| Eggplant(Solanum melongena L.) is Solanaceae Solanum crops, and it is the important vegetable that is widely cultivated in China. The nutrition value of eggplant contains many vitamins and minerals. Eggplant has the health function, and can be useful for asthma, bronchitis, cholera and cardio vascular disease. But eggplant is susceptible to BW(bacterial wilt) that caused by Ralstonia solanacearum, and which belongs to the soil borne disease, it is widely distributed, breeding rapidly, and difficult to prevention by conventional methods, especially in South China, 20%~30% off, even 60% off products can be caused by BW. The breeding resistance of eggplant is important to overcome the problem and greatly improve the yield and quality of eggplant. But up to now, reports of molecular mechanism on regulating BW resistance in eggplant is still few. Therefore,separation and identification of genes relevant to controlling BW resistance is significant for eggplant disease resistant breeding.A NAC transcription factor was cloned by the RNA-Seqing methods, named SmNAC(Gen Accession: KM435267), that express significant differentially in a resistant(E-31)and susceptible(E-32) eggplant line, the function and expesstion characterization of the gene were detected in the study. The results were showed as following:Sequence analysis showed that SmNAC was 1,708 bp long with an ORF of 1,038 bp.The SmNAC protein was predicted to have 345 amino acids, a molecular weight of 39035 k Da and an isoelectric point of 8.94, and contained a conserved domain of NAC transcription factor. Subcellular localization prediction showed SmNAC localized in nucleus, and transient expression in S. melongena(E-32) protoplasts also validated that SmNAC localized in nucleus.The results of qPCR showed that SmNAC could be detected in roots, stems and leaves,but with the highest expression in stems and the lowest expression in leaves. Prior to inoculation, the expression level of SmNAC was higher in susceptible(E-32) than that inresistant(E-31) plants. After inoculation with R. solanacearum strains, SmNAC transcript levels increased in susceptible S. melongena(E-32), but decreased in resistant S.melongena(E-31). However, the expression was substantially greater in E-32 plants. These results suggested that SmNAC can be induced by BW pathogens. At the same time, E-32 plants were treated with Me JA and JA, the results indicated that Me JA could induce the expression of SmNAC, but SA not.Histochemistry immunity in situ detection showed that SmNAC proteins are mainly distributed in the root and stem of eggplant, and pathogen can induce the accumulation of the protein.Functional identification by VIGS silenced SmNAC gene in susceptible eggplants material showed that silenced VIGS plants exerted stronger BW-resistance rather than control plants after inoculation of R. solanacearum. The results suggested that it can enhance the BW-resistance of susceptlbe plants by silencing SmNAC gene, in addition,SmNAC gene played a negative role in regulating BW resistance in eggplants.The SmNAC over-expressing vectors of SmNAC was constructed, and p BI-SmNAC was transformed into the ‘E-31' eggplants by Agrobacterium Tumefaciens-mediated method. Six SmNAC over-expression transgenic plants(named as EGT0-5?EGT0-23?EGT0-43?EGT0-87?EGT0-145 and EGT0-204) were obtained. These were used to assess BW resistance.The resistance of the transgenic SmNAC overexpressing plants were lower than that the non-transgenic plants(E-31). We concluded that overexpression of SmNAC in S.melongena reduced resistance to BW in the eggplant.After silencing SmNAC gene, We measured the expression of the signal genes(EDS1?SGT1?Glu A?PAD4?NPR1?TGA?PR-1a) in VIGS plants by qRT-PCR, the expression level of the signal genes are higher than that in the non-tansgenic plant(E-32). But the expression levels of these signal genes in the overexpression transgenic plant were significantly lower than that in the non-transgenic plant(E-31). So SmNAC affects the expression of signal gene in SA pathway. |
PDF Full Text Request