RESUMEN
An improved DNA-mediated transformation system for nematode-trapping fungus Arthrobotrys oligospora based on hygromycin B resistance was developed. The transformation frequency varied between 34 and 175 transformants per microg linearized DNA and 93% of the transformants were stable for drug resistance when tested 100 randomly selected transformants. More than 2000 transformants were obtained by transformation of the fungus with pBChygro in the presence of HindIII and among them, one, YMF1.00110, which lost its ability of forming predacious structure, was isolated. Southern analysis showed that the plasmid DNA had integrated into the genome of all tested transformants (including YMF 1.00110) except one. The transformant tagged with hph gene could be re-isolated and quantified from dung samples based on the resistance of hygromycin B. All the results suggested that the method of restriction enzyme mediated integration (REMI) should facilitate not only the insertional mutagenesis for tagging and analysis genes of interest but also the ecological investigation of tagged fungi in a given environment.
Asunto(s)
Ascomicetos/genética , Nematodos/microbiología , Transformación Genética , Animales , Ascomicetos/efectos de los fármacos , Southern Blotting , ADN de Hongos/química , ADN de Hongos/genética , Farmacorresistencia Fúngica , Higromicina B/farmacología , Mutagénesis InsercionalRESUMEN
The composition of volatile compounds of soils and that of soil bacterial metabolites were identified by using the SPME-GC/MS method. Results showed that some compounds, trimethylamine, 3-methyl-2-pentanoe, dimethyl disulfide, methyl pyrazine, 2,5-dimethyl-pyrazine, benzaldehyde, N,N-dimethyloctylamine and nonadecane, subsisted commonly in soils and soil bacterial metabolites with strong fungistatic activity. These compounds may be the key antifungal factors in soil fungistasis, especially soil volatile fungistasis. Otherwise, the method used in this study was a good tool for further study of soil volatle fungistasis.