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

• Published in: Journal of basic microbiology Vol. 55; no. 11; pp. 1255 - 1264
• Main Authors: Divakara, S. T, Aiyaz, M, Moore, G. G, Venkataramana, M, Hariprasad, P, Nayaka, S. Chandra, Niranjana, S. R
• Format: Journal Article
• Language: English
• Published: Germany Akademie-Verlag 01.11.2015; Blackwell Publishing Ltd
• Subjects: Aflatoxins; Aflatoxins - analysis; Aflatoxins - chemistry; Aspergillus flavus; Aspergillus flavus - chemistry; Aspergillus flavus - classification; Aspergillus flavus - genetics; Aspergillus flavus - isolation & purification; chemotypes; Enzyme-Linked Immunosorbent Assay; farming systems; Genetic diversity; Genetic Variation; geography; India; Inter-simple sequence repeats; internal transcribed spacers; microsatellite repeats; Phylogeny; Polymerase Chain Reaction; seeds; Seeds - microbiology; Sorghum; Sorghum - microbiology; tubulin; India; Aflatoxins; Inter-simple sequence repeats; Sorghum; Genetic diversity
• ISSN: 0233-111X; 1521-4028
• DOI: 10.1002/jobm.201400951

Thirty‐four Aspergillus flavus isolates were recovered from sorghum seeds sampled across five states in India. Our study included (1) species confirmation through PCR assay, (2) quantification of total aflatoxin concentrations by the indirect competitive‐ELISA (ic‐ELISA) method, and (3) analysis of molecular diversity among the A. flavus isolates using β‐tubulin, ITS, and ISSR markers. Among the isolates studied, 28 were found to be positive for the production of aflatoxins. ITS and β‐tubulin phylogenetic analysis segregated the A. flavus sample population into two major groups or clades with little to no subdivision based on geography. In contrast, ISSR analysis also 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 or chemotype subdivision could be observed. 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.