Effects of elicitors on trichothecene accumulation and Tri genes expression in potato tubers inoculated with Fusarium sulphureum

Postharvest losses due to pathogens are a major concern in agriculture and therefore new strategies to reduce these losses while making sure that the treated products are safe for the consumer, are of paramount importance. Chemical fungicides treatment is not only unsafe but also leads to pathogen developing resistance. Therefore, products that can reduce the development of dry rot of potato and mycotoxin accumulation, and be safe are needed. A better understanding of the induction of trichothecene biosynthesis is essential to reduce trichothecene production. The effects of three elicitors such as beta-amino butyric acid (BABA), sodium silicate and chitosan, on the suppression of lesion development, trichothecene accumulation, and expression of Tri genes were assessed in potato tubers inoculated with Fusarium sulphureum. The results showed that lesion diameters were significantly reduced after treating with BABA at 100 mM for 3 d, sodium silicate at 100 mM for 2 d and chitosan at 0.50% for 3 d. Tri gene expressions were significantly down-regulated in inoculated tubers after elicitor treatments, and trichothecene accumulation were also suppressed. Meanwhile, the levels of trichothecene accumulation and Tri genes expression showed cumulative changes with the incubation time, extending after elicitor treatments. In addition, elicitor applications reduced more for type A trichothecene (T-2, DAS) than type B trichothecene (3ADON, Fus-X). It is possible that elicitors triggered downstream resistance genes to produce resistance related metabolites that suppressed the biomass of F. sulphureum, resulting in reduced Tri gene expressions and trichothecene accumulation.