INMIBO ( EX - PROPLAME)   14614
INSTITUTO DE MICOLOGIA Y BOTANICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Secondary metabolite profiles as a tool for Alternaria species characterization
Autor/es:
BENAVIDES, MARTHA E.; PATRIARCA, A.; CABRERA, G.; FERNÁNDEZ PINTO, V.
Lugar:
Mendoza
Reunión:
Conferencia; MycoRed ISM conference; 2011
Institución organizadora:
International Society for Mycotoxicology
Resumen:
The morphological classification of small- spored Alternaria has been discussed for more than 25 years. Studies based on molecular phylogenetic relations have clustered them into distinct species clades which are not correlated with species groups based on morphological characteristics. These species are involved in the pathology of diseases related to host ? specific toxin production and have in common the production of some metabolites as the alternariols and are probably highly related. The analysis of secondary metabolite profiles (chemotaxonomy), of which host specific toxins are part, has shown high value in the classification and differentiation of many fungal species but even though a large number of secondary metabolites are known from plant pathogenic Alternaria, few studies have investigated metabolite production for classification and identification. The objective of this work was to compare metabolite profiles and currently accepted classification according to sporulation patterns to suggest species specific metabolites that could be chemotoxonomic markers for the differentiation and characterization of small- spored Alternaria (A. alternata, A. tenuissima and A. arborescens). Fifty one Alternaria strains isolated from moldy tomatoes were identified according to conidia morphology and sporulation patterns (Simmons 2007). The reference A. alternata EGS 34-016, A. tenuissima EGS 34-015 and A. arborescens EGS 38 128 were included. Isolates were inoculated onto 7 media: MEA, DRYES, YES, OA, NS, PSA and Tomato Agar. Two plugs of each media were extracted with chloroform-methanol (2:1), ethyl- acetate ? formic acid (99:1) and 2-propanol successively. The extracts were combined and analyzed by HPLC ?MS. The MS spectra were done with a high precision dual source ESI- APCI. Sixteen strains were morphologically identified as A. alternata, 28 as A. tenuissima and 4 as A. arborescens. From the A. alternata strains 17/19 (89%) produced Alternariol (AOH), 18/19 (95%) Alternariol methyl ether (AME), 13/19 (68%) Tenuazonic Acid (TZ), 8/19 (42%) Tentoxin (TX) and 4/19 (21%) Altenuene (ALT). Regarding the A. tenuíssima strains 25/28 (89%) produced AOH, 26/28 (93%) produced AME, 18/28 (64%) produced TZ, 4(14%) produced TX and 5/28 (18%) produced ALT. One of the A. arborescens strains didn?t produce any mycotoxin, one produced AAL toxins TA and TD, one produce only TZ and the other produce AOH, AME and TX. According to these results A. alternata and A. tenuísima have shown a similar pattern on AOH, AME, TZ and ALT production, but there is a remarkable difference that must be more investigated in the TX production as it could be used as chemotaxonomic marker in A. alternata strains. A. arborecens strains showed a diverse pattern of metabolite production, but this species could also be clustered with molecular markers.  The sporulation patterns combined with metabolite profiles could be a powerful tool for A. alternata and A. tenuissima characterization.