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International Journal of Medicinal Mushrooms

ISSN for PRINT: 1521-9437

Institutional price:	$538.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2005, Volume7

102 pages

DOI: 10.1615/IntJMedMushr.v7.i4

Issue price - $128.00

Physiological and Genetic Variability of Commercial Isolates of Culinary-Medicinal Mushroom Agaricus brasiliensis S. Wasser et al. (Agaricomycetideae) Cultivated in Brazil

Maria A. Neves
Laboratório de Cogumelos Comestiveis e Medicinais, Departamento de Microbiologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil

Maria C. M. Kasuya
Departamento de Microbiologia, BIOAGRO, Universidade Federal de Viçosa, Viçosa, Brazil

Elza F. Araujo
Departamento de Microbiologia, BIOAGRO, Universidade Federal de Viçosa, Viçosa, Brazil

Clarice L. Leite
Departamento de Botânica, Universidade Federal de Santa Catarina, Florianópolis, Brazil

Carla M. Camelini
Laboratório de Cogumelos Comestiveis e Medicinais, Departamento de Microbiologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil

Liz C. C. Ribas
Laboratório de Cogumelos Comestiveis e Medicinais, Departamento de Microbiologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil

Margarida. M. de Mendonca
Departamento de Microbiologia, BIOAGRO, Universidade Federal de Viçosa, Viçosa, Brazil

ABSTRACT

Agaricus brasiliensis S. Wasser et al. ("Cogumelo medicinal"), a culinary—medicinal mushroom native to Brazil, is cultivated mostly for exports. Strain characteristics influence productivity, but little is known about ecological and genetic variation among commercial strains. We examined six strains of A. brasiliensis to determine the characteristics of colony growth and genetic variability. Two colony growth studies were conducted: (1) on ordinary laboratory media, malt extract agar, and potato dextrose agar at several incubation temperatures (20 °, 25 °, 28 °, 30 °C); (2) on minimal media supplemented with glucose) at three pH (6.0,7.0,8.0). We also evaluated linear growth on "race tubes"filled with commercial compost (at 28 °C). Generally, strain 22, commonly considered by producers to have low productivity, tended to grow the slowest on both media at all temperatures, with significant differences in rates found between it and all other strains on both media at 30 °C. At pH 6.0, strain 22 grew more slowly than strains 21, 23, and 24 and presented similar rates to strains 33 and 34. At pH 8.0, no isolate was able to grow. Strain 22 also grew the slowest in race tubes. PCR-RFLPs of the ITS region identified all strains as A. brasiliensis. RAPD patterns identified two groupings: strain 22 and all other strains. Even though we found low genetic variability, important strain characteristics (e.g., low colonization rate) considered related to productivity were detected for strain 22. We conclude that five of the strains may belong to the same ecological/genetic biotype. Low variability among Brazilian commercial strains might suggest a common origin of a single isolate recently brought into cultivation.