Burdock Associated Microbial The Burdock Growth And Quality Of The Research

Aims:To screen the strains which have effects on the growth and quality of Arctium lappa L. f rom rhizospheric microorganisms and endogenous bacteria, to analyze the effects and finally to identify these strains.Materials and methods:Burdock rhizospheric and non-rizhospheric fungi were isolated with spread plate method from burdock rhizoshperic soil of eleven provinces and sutonomoua regions of China. The rel ationship between fungal diversity and burdock quality was analyzed by SPSS statistical anal ysis software. Water culture experiments, germination testing and biocontrol experiments wer e applied to screen the strains which can inhibit the growth of burdock from 11 Fusarium sp. Different morphous characterizations;then the most toxic strain F130 and F131 identified by morphology and molecular biology methods. Endophytic bacteria were isolated from burdock root, stems, leaves, involucre and seeds in Baiqing in Shenyang with the surface disinfection method. HPLC was applied to detect the strains whose can transform arctiin to aglycon invitr o; the strain which has the highest transformation ratio was identified bypolyphasic taxonomy. Burdock rhizospheric fungi and endogenous bacteria colonizing capacity was studied by potte d experiments. with the microorganisms inoculated directly to burdock and field plant experi ments. were carried out in Baiqing, Shenyang and the capmpus of Dalian to study the effect of these strains to two years burdocks.Results and conclusion:1. We found that the number of rhizospheric Fusarium was 2.16 foldmore than n on-rzhix ospheric Fusarium and the ratio of rhizospheric Fusarium to the whole fungi was 13.40%, wh ile that of non-rhizospheric Fusarium was just 7.32% by comparing the rhizospheric and non-rzhixospheric fungi. The ratio of rhizospheric Trichoderma was lower, while that of Penicillium and Mucor have little changes. Shannon-wienerdi versity index(H) increased slightly; the uniformity of evenness index(J)decreased slightl y; indicating degree of dominance index(D)was basically unchanged.2. Hydroponic experiment found that six Fusarium strains of the 11 selected Fus arium strains were toxic to burdock seedlings; Fusarium F130 and F131 significantly i nhibited the germination rate and the length of radicle in germination experiment. The field plant experiments and aglycon content in burdock seedlings test found that Fusa rium F131 had significant negative impact to the accumulation of aglycon in burdock bud; Fusarium F131 can cause burdock seedlings sick after inoculated 48 d; at this ti me the amount of Fusarium was up to 5.8×104cfu/g. Biocontrol test found that 3 512A could colonize among burdock rzhixospheric and effectively inhitbited Fusarium F131, so that reduced morbidity. Morphological characterization and ITS molecular bio logical analysis identified F130 and F131 both as Fusarium solani.3.56 endophytic strains were isolated from burdock roots, stems, leaves, involucr e and seeds,Through HPLC quantitative determination of Arctiin and Aglycon content in vitro, using Arctiin powder as substrate,6 endogenous bacteria which had the ab ility of transforming Arctiin were screened out. Among these 6 strains, strain L2 had the highest conversion rate of, up to 76.9%. LC-MS verified the transformation produc t- Aglycon. L2 was identified as Microbacterium oxydans by morphological, physiologi cal and biochemical characteristics and 16SrDNA sequence analysis.4. Burdock endophytic bacteria G21 could significantly increase the grain weight o f Arctiin in the field plant experiments. Also, percentages of seed weight and the perc entage of grains of G21 test group, which significantly correlated with the grain weig ht, were higher than that of the control group. G21 was identified as Microbacterium by morphological, physiological and biochemical characteristics and 16SrDNA sequence analysis.