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菌物学报 2012
Biological characteristics of the pathogenic-related deletion mutant △Focr1-328 of Fusarium oxysporum f.sp.cubense race 1
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Abstract:
Fusarium wilt of banana(Musa spp.),caused by Fusarium oxysporum f.sp.cubense race 1,is the most important factor limiting the plantation of plantain banana(AAB Group Fenjao) on the large scale.The pathogenic mechanism is still not very clear yet.A nonpathogenic mutant Focr1-328 with a T-DNA insertion was recently obtained.The inactivated gene resulting from a T-DNA insertion was located in the genomic sequences of Focr1.Subsequently,the gene was knocked out and a deletion mutant △Focr1-328 was obtained by homologous recombination.In order to investigate the function of the pathogenic related gene,the pathogenicity of the wild type Focr1-N2 and the deletion mutant △Focr1-328 was tested by inoculating living leaves and roots with spore suspension.The differences in the colony morphology,mycelial growth and conidial production on PDA,the growth rates and morphology on different carbon and nitrogen sources and the biomass,potential of hydrogen value,optical density value as well as cellophane penetrating capability were studied.The results of pathogenicity experiments showed that the deletion mutant △Focr1-328 was nonpathogenic,indicating that △Focr1-328 lost the pathogenic capability.The growth rate,the quantity and germination rate of conidia and the biomass of mycelia of the deletion mutant △Focr1-328 were significantly lower than those of wild type.The best carbon sources for the mutant and the wild type growth was sorbitol and maltose,respectively.The optimum Nitrogen source was sodium nitrate in both cases but the growth rates and colors of mutant and wild type were different on various C and N media.The wild strain penetrated cellophane readily,but the mutant could not.The results indicated that pathogenic related gene which was inactivated by T-DNA insertion is related to the utilization of C source,acid production and mycelial penetration capability.
