Epsilon Archive for Student Projects

Abstract

Fusarium head blight (FHB) is a ubiquitous wheat disease that causes high yield losses in the field. Control of this disease is challenging due to the multiple fungal species that can cause the disease. Although the disease can be triggered by F. avenaceum, F. culmorum, or Microdochium spp. among others, F. graminearum is considered to be the major causal agent.
In addition, European authorities are expected to reduce the use of pesticides, making FHB a challenging threat to crop safety and highlighting the need for an alternative in crop protection. As biopolymers could be an emerging tool in crop protection, we tested three different biopolymers (pectin, chitin and chitosan) to assess if they had any effect on the development of FHB disease symptoms. We also tested Epicoccum nigrum exudates since Epicoccum is an entophytic fungus found alongside Fusarium in plants with FHB, but has been shown to be non-pathogenic and even to produce secondary metabolites that may have antifungal properties and enhance plant immunity. Through leaf detached infection assays and an optimized image analysis pipeline, we tested the three selected biopolymers and exudates from different Swedish E. nigrum and Microdochium spp isolates in the infection development of F. avenaceum, F. culmorum and F. graminearum. Among the different treatments and the different Fusarium species tested, pectin inhibited F. graminearum the most, especially the necrosis caused by the pathogen; while chitosan showed a tendency to reduce the necrosis produced by all studied Fusarium species.
In the case of the exudates, the results were highly dependent on both the exudate and the Fusarium species, yet we found some promising effects in inhibiting disease development.
These results open the door to further studies focusing on the molecular changes in pectin-treated plants compared to control plants to elucidate the mechanisms on which the observed reduction of FHB disease severity symptoms is acting. As well as fine-tune studies on the different exudates of interest in both single and co-infections with Fusarium.