Construction of an unmarked genetically engineered strain Bacillus subtilis WB800-ipaH capable of degrading iprodione and its pilot application

Abstract

Residues of iprodione, used for the control of fungal diseases in crops, endanger both human health and ecosystem functioning. In this study, we isolated an iprodione-degrading bacteria, Pseudarthrobacter sp. Y-5, able to grow on iprodione as the sole carbon source. To achieve the high-level stable synthesis of iprodione hydrolase (IpaH), an unmarked genetic engineering approach was used to construct Bacillus subtilis WB800-ipaH, which showed the extracellular secretion and expression of the ipaH gene. Strain WB800-ipaH had superior degradability and showed cost-effectiveness potential for the bioremediation of iprodione-polluted environments than those of strain Y-5. Furthermore, iprodione suppressed Chlorella ellipsoidea growth and was toxic to Daphnia magna, while strains Y-5 and WB800-ipaH were both capable of degrading iprodione to relieve its toxicity. Both Y-5 (107 CFU g−1 soil) and WB800-ipaH (105 CFU g−1 soil) could eliminate >90% of 5 and 20 mg kg−1 iprodione in field soil within 9 d and 15 d, respectively. This work provides strain resources for eliminating the residue of iprodione in the environment.