Effects of methamidophos on the community structure, antagonism towards Rhizoctonia solani, and phlD diversity of soil Pseudomonas

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Pesticides, food contaminants, and agricultural wastes, 2010-04, Vol.45 (3), p.222-228
• Main Authors: Wu, Minna, Li, Xinyu, Zhang, Huiwen, Cai, Yinghui, Zhang, Chenggang
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; amplified ribosomal DNA restriction analysis (ARDRA); antagonism; Antibiosis; Bacteria; Biodiversity; Biological and medical sciences; Chemical compounds; community structure; dose response; Dose-Response Relationship, Drug; Ecosystem; Environment; Environmental science; Fundamental and applied biological sciences. Psychology; genes; in vitro studies; Insecticides - pharmacology; Methamidophos; microbial genetics; Organothiophosphorus Compounds - pharmacology; phlD; Phytopathology. Animal pests. Plant and forest protection; plant pathogenic fungi; Population Dynamics; provenance; Pseudomonas; Pseudomonas - physiology; Rhizoctonia - growth & development; Ribosomal DNA; Soil and water pollution; soil bacteria; soil microbial community; Soil Microbiology; Soil science; soil-borne diseases; Soils; species diversity; Thanatephorus cucumeris
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601231003613609

A microcosm incubation study using an aquic brown soil from northeast China (a Cambisol in the UN Food and Agriculture Organization FAO Soil Taxonomy) was conducted to examine the effects of different concentrations (0, 50, 150, and 250 mg kg −1 ) of methamidophos (O,S-dimethyl phosphoramidothioato) on Pseudomonas, one of the most important gram-negative bacteria in soil. Amplified ribosomal DNA restriction analysis (ARDRA) was performed to study the Pseudomonas community structure, an in vitro assay was made to test the antagonistic activity of isolated Pseudomonas strains against soil-borne Rhizoctonia solani, a major member of the pathogens highly related to soil-borne plant diseases, and special primer amplification and sequencing were performed to investigate the diversity of phlD, an essential gene in the biosynthesis of 2, 4-diacetylphloroglucinol (2, 4-DAPG), which has biocontrol activity in phlD + isolates. With exposure to increasing methamidophos concentrations, the total number of soil Pseudomonas ARDRA patterns decreased significantly, but with less change in the same treatments over 1, 3, and 5 weeks of incubation. The number of isolated Pseudomonas strains with antagonistic activity against R. solani as well as the diversity and appearance frequency of the strains' phlD gene also decreased with increasing concentrations of methamidophos, especially at high methamidophos concentrations. Applying methamidophos could increase the risk of soil-borne plant diseases by decreasing the diversity of the soil Pseudomonas community and the amount of R. solani antagonists, particularly those with the phlD gene.