51 α helices in the secondary structure,accounting for 14.89%,37 extension chains accounting for 10.96%,and 10 βfolding,accounting for 2.81.%,254 irregular curves,accounting for 71.35%.The amino acid encoded by this gene contains two conserved domains unique to JAZ3: the TIFY conserved domain and the CCT＿2 conserved domain.Belongs to the JAZ3 family.Tertiary structure predictions indicate that the amino acid sequence consists of one strand and is predicted to be a transcriptional regulator.In addition,subcellular localization revealed that Bc JAZ3 is localized to the nucleus and is a nucleus protein.(2)Disease resistence could be differentiated by spraying inoculation with Colletotrichum higginsianum,Verification and identification of susceptible varieties(Youlv701)and resistant varieties(Chixin NO.2)and Youlv 701 disease index was 61.48%belonging to susceptible varieties,and the Chixin NO.2 disease index was 52.82%belonging to the medium resistant variety,and from the time of inoculation,samples were taken at 0/6/12/24/48 hours,Bc JAZ3 was verified by real-time fluorescence quantification(q RT-PCR)to study the change of Bc JAZ3 gene expression level with time after inoculation.(3)The Bc JAZ3 vector was constructed by VIGS silencing technology,and then transferred into Agrobacterium to infect Chinese flowering cabbage.After 7 days later,the expression of Bc JAZ3 gene was analyzed in the infected plants and the control plants.The experimental results showed that the expression level of Bc JAZ3 gene in the infected plants was lower than that of the control plants.In summary,the Bc JAZ3 gene is involved in the regulation of anthracnose,and the results further enrich the molecular research on the disease resistance of anthracnose,and provide new feasibility for the production of technical measures to prevent and control acacia.The program and theoretical basis also provide new ideas for the genetic improvement of Brassica campestris.