“Pseudocercospora griseola (Fungi Imperfecti) produces 1,8-dihydroxynaphthalene-melanin”.

SAPARRAT M. C. N.; FERMOSELLE, G. E.; AULICINO, M. B.; BALATTI, P. A.

Mar del Plata

Congreso; “VI Congreso Latinoamericano de Micología”.; 2008

Sociedad Latinoamricana de Micología

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} span.estilo1 {mso-style-name:estilo1; font-family:"Times New Roman"; mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"; mso-bidi-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&ampPseudocercospora griseola, the causative agent of angular leaf spot, a disease of common bean (Phaseolus vulgaris), has undergone parallel micro-evolution with its host and two major gene pools have been defined, “Middle American” (P. griseola f. griseola) and “Andean” (P. griseola f. mesoamericana). The objective of this study was to analyze physico-chemical characteristics and production level of the dark pigment produced by fungal isolates, representatives of each gene pool, cultured on solid and liquid media. While on potato-dextrose-agar medium P. griseola f. griseola isolate S3b showed a zonation in pigmentation, isolate T4 of P. griseola f. mesoamericana presented colonies of a uniform and intense dark-gray color. Nevertheless, both isolates Sb3 and T4 produced a 1,8-dihydroxynaphthalene-melanin, whose quantity and IR-spectra were different in the Andean and Middle American gene pool. The P. griseola f. griseola isolate S3b had a higher growth rate, melanin and its chromophore group content as well as sensitivity to melanin-inhibitors compared to the isolate T4 of P. griseola f. mesoamericana. These results suggest that melanin might play a role in this phytopathogen growth in-vitro.