In order to screen for biocontrol microorganisms and natural products effective against Sphacelotheca reiliana infection in sorghum root tissue,and to develop a microbial suspension seed coating agent suitable for practical application in sorghum cultivation.In this study,Jinza 2001 sorghum and three excellent disease-resistant bacteria and natural product of lipopeptide were used as the experimental material.Firstly,the anti-infection effects and optimal concentrations of different disease-resistant bacte-ria and lipopeptide against S.reiliana were determined involving seed germination and in vivo infection rate determination.Sub-sequently,the optimal formulation,dosage,and storage stability of the suspension seed coating agent were studied based on the active ingredients of the optimum strain and lipopeptide.The anti-infection effect of suspended seed coating agent against SS.rei-liana was measured under potted conditions.Results showed that Bacillus velezensis G-1 and its secondary metabolites(lipopep-tide)exhibited significant efficacy against S.reiliana on infection in sorghum root tissue,with optimal concentrations of 1.0× 109 cfu mL-1 for B.velezensis G-1 and and 600 μg mL-1 lipopeptide,respectively.Moreover,there was no significant inhibitory effect on the germination of Jinza 2001 at the optimal concentrations of B.velezensis G-1 and lipopeptide(P＞0.05).The optimal for-mula for the B.velezensis G-1·lipopeptide suspension seed coating agent comprised of 5 mL of strain G-1(1.0 × 1011 cfu mL-1),5 mL of lipopeptide substance(8 mg mL-1),4 g of sodium carboxymethyl cellulose,0.6 g of sodium alginate,4 g of dispersant MF,0.2 g of ferrous sulfate,1 g of magnesium sulfate,0.5 g of potassium dihydrogen phosphate,4 g of color paste,and water added to reach 100 g.The optimal dosage of B.velezensis G-1·lipopeptide suspension seed coating agent was 25 g packaged with 1 kg sorghum seeds,resulting in the anti-infection effect for S.reiliana infecting sorghum root was 87.74％under pot test conditions.Additionally,the B.velezensis G-1·lipopeptide suspension seed coating agent demonstrated a positive promoting effect on the growth of sorghum seedlings and exhibited good storage stability.After 12 months of storage in dark and room temperature condi-tions,the anti-infection effect of B.velezensis G-1·lipopeptide suspension seed coating agent only decreased by 1.63％.In conclu-sion,B.velezensis G-1·lipopeptide suspension seed coating agent holds promising application prospects in the development of green prevention and control technology for sorghum head smut.
维普
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