Fusarium Species from Nepalese Rice and Production of Mycotoxins and Gibberellic Acid by Selected Species

Abstract

Infection of cereal grains with Fusarium species can cause contamination with mycotoxins that affect human and animal health. To determine the potential for mycotoxin contamination, we isolated Fusarium species from samples of rice seeds that were collected in 1997 on farms in the foothills of the Nepal Himalaya. The predominant Fusarium species in surface-disinfested seeds with husks were species of the Gibberella fujikuroi complex, including G. fujikuroi mating population A (anamorph, Fusarium verticillioides), G. fujikuroi mating population C (anamorph, Fusarium fujikuroi), and G. fujikuroi mating population D (anamorph, Fusarium proliferatum). The widespread occurrence of mating population D suggests that its role in the complex symptoms of bakanae disease of rice may be significant. Other common species were Gibberella zeae (anamorph, Fusarium graminearum) and Fusarium semitectum, with Fusarium acuminatum, Fusarium anguioides, Fusarium avenaceum, Fusarium chlamydosporum, Fusarium equiseti, and Fusarium oxysporum occasionally present. Strains of mating population C produced beauvericin, moniliformin, and gibberellic acid, but little or no fumonisin, whereas strains of mating population D produced beauvericin, fumonisin, and, usually, moniliformin, but no gibberellic acid. Some strains of G. zeae produced the 8-ketotrichothecene nivalenol, whereas others produced deoxynivalenol. Despite the occurrence of fumonisin-producing strains of mating population D, and of 8-ketotrichothecene-producing strains of G. zeae, Nepalese rice showed no detectable contamination with these mycotoxins. Effective traditional practices for grain drying and storage may prevent contamination of Nepalese rice with Fusarium mycotoxins.

Real-Time PCR and Agar Plating Method to Predict Fusarium Verticillioides and Fumonisin B1 Content in Nigerian Maize

“…verticillioides can be an endophyte in maize, the production of fumonisin depends not only on the presence of the fungus, but also on the correct environmental conditions for the strains present to be able to make the toxin. Fumonisin non-producing strains from field samples are known (Desjardins et al 2000), but in general the proportion of these strains to the total population is relatively small. Other explanation for samples with the fungus but no toxin may be because the fungus appeared late and did not have time to produce the toxin or that it was misidentified.…”

Detection of fumonisin producing Fusarium verticillioides in paddy (Oryza sativa L.) using polymerase chain reaction (PCR)

“…Fusarium infection and fumonisin contamination is a major problem in Pakistan and 20% of the seeds were found naturally infected by F. verticillioides (4). Desjardins et al (2000) have reported 2980μg/g of fumonisin production from rice culture. This indicates that, even 20% of F. verticillioides infection can be a serious problem, as paddy is the staple food for people of Asia.…”

“…In Asia, the incidence of Fusarium and fumonisin contamination is highly prevalent. F. verticillioides contamination has been reported from Nepal, where both local and improved varieties of paddy are affected by F. verticillioides (8).…”

Integration of Seed Treatments, Seedling Dip Treatments and Soil Amendments for the Management of Bakanae Disease in Paddy Variety Pusa Basmati 1121

“…Bakanae or foot rot disease of rice has been recorded in almost all rice growing countries, especially in Asian countries (Desjardins et al, 2000). Bakanae disease was widespread in Peninsular Malaysia and three provinces of Indonesia with the range of disease severity from scale 1-5 and disease incidence from 0.5-12.5% during 2004-2005 main growing seasons (Zainudin et al, 2008) but the disease may be responsible for yield losses of up to 50% in Asia in outbreak cases.…”

“…J., 14 (4): 207-211, 2015 stimulating substances known as gibberellins, which are responsible for excessive elongation of the plants (Malonek et al, 2005). Besides gibberellins, the fungus also produces a phytotoxin, fusaric acid, a non-specific substance which is toxic to the plants (Desjardins et al, 2000). The name "Bakanae" comes from a Japanese word, meaning abnormal elongation of the plants.…”