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Title: Analysis of genetic and aflatoxin diversity among Aspergillus flavus isolates collected from sorghum seeds

item DIVAKARA, S - University Of Mysore
item AIYAZ, M - University Of Mysore
item Moore, Geromy
item VENKATARAMANA, M - Bharathiar University
item HARIPRASAD, P - Central Food Technological Research Institute
item NAYAKA, S - University Of Mysore
item NIRANJANA, S - University Of Mysore

Submitted to: Journal of Basic Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2015
Publication Date: 6/23/2015
Citation: Divakara, S.T., Aiyaz, M., Moore, G.G., Venkataramana, M., Hariprasad, P., Nayaka, S.C., Niranjana, S.R. 2015. Analysis of genetic and aflatoxin diversity among Aspergillus flavus isolates collected from sorghum seeds. Journal of Basic Microbiology. 55:1255-1264.

Interpretive Summary: Sorghum bicolor is an important cereal crop in India that is susceptible to fungal colonization by Aspergillus flavus. Seeds are inadvertently planted which lead to increased risk of aflatoxin contamination and economic loss. This study aimed to evaluate and analyze the genetic diversity, and to establish the toxin profiling of, A. flavus strains recovered from sorghum seeds sampled in India. Findings show the majority of sampled A. flavus isolates were highly toxigenic, and also highly diversified in terms of toxin-producing potential, in-vitro. Genetic diversity among the sorghum isolates of A. flavus further warrants the development of appropriate farming management practices as well as improved aflatoxin detection measures in India.

Technical Abstract: A total of 34 A. flavus isolates were recovered from sorghum seeds sampled across five states in India. Our study included (1) species confirmation through PCR assay, (2) an aflatoxin cluster genotype assay using developed multiplex PCR, (3) quantification of total aflatoxin concentrations by the iC-ELISA method, and (4) analysis of molecular diversity among the A. flavus isolates using ITS and ISSR markers. Among the isolates studied, 28 were found to be positive for all assayed genes as well as for the production of aflatoxins. ITS phylogenetic analysis separated the A. flavus sample population into two major groups or clades with little to no subdivision based on geography. In contrast, ISSR analysis separated the A. flavus isolates into two main clusters, showing a distance of 0.0-0.5, with one cluster exhibiting a high level of diversity though no geographic subdivision could be observed.