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Screening Of Ginseng Endophytes With Antagonistic Growth Promoting Ability And Their Effects On Adventitious Roots Of Ginseng

Posted on:2024-05-25Degree:MasterType:Thesis
Country:ChinaCandidate:Z YinFull Text:PDF
GTID:2543307121496204Subject:Biology and Medicine
Abstract/Summary:PDF Full Text Request
Panax ginseng C.A.Meyer is a perennial herbaceous plant of the Panax genus in the Araliaceae family.It has a long medicinal history due to its high medicinal value.Ginseng endophytes,as symbiotic microorganisms with ginseng,are often closely related to the growth and development of ginseng and to the stress of adversity,and are a class of microbial resources of great value for exploitation.In this study,endophytic ginseng bacteria were isolated and purified from six healthy four-year-old ginseng roots,from which endophytic bacteria with antagonistic ability against common ginseng pathogens were selected and their growth-promoting and saponin-producing abilities were determined.The endophytes were identified by morphological and molecular biological methods,and their biological properties were also investigated.Finally,they were co-cultured with ginseng adventitious roots to investigate the biomass accumulation,physiological and biochemical parameters and saponin content of ginseng adventitious roots under co-culture conditions.The results are as follows:1.Seventy-two endophytic ginseng strains,including 59 endophytic bacteria and 13 endophytic fungi,were isolated from six ginseng samples using the tissue milling method.2.Six endophytic strains with the ability to antagonize more than two common ginseng pathogens were obtained by plate confrontation and growth rate screening.Among them,strain PDA-16 had the broadest spectrum of inhibition and was able to antagonize the growth of six ginseng pathogens to different degrees.3.The results of the determination of the growth-promoting capacity of the antagonistic ginseng endophytes showed that all six endophytic strains had some nitrogen fixation capacity,NA-25 had a strong IAA production capacity,PDA-16 had a strong phosphorus solubilisation capacity and NA-27 had a strong iron carrier production capacity.4.The antagonistic ginseng endophytes were cultured in liquid form and the products were extracted using the ODS method.The HPLC method was used to determine that the culture of strain NA-25 contained protopanaxatriol PPT and ginsenoside Rh2 at 0.53 mg/L and 0.035 mg/L,respectively,and that the culture of strain NA-27 contained mesopanaxatriol PPT at 0.28 mg/L.5.The results of morphological and molecular biological identification of the antagonistic ginseng endophytes showed that strain NA-5、NA-9、NA-27、NA-31 were bacteria of the Variovorax sp.,strain NA-25 was bacteria of the Agrobacterium sp.,strain PDA-16 was bacteria of the Hyphomicrobium sp.6.Biological characterisation showed that the nutritional requirements of strain NA-25 were:soluble starch 5 g/L,peptone 10 g/L,calcium chloride 5 g/L,p H 7.0,optimum incubation temperature 30℃.Nutritional requirements of strain NA-27 are: maltose 5 g/L,peptone 10 g/L,magnesium chloride 5 g/L,p H 8.0,optimum incubation temperature 28℃.Nutrient requirements for strain PDA-16 are: methanol 15 m L/L,ammonium nitrate 5 g/L,sodium chloride 5 g/L,p H7.0,optimum incubation temperature 28℃.7.The strains NA-25,NA-27 and PDA-16 can promote the growth,ginsenoside synthesis and antioxidant capacity of adventitious roots of ginseng to varying degrees,effectively alleviating the effects of pathogenic bacteria on the biomass accumulation and saponin content of adventitious roots,and improving the tolerance of adventitious roots of ginseng to pathogenic bacteria.
Keywords/Search Tags:Ginseng, Endophyte, Antagonism, Growth promotion, Ginseng adventitious root
PDF Full Text Request
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