Aspergillus texensis: A Novel Aflatoxin Producer with S Morphology from the United States

Area of Science:

• Mycology
• Plant Pathology
• Food Safety

Background:

• Aflatoxins are carcinogenic fungal metabolites produced by Aspergillus section Flavi.
• These fungi pose a significant threat to crops in warm climates worldwide.
• Previous research has primarily focused on known aflatoxin-producing species.

Purpose of the Study:

• To identify novel aflatoxin-producing fungal species within Aspergillus section Flavi in the US.
• To characterize the morphology, physiology, and phylogenetic placement of newly discovered species.
• To assess the aflatoxin production capabilities of the novel species.

Main Methods:

• Molecular phylogenetic analyses using β-tubulin, calmodulin, and nitrate reductase gene sequences.
• Isolation and culturing of fungi from maize and soil samples across the US.
• Morphological characterization and physiological studies (optimal growth temperature).
• Quantification of aflatoxin and cyclopiazonic acid production.

Main Results:

• Discovery and description of a novel aflatoxin-producing species, Aspergillus texensis.
• Aspergillus texensis was isolated from maize and associated soils in Arkansas, Louisiana, and Texas.
• All isolates produced B and G aflatoxins, cyclopiazonic acid, and aspergillic acid.
• Aspergillus texensis showed similar aflatoxin production levels to Aspergillus flavus S strains on maize.
• Phylogenetic analyses placed Aspergillus texensis in a distinct clade related to Aspergillus minisclerotigenes.

Conclusions:

• Aspergillus texensis represents a newly identified source of aflatoxin contamination in US crops.
• This discovery expands our understanding of aflatoxin-producing fungi diversity.
• Further research is needed to assess the ecological role and agricultural impact of Aspergillus texensis.