Background work and knowledge
Fusarium oxysporum is a host specific soilborne fungi, it attacks many important crops, vegetables and fuits, for example: melon, tomato, cucumber etc. and causes vascular wilt diseases, crown and root rots, wilt disease (Kaur, 2010). Nonpathogenic F. oxysporum is a strain of F. oxysporum which does not attack plants in the soil. These nonpathogenic strains play an important role is supressing F. oxysporum, therefore it is an effective biocontrol agent of F. oxysporum.
Despite this adavantages it less known whether the release of the nonpathogenic strains will cause any harm in ecosystem. Therefore more research needed to identify the whole genetic data of it with molecular genetic testing so people should not worry about using nontpathogen F. oxysporum as a biological control agent (Fravel, 2003).
2. Nonpathogenic Fusarium Oxysporum
Nonpathogenic F. oxysporum is a strain of pathogenic F. oxysporum which colonize the root of healthy plants without any symptoms. This nonpathogenic strain was first isolated from fusarium-wilt suppressive soils, which contain many antagonistic microorganisms that suppress soil-borne diseases (Nel, 2006). It can succesfully suppress fusarium diseases because of its ability to compete for carbon and iron more efficiently (Lemanceau, 1993). Furthermore it can compete for root colonization and can induce systemic resistance. Induced systemic resistance means that plants can protect themselves against microbial infections with a defensive response (Fravel, 2002). Based on observations, the persence of the pathogen is less when the nonpathogenic strain present in the soil (Olivain 1997).
3. The problem
Cook et al. (1996) has written about four issues in his paper that biocontrol agents can have unexpected and harmful effects on nontarget organisms. These issues are competitive displacement, which can cause extinction of a population, allergenicity as a result of released biocontrol agent to the open air with its pollen and spores, toxigenicity which can be harmful for animlas and pathogenicity to nontarget organisms.
The most likely problems can be regarding with non-pathogenic F. oxysporum that it is possible that some Fusarium produce harmful mycotoxins, another problem is what if the non-pathogenic strain will be pathogenic in a living soil environment to different plants and what if new races of the pathogen arise (Fravel, 2003).
These four issues and likely problems are significant to consider if we would like to release nonpathogenic F. oxysporum. So far researchers mostly studied this strain in laboratory and greenhouse environment but to have a functioning biocontrol agent we need to know the possible effects of non-pathogenic F. oxysporum on the ecosystem by molecular genetic testing and by testing possible strains on nontarget plants.
1. Genetic analyses with PCR of non-pathogenic Fusarium oxysporum to assess genetic variation.
2. Risk-assessment of...