Toxigenic profile ofAlternaria alternataandAlternaria radicinaoccurring on umbelliferous plants

Abstract

Alternaria alternata and Alternaria radicina are fungal species that occur in several food crops and may produce mycotoxins and phytotoxins. The toxigenic profile of A. alternata and A. radicina isolated from carrot and other umbelliferous plants was determined by growing the fungus on rice and carrot discs. Most of the tested isolates of A. alternata produced the mycotoxins tenuazonic acid, alternariol, alternariol methyl ether and altertoxin-I on rice. Only alternariol and alternariol methyl ether were produced on carrot discs. When cultured on rice, none of the isolates of A. alternata from umbelliferous plants produced AAL toxins and fumonisins. AAL toxins, but not fumonisins, were instead produced by A. alternata f. sp. lycopersici isolate NRRL 18822 isolated from tomato. A. radicina produced the phytotoxic compounds radicinin, epi-radicinol and radicinol on carrot discs, whereas it produced radicinin and radicinol on rice. Although A. alternata has been frequently found in organic carrots, none of the above mycotoxins was detected in carrot roots or in carrot commercial products. The reduction of alternariol and alternariol methyl ether during carrot juice processing at laboratory scale was estimated to be >98%. Based on these findings and previous reports, it can be concluded that Alternaria mycotoxins in carrots do not represent a hazard for consumers.

PCR detection and identification of Alternaria species-groups in processed foods based on the genetic marker Alt a 1

“…Phylogenetic studies support grouping Alternaria species in several species-groups (Chou & Wu, 2002;Hong et al, 2005): 1) A. alternata species-group includes species like A. alternata, Alternaria arborescens, A. tenuissima, A. gaisen, A. citri, and A. longipes. They produce mycotoxins like alternariol (AOH), alternariol methyl ether (AME) and tenuazonic acid (TeA) (Andersen, Kroger, & Roberts, 2001 and are responsible for extensive deterioration of plants and plant products, leading to considerable economic losses to growers and the food processing industry; 2) A. porri species-group includes species like A. solani, A. porri, Alternaria dauci, and A. tomatophila, that are responsible of foliar blights of carrots, onions, potatoes, and tomatoes and produce mycotoxins as AOH, altertoxins and altersolanol (Andersen, Dongo, & Pryor, 2008); 3) Alternaria radicina species-group is considered one of the most important seed-borne pathogen on carrot and produce phytotoxic compounds as radicinin and radicinol (Konstantinova, Bonants, van Gent-Pelzer, van der Zouwen, & van den Bula, 2002;Solfrizzo et al, 2005;Tylkowska, 1992); and 4) Alternaria infectoria species-group affects cereal crops in the field and during storage, and produce metabolites like infectopyrones and novae-zelandins that are not found in other Alternaria species-groups (Andersen, Sorensen, Nielsen, van den Ende, & de Hoog, 2009;Christensen et al, 2005).…”

Evaluation of non-chemical seed treatment methods for the control of Alternaria dauci and A. radicina on carrot seeds

“…A. radicina has also been reported to cause foliar blight on parsley, stalk/root rot of celery, and to be pathogenic on caraway, dill, fennel and parsnip (Farrar et al 2004). A. radicina is a producer of mycotoxins that adversely affect the germination of carrot seeds (Tylkowska et al 2003) but apparently do not present a hazard for consumers (Solfrizzo et al 2005). In most carrot production areas, chemical control of Alternaria leaf blight is practised to prevent destruction of the photosynthetic surface area of the plant and to allow for efficient mechanical harvest (Ben-Noon et al 2003;Bounds et al 2007).…”

Response of carrot protoplasts and protoplast-derived aggregates to selection using a fungal culture filtrate of Alternaria radicina

“…Radicinin, radicinol, and epi-radicinol are the main phytotoxins involved in the pathogenicity of A. radicina against carrots (Solfrizzo et al 2004). These were identified in naturally infected carrot roots, but also produced in vitro on carrot discs or in liquid potato-dextrose medium after inoculation with A. radicina mycelium (Shakir 1999;Solfrizzo et al 2004Solfrizzo et al , 2005. Higher levels of these phytotoxins were observed in carrot cultivars more susceptible to A. radicina (Solfrizzo et al 2004).…”