Molecular profile of aflatoxigenic and non-aflatoxigenic isolates of Aspergillus flavus isolated from stored maize

Abstract

Maize is a significant staple crop and utilized in Saudi Arabia as food and feed, but maize is often infected with Aspergillus flavus in tropical and subtropical climates, especially during storage. This study intended at a polyphasic approach, consisting of microscopic morphological, biochemical, and molecular characterizations that were applied to 29 of A. flavus isolates of stored maize, with the goal of characterization and identification of aflatoxigenic and non-aflatoxigenic A. flavus isolates. The technique of real-time PCR (RTi-PCR) was used to detection of A. flavus in stored maize samples, the findings have been very accurate. Centered on macroscopic morphological (primarily colony color and morphology of conidia) and microscopic (morphology of conidia and size) characteristics. Results have shown 23 A. flavus isolates (80%) were categorized as the dark green of colonies also all isolates were rough conidia. The isolates have been two different groups, 16 isolates (62%) had sclerotium-forming and the remaining 13 isolates (38%) had no sclerotium-forming isolates. To the identification of aflatoxigenic isolates of A. flavus in stored maize, we utilized the qualitative methods (easy and inexpensive) like UV test, yellow pigmentation, and ammonia vapor and quantitative method as HPLC (accurate and expensive). the accuracy methods to the identification aflatoxigenicity isolates, vary, and classified in the following descending order: HPLC (100%) > UV method (81%) > yellow pigmentation (YP) and ammonia vapor (AV) (63%). The profile of Aflatoxigenicity of A. flavus isolates by HPLC has been involved in two types first of 11 isolates (38%) have been aflatoxigenic isolates while 18 isolates (62%) were non-aflatoxigenic isolates. The expression of six aflatoxins (AFs) genes ( aflD , aflM , aflO , aflP , aflR , and aflQ ) was estimated using PCR and RT-PCR. PCR of all genes did not correspond to the aflatoxigenic isolates. The transcriptional analysis of aflO and aflQ was a beneficial marker for discriminating aflatoxigenic from non-aflatoxigenic A. flavus isolates. Also, qRT-PCR indicated that non-aflatoxigenic isolates had a high incidence of defect or downregulation in late AF-genes contrast with early AF-genes. therefore, these non-aflatoxigenic isolates could be critical factors for an efficient and competent strategy for the control of aflatoxin contamination pre-harvest can be considered.

Aflatoxin levels and Aspergillus species in maize in the Province of Isabela, Philippines

“…The aflatoxigenic and non‐aflatoxigenic species of A. flavus are mostly correlated with their ability to produce sclerotia (El‐Aziz et al, 2021; Hua et al, 2012). It was reported that A. flavus L and S morphotypes produce primarily aflatoxin B1 (AFB1) and B2 (AFB2).…”

“…Further studies are warranted to determine whether the L‐morphotypes isolated in this study can be used as biological agent against toxigenic Aspergillus species. In many countries, sclerotium‐forming species of A. flavus , particularly the L‐morphotype, are being tested for their inability to produce aflatoxin and their potential use as a biological agent in control of aflatoxigenic A. flavus (Camiletti et al, 2018; Chofamba, 2021; El‐Aziz et al, 2021; Zanon et al, 2018; Zhang et al, 2020).…”

Role of RNA Modifications, Especially m6A, in Aflatoxin Biosynthesis of Aspergillus flavus

“…80 The expression pattern of aflQ was found to be correlated with the amounts of AFB1 in A. flavus. 81,82 However, the function of aflQ in A. flavus is still unclear. In this study, we found that the af lQ gene was important for the fungal growth, reproduction, mycotoxin production, and colonization of A. flavus on both artificial media and crop kernels (Figures 6 and 7).…”

Cumulative Effects of Non-Aflatoxigenic Aspergillus flavus Volatile Organic Compounds to Abate Toxin Production by Mycotoxigenic Aspergilli

“…Compounding the issue of contamination are climate extremes (e.g., extreme heat and drought) that increase crop susceptibility to infection by fungal pathogens [ 4 ]. Aspergillus flavus and closely related species from the genus’ section Flavi are some of the more serious fungal pathogens impacting global economics and health [ 5 , 6 ] due to their ability to infect staple food crops and produce harmful mycotoxins, such as aflatoxin. Therefore, researchers around the globe are developing strategies to prevent these toxin-producing fungi from infecting crop hosts and contaminating them with mycotoxins [ 7 , 8 ].…”