Screening And Mechanism Of The Strains Promoting Growth And Accumulation Of Chlorogenic Acid Of Chrysanthemum Morifolium Cv.BoJu

In this study,the C.morifolium cv.BoJu was used as experimental material,and the endophytic bacteria of the C.morifolium cv.BoJu and the non-endophytic strains in the laboratory were used for symbiotic culture with the tissue culture seedlings.The physiological and biochemical tests,active substance determination tests,transcriptomes and other means were screened out.The strains that promote the growth of C.morifolium cv.BoJu and the accumulation of active substances,and the molecular mechanism of the accumulation of active substances,will lay an important foundation for the future development and application of agriculture.The main contents and results of this study are as follows:1.Establishment of tissue culture system of C.morifolium cv.BoJu: Tissue culture with stem segment,stem tip and leaf as explants showed that the survival rate of stem tip was the best.Finally,the suitable medium for callus induction was selected as 1/2 MS + agar 8.5 g/L + sucrose 30.0 g/L,pH 5.8,and the medium suitable for rooting and proliferation was MS + agar 8.5 g/L + sucrose 30.0 g/L,pH 5.8.2.Primary screening of functional strains: 14 strains isolated from the previous stage were inoculated with chrysanthemum tissue culture seedlings.After 15 days of symbiotic culture,the growth indexes,growth,plant height,root length and root number of chrysanthemum tissue culture seedlings were observed.The physiological indexes such as chlorophyll content,soluble sugar content and root activity of the tissue culture seedlings were preliminarily selected to promote the growth promoting bacteria BJF10 and BN7.3.Re-screening of the strains: After 15 days of symbiotic culture with endophytes,the tissue culture seedlings of Chrysanthemum morifolium were transplanted to greenhouse one week later.After one month,the physiological indexes of Chrysanthemum morifolium in the inoculated group and the non-inoculated control group were determined,including chlorophyll content in leaves,MDA(malondialdehyde)content,root activity,soluble sugar content and PAL(phenylalanine ammonia lyase)activity.The results showed that the leaves inoculated with BJF10 showed significant difference compared with the control;the content of MDA decreased in the leaves of C.morifolium cv.BoJu inoculated with BN7 compared with the control;BJF10 and BN7 were found to increase the degree of C.morifolium cv.BoJu root activity,soluble sugar content,PAL enzyme activity.4.Effect of growth-promoting bacteria on chlorogenic acid content in leaves of C.morifolium cv.BoJu:HPLC method for determination of chlorogenic acid contentwas established by optimizing sample processing,mobile phase and detection wave length.The content of chlorogenic acid in leaves treated with endophytic bacteria BJF10 and BN7 was determined.It was found that endophytic bacteria BJF10 and BN7 can increase the content of chlorogenic acid in leaves,and BJF10 was twice as high as that in non-inoculated control group,indicating that endophytic bacteria BJF10 and BN7 could significantly increase quality.5.Transcriptome analysis: The transcriptome sequencing of the endophytic treatment group and the control group was carried out,and the differential expression profiles of the genes related to the metabolism of active substances were analyzed to reveal the gene expression of the strains on the leaves of the genus Chrysanthemum at the molecular level.The effect of the level.In summary,the strains BJF10 and BN7 were screened to promote the growth of geranium and the accumulation of chlorogenic acid,which laid a foundation for the future development of agricultural microbial composites.