title: Characterization of non-aflatoxigenic strains of Aspergillus flavus as potential biocontrol agent for the management of aflatoxin contamination in groundnut.
abstract: In the present study, nine non-aflatoxigenic Aspergillus flavus strains were evaluated for their potential to reduce A. flavus infection and aflatoxin contamination in groundnut. Genetic characterization of these strains revealed six different deletion patterns (A-F) for thirteen examined genes from the aflatoxin biosynthesis pathway. Strain AFGS5 recorded maximum number of gene deletion (F) which included 12 out of 13 tested genes. Our findings indicated that aflR was the most frequently absent gene among the observed deletion patterns. A dendrogram inferred from combining random amplified polymorphic DNA and microsatellite data showed three of the non-aflatoxigenic strains segregating from other sampled isolates (aflatoxigenic and non-aflatoxigenic) tested. Greenhouse experiments, involving non-aflatoxigenic strains as biocontrol agents resulted in two strains, AFGS5 and AFGS12, which significantly reduced the population of aflatoxigenic fungi and the level of total aflatoxins in the rhizosphere/geocarposphere of soil samples as well as in groundnut seeds. Based on our findings, the use of these native non-aflatoxigenic strains; AFGS5 or AFGS12 in particular, as biopesticides could offer efficacious mitigation of aflatoxin contamination.
authors.affiliation: Department of Biotechnology, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka, India.
authors.forename: Navya
authors.initials: N
authors.lastname: Hulikunte Mallikarjunaiah
authors.affiliation: Department of Biotechnology, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka, India.
authors.forename: Naveen
authors.initials: N
authors.lastname: Jayapala
authors.affiliation: Centre for Rural Development and Technology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Puttaswamy
authors.affiliation: Department of Biotechnology, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka, India. Electronic address: lifescience129@gmail.com.
authors.forename: Niranjana
authors.initials: N
authors.lastname: Siddapura Ramachandrappa
mesh_terms: D000348:Aflatoxins / Q000096:biosynthesis*; D010367:Arachis; D001231:Aspergillus flavus / Q000145:classification* / Q000502:physiology*; D005506:Food Contamination; D005516:Food Microbiology; D005800:Genes, Fungal; D018895:Microsatellite Repeats; D005810:Multigene Family; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D017384:Sequence Deletion
chemical_list: D000348:Aflatoxins
keywords: Biopesticides; Deletion pattern; PCR; Rhizosphere