Effects Of Penicillium And Trichoderma On Root Rot Disease Of Ginseng Caused By Fusarium Oxys Porum

Ginseng is a traditional Chinese herb with multiple effects,such as invigorating qi,invigorating spleen and lung,calming the nerves and increasing intelligence.Ginseng cultivation production in China accounts for about 70%of the world,and the production area is mainly in Jilin Province in the northeast,with provincial production accounting for about 85%of the total national production.Research shows that the yield loss of ginseng caused by soil-borne diseases is up to 30%-60%,or even threatened with extinction,which has become a bottleneck restricting the development of ginseng industry in China.Ginseng root rot caused by Fusarium oxysporum significantly reduces the yield and quality of ginseng roots,and biological control is a safe,environmentally friendly and sustainable control method.Currently,for biological control of plant diseases,there is a preference for the combined application of several strains,with the aim of enhancing or synergizing disease control effect.Penicillium and Trichoderma are wide spread in the rhizosphere soil of plants.Some Penicillium and Trichoderma strains have been shown to control specific soil-borne diseases when inoculated alone,but it is not clear whether the combination of the two is better than a single strain.In this study,highly pathogenic F.oxysporum YFW32 was isolated from ginseng glacial lesions,and P.citrinum YW322 and T.velutinum YW411 strains were isolated and identified from ginseng rhizosphere soil,and their inhibitory efficiency against F.oxysporum was determined by in vitro culture evaluates experiments.Pot experiments were then conducted to investigate the effect of single or co-inoculation treatments on controlling ginseng root rot caused by F.oxysporum.To lay the foundation for the construction of efficient and stable microbial agents against ginseng root rot.The main findings of the study are as follows:（1）The results of the plate confrontation showed that the inhibition rates of P.citrinum YW322 and T.velutinum YW411 against F.oxysporum were 83.44%and 81.48%,respectively.Further investigation of the inhibitory activity showed that the inhibition rates of P.citrinum culture filtrate was 56.50%;the inhibition rates of T.velutinum culture filtrate was 10.76%.The above results showed that the in vitro culture of P.citrinum had a more potent inhibitory effect on F.oxysporum than T.velutinum.（2）Phenotypic analysis of the pot experiment showed that inoculation with either P.citrinum or T.velutinum could inhibit ginseng root rot caused by F.oxysporum.The quantitative results of the biological characteristics of ginseng showed that the inoculation with T.velutinum increased the aboveground part and root fresh weight of ginseng by 44.91%and 32.31%,respectively,compared to the control,and the co-inoculation with P.citrinum and T.velutinum had no growth-promoting effect.This suggests that T.velutinum can promote the growth of ginseng,while co-inoculation with P.citrinum and T.velutinum inhibited the growth-promoting effect of T.velutinum.（3）Analysis of the ginseng endophytic microbial community indicated that inoculation of P.citrinum or T.velutinum alone could regulate the structure of the ginseng endophytic microbial community by reducing the relative abundance of potential pathogenic bacteria in plant roots and promoting the enrichment of potential probiotic bacteria in plant roots.Inoculation of P.citrinum alone significantly reduced the relative abundance of Fusarium in plant roots,compared to co-inoculation of P.citrinum and T.velutinum,which significantly increased the relative abundance of Fusarium in plant roots.This indicates that co-inoculation of P.citrinum and T.velutinum reduced the inhibitory effect of P.citrinum on Fusarium.（4）The results of physicochemical and microbial community analysis of ginseng rhizosphere soil showed that inoculation of P.citrinum or T.velutinum alone regulated the soil microbial composition by reducing the relative abundance of potential pathogenic bacteria in rhizosphere soil,and enriching potential probiotic bacteria was promoted and increase in soil p H,TK concentration and S-CAT activity.Soil microbial composition was positively regulated to create a soil environment more conducive to ginseng growth,and thus resist infestation of F.oxysporum on ginseng.Inoculation of P.citrinum alone significantly reduced the relative abundance of Fusarium in the rhizosphere soil,while co-inoculation of P.citrinum and T.velutinum treatments significantly increased the relative abundance of Fusarium and reduced soil p H,NO₃^--N and NH₄⁺-N concentrations,Urease,S-CAT,S-SC and S-ACP activity all decreased.It further indicated that co-inoculation of P.citrinum and T.velutinum weakened the inhibitory effect of P.citrinum on Fusarium and reduced the enzyme activities of soil.