Biocontrol Effect and Culture Condition Optimization of Trichoderma citrinoviride Strain Isolated from Rhizosphere of Atractylodes lancea / 中国实验方剂学杂志

ABSTRACT

ObjectiveRoot rot is one of the most serious diseases in the cultivation and production of Atractylodes lancea. Trichoderma spp. are effective in the biocontrol of root rot without causing environmental pollution. This study aims to isolate and study a Trichoderma strain capable preventing and controlling root rot from the rhizosphere of A. lancea and to solve the problem of disease prevention and control in the planting and production of A. lancea. MethodTrichoderma T2204 was isolated by the dilution-coating method and identified by ITS sequencing. The inhibitory activities of T2204 and its volatiles against two pathogenic fungal strains were examined by dual-culture and co-culture experiments. The biocontrol potential of T2204 on root rot of A. lancea and the effect of T2204 on the accumulation of medicinal compounds in the rhizosphere of A. lancea were investigated by pot experiments and GC-MS， respectively. In addition， the optimal medium， photoperiod， temperature， pH， and carbon and nitrogen sources for the culture of T2204 were explored. ResultThe Trichoderma isolate T2204 was identified as T. citrinoviride and had direct inhibitory effects on two highly pathogenic strains causing root rot. In the dual-culture experiments with the two pathogenic strains， T2204 showcased the inhibition rates of 77.90% and 76.80%， respectively. In the co-culture experiments with the two pathogenic strains， the volatile organic compounds produced by T2204 showed the inhibition rates of 57.11% and 81.11%， respectively. The pot experiments showed that the survival rate of A. lancea seedlings infected by root rot reached 100% after inoculation with T2204 and was only 50% in the case without inoculation of T2204. After 150 days of cultivation， the dry weight and atractylodin content of the rhizome of A. lancea plants treated with T2204 increased by 32% （P<0.05） and 11%， respectively， compared with the untreated group. The optimal conditions for the growth of T2204 were PDA or PSA medium， photoperiod of 12 h dark/12 h light， 25-30 °C， pH 5-6， carbon sources of glucose， D-fructose， soluble starch， and maltose， and the nitrogen sources of ammonium sulfate and ammonium dihydrogen phosphate. The optimal conditions for the sporulation of T2204 were PSA or CMA medium， photoperiod of 12 h dark/12 h light， 20-30 °C， pH 8， carbon source of sucrose， and nitrogen source of sodium nitrate. ConclusionT2204 could improve the growth and root rot resistance of A. lancea and promote the accumulation of medicinal compounds. The findings laid a foundation for the industrialized production and application of T2204 in the production of A. lancea in the future.