Distribution of active ingredients of a commercial aflatoxin biocontrol product in naturally occurring fungal communities across Kenya

Abstract

Human populations in Kenya are repeatedly exposed to dangerous aflatoxin levels through consumption of contaminated crops. Biocontrol with atoxigenic Aspergillus flavus is an effective method for preventing aflatoxin in crops. Although four atoxigenic A. flavus isolates (C6E, E63I, R7H and R7K) recovered from maize produced in Kenya are registered as active ingredients for a biocontrol product (Aflasafe KE01) directed at preventing contamination, natural distributions of these four genotypes prior to initiation of commercial use have not been reported. Distributions of the active ingredients of KE01 based on haplotypes at 17 SSR loci are reported. Incidences of the active ingredients and closely related haplotypes were determined in soil collected from 629 maize fields in consecutive long and short rains seasons of 2012. The four KE01 haplotypes were among the top ten most frequent. Haplotype H-1467 of active ingredient R7K was the most frequent and widespread haplotype in both seasons and was detected in the most soils (3.8%). The four KE01 haplotypes each belonged to large clonal groups containing 27-46 unique haplotypes distributed across multiple areas and in 21% of soils. Each of the KE01 haplotypes belonged to a distinct vegetative compatibility group (VCG), and all A. flavus with haplotypes matching a KE01 active ingredient belonged to the same VCG as the matching active ingredient as did all A. flavus haplotypes differing at only one SSR locus. Persistence of the KE01 active ingredients in Kenyan agroecosystems is demonstrated by detection of identical SSR haplotypes six years after initial isolation. The data provide baselines for assessing long-term influences of biocontrol applications in highly vulnerable production areas of Kenya.

Structure of Aspergillus flavus populations associated with maize in Greece, Spain, and Serbia: Implications for aflatoxin biocontrol on a regional scale

“…At the same time, these populations consisted of both locally restricted and widely dispersed common haplotypes among samples and among countries. Second, complete LD was observed in all countries (Table 2, Figure S4), supporting clonal evolution of A. flavus populations in southern Europe, as seen in other studies of natural populations of A. flavus (Grubisha & Cotty, 2015;Hadrich et al, 2013;Islam et al, 2018Islam et al, , 2020Ortega-Beltran et al, 2020;Picot et al, 2018). Finally, members of the VCG to which MUCL54911 belongs occur in all the sampled regions (Table 4), revealing a natural distribution of this biocontrol agent across southern Europe and opening the potential for use of MUCL54911 in the mitigation of aflatoxin contamination throughout this region.…”

Aflatoxin contamination of maize and groundnut in Burundi: Distribution of contamination, identification of causal agents and potential biocontrol genotypes of Aspergillus flavus

“… a Allele sizes indicate amplicon size in base pairs as called on an ABI 3730 DNA Analyzer with the LIZ500 standard (Applied Biosystems). Islam et al (2021) previously published data of Aflasafe KE01. However, the haplotype name and allele size of AF66 for active ingredient E63-I has been corrected in the Table.…”

“…Indeed, when the atoxigenic isolates were genotyped with SSR markers, a few SSR genotypes occurred in high frequency and in several provinces demonstrating wide distribution and hence potential of high adaptation in the country ( Table 3 ; Supplementary Table S1 ). An extensive Aspergillus population distribution study in Kenyan soil showed that the active ingredients of the biocontrol product Aflasafe KE01 are widely distributed in Kenya ( Islam et al, 2021 ). Isolates of some representative Burundi-specific SSR groups detected in the current study were tested in laboratory assays as potential candidates for the development of biocontrol products for aflatoxin management for use in Burundi ( Table 3 ).…”

“…indicate amplicon size in base pairs as called on an ABI 3730 DNA Analyzer with the LIZ500 standard (Applied Biosystems) Islam et al (2021). previously published data of Aflasafe KE01.…”

Multiple Year Influences of the Aflatoxin Biocontrol Product AF-X1 on the A. flavus Communities Associated with Maize Production in Italy

“…The residual influences of biocontrol products can be assessed by the multi-year monitoring of the AF- active ingredients in agricultural soils. This can be done by examining individual genotypes within the resident fungal population and characterizing those individuals with either culture-based (i.e., a vegetative compatibility analysis (VCAs) [ 20 , 50 ] or molecular tools, such as microsatellite analyses or SNP monitoring with pyrosequencing [ 51 , 52 , 53 ]. Moreover, several studies have previously identified the role of some aflatoxin biosynthesis pathway genes, such as omt -A and aflR , to develop new approaches to estimate the aflatoxin-producing capacity of Aspergillus spp., such as the use of real-time PCR [ 54 , 55 , 56 ].…”