Extinguishing fire blight with the sea: potential of the invasive seaweed Asparagopsis Armata against Erwinia amylovora

Student name: Alexandra Lopes

RUN-EU institution: Technological University of the Shannon: Midlands Midwest, Ireland

Abstract

Fire blight is a harmful disease that causes necrosis in plants and primarily targets pome fruit trees within the Rosaceae family, but also affects wild and ornamental species, further increasing its impact on ecosystems. Since its discovery, fire blight has been recognised as the most devastating disease affecting pome fruit trees, strongly impacting the production of two of the most important fruits in the European Union: apples and pears. In Portugal, although both crops are affected, the “Rocha Pear,” an indigenous variety of great economic importance, has suffered a more severe impact. The causative agent of this disease is Erwinia amylovora, a gram-negative enterobacterium. To date, the use of antibiotics and copper-based compounds remains the most effective way of controlling fire blight. However, these methods are currently subject to strict regulations in the EU due to concerns about public health, the environment, and bacterial resistance. Thus, innovative approaches to managing the disease in a sustainable manner are urgently required. Asparagopsis armata, an aggressively invasive seaweed (Rhodophyta), was recently demonstrated to have strong antibacterial activity against E. amylovora using an ethanolic crude extract. From a sustainability perspective, exploring its potential as a biopesticide constitutes a strategic way of adding value to the biomass of invasive species from the Portuguese coast and finding eco-friendly solutions to the problematic under consideration. In the present work, the sustainability of the antimicrobial activity of the crude ethanolic extract against E. amylovora will be assessed under in vivo and field conditions. Additionally, the biostimulant/biofertilizer potential of the residual biomass from the extraction process will be tested in Solanum lycopersicum.