Fusarium proliferatum secondary metabolite profile in vitro depends on the origin of the isolates and is clearly reduced in stored garlic

Abstract

Fusarium proliferatum as well as F. oxysporum are pathogens with a broad host range that includes garlic (Allium sativum). The losses of garlic due to these pathogens increased over the last years. Especially F. proliferatum was identified several times as the main cause of postharvest dry rot. This species is also known to produce mycotoxins, especially fumonisins. In this study, we aimed to identify and study the phylogeny of the Fusarium species diversity in garlic planting as well as stored material from two cultivars over two seasons. In addition, we surveyed the secondary metabolite production of the isolates obtained from this experimental design as well as in stored garlic intended for consumption. A total of 85 isolates were examined of which 84 % were identified as F. proliferatum. The distribution of the two species was similar for both seasons. In the phylogeny, no influence of season, planting material or stored garlic or cultivar could be detected. In contrast, an influence of the origin of the isolates on the broad spectrum of secondary metabolites could be demonstrated. The isolates showed strong production of fumonisins and other Fusarium metabolites in vitro. 25 % of the commercial garlic bulbs were contaminated with low levels of fumonisin, while 88 % were contaminated with moniliformin. Our results might indicate, that moniliformin plays a role in pathogenesis.