Occurrence of Fumonisin B 1 and B 2 in Fusarium proliferatum Infected Asparagus Plants Antonio Logrieco,* ,² Bruno Doko, ² Antonio Moretti, ² Salvatore Frisullo, ‡ and Angelo Visconti ² Istituto Tossine e Micotossine da Parassiti Vegetali, CNR, 70125 Bari, Italy, and Istituto di Produzione e Preparazione Alimentare, Universita` degli Studi di Bari, 71100 Foggia, Italy Fusarium proliferatum, a fumonisin producing fungal species, is a causal agent of a destructive disease of asparagus called Fusarium crown and root rot. The occurrence of fumonisin B 1 (FB 1 ) and B 2 (FB 2 ) in asparagus plants heavily infected by F. proliferatum has been investigated together with the capability of producing FB 1 and FB 2 by the fungus. Both fumonisins were detected in asparagus plants colonized by F. proliferatum at levels of 7.4 and 0.83 μg/g (FB 1 ) and 0.46 μg/g and 0.06 μg/g (FB 2 ) in crown and stem samples, respectively. Eight out of nine isolates of F. proliferatum tested for sexual compatibility proved to be members of Gibberella fujikuroi mating population D. All nine isolates produced high amounts of FB 1 and FB 2 (up to 2504 and 946 μg/g, respectively) when cultured on autoclaved maize kernels for 4 weeks at 25 °C. This is the first report of the natural occurrence of fumonisins in asparagus plants. Keywords: Fumonisins; Fusarium proliferatum; Liseola section; toxins; asparagus INTRODUCTION Fusarium proliferatum (Matsushima) Nirenberg, a member of the Liseola Woll section, is considered a severe pathogen of various economically important plants, including asparagus (Asparagus officinalis L.). It can be colonizer of both vascular and epidermal asparagus tissues (La Mondia and Elmer, 1989) and cause crown and root rot, alone or together with F. oxysporum f. sp. asparagi (Damicone and Manning, 1985; Elmer, 1991; Schreuder et al., 1995). Despite the importance as pathogen of asparagus, limited informa- tion exist on the capability of producing toxins by F. proliferatum isolated from this host. Fusarium proliferatum is a toxigenic species (Marasas et al., 1984) and various strains of the species, mostly isolated from maize plants, were reported as capable of producing several toxins, including fumonisin B 1 (FB 1 ) and B 2 (FB 2 ) (Ross et al., 1990; Nelson et al., 1992; Visconti and Doko, 1994). Although fumonisins were first studied as mycotoxins with cancer-promoting activ- ity (Gelderblom et al., 1988), recently the toxic activities of fumonisins have been also shown in plant systems (Lamprecht et al., 1994) hyphostatizing their important role in the disease. To date, the production of FB 1 by F. proliferatum has been mainly shown for isolates from maize (Ross et al., 1990; Visconti and Doko, 1994; Chulze et al., 1996), wheat, sorghum (Leslie et al., 1992), and rice (Desjardins et al., 1997), and fumonisins have been detected in infected maize plant as a natural contaminant (Sydenham et al., 1990; Logrieco et al., 1995; Chulze et al., 1996). Isolates of F. proliferatum can sexually cross to produce perithecia of Gibberella fujikuroi (Sawada) Ito in Ito & K. Kimura mating population D (Leslie, 1991), which proved to be highly pathogenic toward asparagus (Elmer and Ferrandino, 1992). Recently, Elmer (1995) studied a large number of isolates of Fusarium Liseola section from asparagus in the United States and con- firmed the predominance of the mating population D of G. fujikuroi. In the course of a large investigation on the most occurring Fusarium species causing stem and crown rot of asparagus plants from all around Italy, we focused our attention on a single field of southern Italy (Potenza) for the fumonisin occurrence in infected asparagus plants. Strains of F. proliferatum isolated from infected tissues were also studied for their capability to produce FB 1 and FB 2 as well as for sexual compatibility. MATERIALS AND METHODS Twenty-five asparagus plants affected by crown rot were randomly collected from a field of an asparagus producing area of southern Italy (Potenza). Internal crown and stem tissues of each plant were surface-disinfected for 1 min in 3% NaOCl. After rinsing twice with sterile water, the tissues were placed on plates (three pieces per plate) containing a modified pentachloronitrobenzene medium selective for Fusarium (Nash and Snyder, 1962; Nelson et al., 1983) and incubated in the dark at 25 °C for 1 week. Fusarium colonies were transferred to potato-dextrose agar (PDA) and carnation leaf agar (Nelson et al., 1983) plates and incubated at 25 °C for 10 days under fluorescent and black-light lamps (2700 lux) with a 12-h photoperiod. The identification of the Fusarium species was made according to the taxonomic system of Nelson et al. (1983). Nine single-conidial strains of F. proliferatum isolated from these plants were used for fertility and toxin production studies and then deposited in the culture collection of the Istituto Tossine e Micotossine da Parassiti Vegetali (ITEM), Bari, Italy. Cross Condition. Tester strains of the six G. fujikuroi mating population (A, B, C, D, E, and F) were used to make crosses with the isolates from asparagus using carrot agar medium as reported by Klittich and Leslie (1988). All strains * Author to whom correspondence should be addressed (telephone +39 80 5481570; fax +39 80 548 6063; e-mail a.logrieco@area.ba.cnr.it). ² Istituto Tossine e Micotossine da Parassiti Vegetali. ‡ Universita` degli Studi di Bari. 5201 J. Agric. Food Chem. 1998, 46, 5201-5204 10.1021/jf9804903 CCC: $15.00 © 1998 American Chemical Society Published on Web 11/20/1998