title: Pseudocercospora griseola causing angular leaf spot on Phaseolus vulgaris produces 1,8-dihydroxynaphthalene-melanin.
abstract: Pseudocercospora griseola is the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two major groups have been defined, "Andean" (P. griseola f. griseola) and "Mesoamerican" (P. griseola f. mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of each group. After 21 days of incubation on potato dextrose agar medium, P. griseola f. griseola isolate S3b developed colonies with diameters of 17.5 +/- 1.3 mm and concentric rings of pigmentation. Isolate T4 of P. griseola f. mesoamericana presented smaller colonies (9.9 +/- 0.3 mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment, a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum. The P. griseola f. griseola isolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared to the isolate T4 of P. griseola f. mesoamericana. These results suggest a possible link between melanin and growth in P. griseola.
authors.affiliation: Instituto de Fisiología Vegetal (INFIVE), Universidad Nacional de La Plata (UNLP)-CCT-La Plata-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Diag. 113 y 61, CC 327, 1900 La Plata, Argentina. masaparrat@yahoo.com.ar
authors.forename: Mario C N
authors.initials: MC
authors.lastname: Saparrat
authors.forename: Geraldine E
authors.initials: GE
authors.lastname: Fermoselle
authors.forename: Sebastián A
authors.initials: SA
authors.lastname: Stenglein
authors.forename: Mónica B
authors.initials: MB
authors.lastname: Aulicino
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Balatti
mesh_terms: D001203:Ascomycota / Q000302:isolation & purification* / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D008543:Melanins / Q000096:biosynthesis*; D009284:Naphthols; D027805:Phaseolus / Q000382:microbiology*; D010860:Pigments, Biological / Q000096:biosynthesis; D010935:Plant Diseases / Q000382:microbiology*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: C423455:1,8-dihydroxynaphthalene melanin; D003470:Culture Media; D008543:Melanins; D009284:Naphthols; D010860:Pigments, Biological