| The fungal strains that inhibited and preventting disease caused by Phytophthora capsici from plants such as pepper and mangroves were mixed with the Bacillus amyloliquefaciens strain SH-27 associated with corals,which had strong antagonisms against P.sojae and P.capsici and had the growth-promoting to pepper and soybean seedings,to explore the combination of fungi and bacteria in the prevention of pepper phytophthora blight and promotion of pepper seedings.Thirty strains with inhibitory effects on Phytophthora capsici were screened from pepper and mangrove by dilution-separation method and plate-peel method.Seven fungi strains with strong inhibition rate,high growth rate and large sporulation rate were selected.The results of indoor control of pepper disease indicated that the TH-T20 strain from the root of Tung Blossom(Mangrove)was better and more stable.Based on morphological characteristics and ITS gene sequence analysis,the strain TH-T-20 was identified as Trichoderma asperellum.The TH-T20 strain and Bacillus amyloliquefaciens SH-27 strain alone treatment of pepper growth-promoting and preventing P.capsici indoor pot test results showed that with the increase of inoculation amount of TH-T20 strain its prevention effect has also increased,and stable;The longer the interval between inoculation with Phytophthora capsici strains,the better the preventing effect.However,after inoculation with Phytophthora capsici strains and treatment with TH-T-20 strain,there is no preventing effect,indicating that TH-T20 strain has certain prevention of pepper phytophthora blight,but no therapeutic effect.The SH-27 strain was inoculated with P.capsici immediately after its treatment,and its control efficacy after 4th,6th and 9th days was 70.81%,66.55% and 48.20%,respectively.In addition,plant height,stem diameter,and fresh weight of pepper reedings treated with TH-T20 strain or SH-27 strain were significantly higher than those of the control and showed good growth-promoting effects.The combination of TH-T20 and SH-27 strains in control of pepper phytophthora blight indoor pot test results showed that the two strains of different concentrations of the culture medium have different prevention effects,when the SH-27 bacteria liquid content is greater than or equal to the TH-T20 Spore suspension,The preventive effect of the mixed broth was higherthan that of the two single strains.On the contrary,it was lower than that of the two single strains,and was lower than that of the SH-27 strain;The mixed solution with 1:2 ratio of the TH-T-20 and SH-27 strains had the best prevention effect,and the control effects after 3,6,9 and 12 days were 60.0%,61.90%,40.99% and 39.34%,respectively.The results of different inoculation times showed that the longer the interval between inoculation with Phytophthora capsici and the SH27+TH-T20 treatment,the better the prevention effect,indicating that the mixed broth was the main preventive effect against the pepper phytophthora blight.The combination of TH-T20 and SH-27 strains of solid fermented material to prevent and control the pepper blight and the field test of pepper growth-promoting showed that the incidence of pepper blight was lower than that of the control and the two single strains after treatment with the two strains.The height,root length,and yield of pepper seedings were all improved compared with the control and the two single strain treatments.This shows that the two strains have a certain field preventing effect on pepper blight,and have a good promotion of pepper growth-promoting.The prevention mechanism of combination of TH-T20 and SH-27 strains controlling phytophthora blight showed that:TH-T20 and SH27 strains could colonize the rhizosphere of pepper reedings;after the two strains were mixed treatment,the activities of the defensive enzymes of pepper eedings such as CAT,POD,and SOD were basically similar to those of pathogens,with little change;however,the activity of PAL enzyme was significantly higher than that of pathogens. |
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