Arbuscular mycorrhizal fungi from greenhouse pepper crops as potential biocontrol agents of Verticillium dahlia

Abstract

Arbuscular mycorrhizal fungi (AMF) are present in natural and agricultural systems and form one of the most common mutualistic symbioses occurring with plant species (Smith & Read, 2008). Their benefits involve improved nutrient uptake and protection against root pathogens (Smith et aI., 2010). Verticillium wilt is a disease caused by the soil-borne pathogenic fungus Verticillium dahliae and affects pepper (Capsicum annumm L.) crops in Galicia (NW Spain). In this work, AMF diversity and abundance in greenhouse soils used for pepper crops were analyzed, taking into consideration the recent record of both presence and absence of vascular wilt diseases (including Verticillium wilt) in pepper crops. AMF spores were directly analyzed from field soils and grouped into morphotypes, according to their morphological characteristics, such as shape, size and color. Differences in diversity and abundance of AMF morphotypes were found between healthy and diseased pepper soils. AMF community's diversity was measured by computational indices that combine both relative abundance and diversity and ANOVA statistical analysis between diversity parameters was carried out. The similarity between samples was also performed by a non-metric multidimensional scaling (NMDS) and discriminant morphotypes were found between healthy / diseased soils. Molecular analysis will be performed for each AMF morphotype to identify AMF species. A selection ofpotentialAMF species for acting as a biological control agent against V. dah/iae will be done, taking into consideration their ecological function, as well their presence/absence in healthy / diseased greenhouses. Future studies on controlling V. dahliae pathogen will determine their effectiveness as biocontrol agents, allowing the future reduction of agrochemicals use, while potentiating the use of soil organisms to increase agricultural/food production.