Diversity and Toxigenicity of Mycobiota in Grain Corn: A Case Study at Pioneer Grain Corn Plantations in Terengganu, Malaysia

Abstract

Malaysia has begun to locally mass-cultivate grain corn to reduce import dependency for animal feed industries. Since the Malaysian tropical climate constantly exposes grain corn to fungal colonization and mycotoxin production by mycotoxigenic species, it is, therefore, important to investigate the presence of fungal species, especially the mycotoxigenic strains in the Malaysian grain corn agroecosystem. In the present work, corn kernel, tassel, plant debris, and soil were collected from two pioneer grain corn farms (Kampong Dadong, KD; Rhu Tapai, RT), and morphological and molecular identifications were conducted. A total of 131 fungal isolates from 30 fungal species were recovered. Both KD and RT yielded log 4.7–6.7 CFU/g total fungal loads. Fusarium verticillioides was predominant in both farms, followed by the phytopathogenic Lasiodiplodia theobromae and the mycotoxigenic Aspergillus flavus, A. niger, F. incarnatum, and F. proliferatum. Mycotoxin analyses by high-performance liquid chromatography revealed that among 30 mycotoxigenic isolates tested for aflatoxins, deoxynivalenol, fumonisins, HT-2, T-2, ochratoxins A, and zearalenone, approximately 25 of the isolates could produce at least one mycotoxin in vitro. The present work serves as a baseline for more comprehensive research to better predict and control fungal contamination and the subsequent mycotoxin accumulation in Malaysian grain corn agroecosystems.

Seasonal and Geographical Impact on the Mycotoxigenicity of Aspergillus and Fusarium Species Isolated from Smallholder Dairy Cattle Feeds and Feedstuffs in Free State and Limpopo Provinces of South Africa

“…Interestingly, our investigation, on the contrary, revealed that location had no significant ( p > 0.05) effect on the toxigenicity of the fungal isolates. Our results on the effect of location on the fungal mycotoxin profiling agree with those of Yazid et al [ 44 ], who found that agro-ecological location has no influence on AFB 1 formation by A. flavus invading grain corn farms (Kampong Dadong and Rhu Tapai) in Terengganu, Malaysia. The authors emphasized that the mycotoxigenicity of the fungal isolates is more dependent on fungal strain specificity than geographical locations.…”

“…A. niger has been documented as one of the major OTA producers of agricultural products [ 44 , 45 ]. However, OTA production by Aspergillus spp.…”

“…However, the study confirmed a low incidence of OTA, AFG 1, and AFG 2 [ 6 ]. As motioned previously, the failure of the tested fungal isolates to produce these toxins may be linked to the culture medium [ 38 ], strain specificity [ 44 ], or the absence of mycotoxin cluster genes in the fungal species [ 55 ].…”

Mycotoxigenic fungal growth inhibition and multi-mycotoxin reduction of potential biological control agents indigenous to grain maize

“…To lessen the country’s dependency on importation, the Ministry of Agriculture and Food Industries has gazetted grain maize as one of the five new wealth-generating crop commodities alongside coconut, durian, dairy, and culinary industries (Bank Negara Malaysia 2018 ). This entails more land exploitation for the mass-cultivation of grain maize, following which, two pioneer grain maize plantations have been established in Kampong Dadong (13 hectares cultivated area) and Rhu Tapai (3.8 hectares cultivated area) in Terengganu, Malaysia (Yazid et al 2021 ).…”

“…Among the primary challenges in developing and applying BCA is ensuring mycotoxin inhibition instead of mycotoxin stimulation which is common among mycotoxigenic fungal species in the face of habitat / nutrient competition with the applied BCA. In a previous work (Yazid et al 2021 ), we isolated and identified morphologically and molecularly several BCA candidates as well as characterising the mycotoxin potentials of several mycotoxigenic fungal species from two pioneer grain maize farms in Terengganu, Malaysia. In the present work, we therefore examined the antagonistic potential of those BCA candidates in vitro using the dual-culture assay on grain maize agar.…”