Genetic characteristics of Fusarium verticillioides from corn in the Philippines

Abstract

Fusarium verticillioides (teleomorph: Gibberella moniliformis = G. fujikuroi mating population A) is one of the most important fungal pathogens of corn worldwide. The pathogen produces fumonisins, mycotoxins that are potentially harmful to humans and animals. Thirty-five Fusarium isolates from Laguna and Isabela, Philippines were identified morphologically and molecularly as F. verticillioides and characterized by PCR for mating type (MAT). Twenty-six isolates were MAT1-2, while nine isolates were MAT1-1. The isolates from Isabela were tested for aggressiveness, rated according to a disease index (%) on 'Super Sweet' corn IPB variety 1 under field conditions across two trials using the toothpick inoculation method. Other aggressiveness traits such as inhibition of seedling emergence, decrease of seedling height, fresh and dry mass were also determined in two greenhouse trials. All isolates were pathogenic to corn seedlings and mature plants compared to the noninoculated control. Significant genotypic variation was observed (P = 0.01) in trial, isolate, and isolate 9 trial interaction for all traits across two greenhouse trials and that aggressiveness was highly influenced by the trial conditions. Similarly, significant genotypic variation was observed in trial, replication within trial and isolate 9 trial interaction. Heritability was high for the five traits in the greenhouse (h 2 = 0.80-0.90) but moderate for disease index in the field (h 2 = 0.49). In an analysis of fumonisin production in corn culture by high performance liquid chromatography, 30 of 35 strains produced a detectable level of fumonisins, varying from 0.44 to 742 lg FB 1 /g corn, 0.51-222 lg FB 2 /g and 0.12-37 lg FB 3 /g. Isabela isolates produced more fumonisins than the Laguna isolates did. In vitro fumonisin production had little correlation with the field disease index (r = 0.32) or with greenhouse seedling germination (0.25).

Phylogenetic analysis, fumonisin production and pathogenicity ofFusarium fujikuroistrains isolated from rice in the Philippines

“…On the other hand, our results indicated that fumonisin production and disease did not seem to be directly related, similarly to F. proliferatum in wheat . However, in the case of F. verticillioides in maize, the evidence is contradictory, suggesting that the role of fumonisins is far from being understood and might depend on the host considered. Production of mycotoxins, including fumonisins, might aid in colonization of plant tissue and competition against other fungal species during infection, but their implication in bakanae disease symptoms is probably reduced.…”

Rhizospheric bacteria of maize with potential for biocontrol of Fusarium verticillioides

“…The experiment was evaluated 45 days after seed emergence. Root volume was measured according to Burdett ( 1979 ) and disease severity was evaluated as described in Cumagun et al ( 2009 ). An additional experiment was performed as a control to confirm that bacteria did not cause any detrimental effects to root volume; this experiment used a set of bacterial-treated seeds compared to an untreated seed control (receiving water) grown in sterile sand under the same conditions as listed above (data not shown).…”

Genetic diversity among Fusarium species associated with sorghum stalk rot in Southern Ethiopia

“…On the other hand, isolates belonging to the new species grew considerably faster (10-17 mm/day) at 25°C than at 30°C (7-12 mm/day). When five isolates representing F. andiyazi and 10 isolates from the new Fusarium species were used to inoculate the stalks of mature sorghum plants using the toothpick inoculation method (Cumagun et al, 2009), all of them produced typical lesions that were absent in the control plants. This suggested the pathogenicity of both species to sorghum and proved that they were responsible for the stalk rot of sorghum.…”