GWA Study Identifies Two Positive Regulators of Mycotoxin Fumonisin B1 Tolerance in Arabidopsis

Fumonisin B1 (FB1) is a toxic secondary metabolite produced by Fusarium species that commonly contaminates cereal crops, posing serious threats to crop productivity and food safety. In plants, FB1 inhibits ceramide synthase, disrupts sphingolipid metabolism, and induces growth inhibition and programmed cell death. Despite the agricultural importance of fumonisin contamination, genetic strategies to enhance FB1 tolerance or detoxification capacity in crops remain limited, largely due to an incomplete understanding of the underlying genetic determinants.

To identify genetic determinants associated with FB1 tolerance, we exploited natural variation in Arabidopsis thaliana and conducted a genome-wide association study (GWAS). Candidate genes were further examined using gene expression analyses and functional characterization of overexpression and SALK mutant lines.

GWAS revealed a significant association locus on chromosome 1 linked to FB1 tolerance. Two adjacent genes within this locus, AT1G14750 and AT1G14755, were identified as positive regulators of FB1 tolerance. Both genes were rapidly induced upon FB1 exposure. Functional analyses demonstrated that overexpression of either gene significantly enhanced tolerance to FB1-induced damage, whereas SALK mutant lines displayed increased sensitivity, manifested by enhanced growth inhibition and necrosis.

Our study identifies AT1G14750 and AT1G14755 as previously uncharacterized components of FB1 tolerance in Arabidopsis. These findings provide new insights into the genetic architecture of plant response to mycotoxin stress and establish a foundation for further studies on the molecular mechanisms underlying FB1 tolerance.