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Á. PÉREZ CABO y C. GARCÍA MENDOZA AN. R. ACAD. NAC. FARM.

RESUMEN

Mecanismo común de reconocimiento y unión de las moléculas
complementarias, carbohidrato-lectina, en la verticiliosis de las setas

cultivadas Agaricus bisporus y Pleurotus ostreatus

Se compara la interacción carbohidrato-lectina entre el glucogalactomanano
aislado de las paredes celulares de Verticillium fungicola y las lectinas de los car-
póforos de Agaricus bisporus o de Pleurotus ostreatus, para establecer el mecanis-
mo molecular de la «mole seca» o verticiliosis de los cultivos comerciales de ambas
setas comestibles. La interacción entre las moléculas complementarias, «moléculas
diana», parece ser debida a la galactosa terminal unida en (1-4) al esqueleto de
manosa unido en (1-6) de la molécula del glucogalactomanano de V. fungicola.

Palabras clave: «Mole seca».—Verticiliosis.—Glucogalactomanano de Vertici-
llium fungicola.—Lectina de Agaricus bisporus.—Lectina de Pleurotus ostreatus.

INTRODUCTION

Verticillium fungicola (Preuss) Hassebrauk var. fungicola is a
mycoparasite that causes dry bubbles, stipe blow-out and necrotic
lesions («dry bubble» or verticillium disease) in the commercial
cultures of white button mushroom Agaricus bisporus (Lange) Imbach
(1, 2), the losses in the yield having been estimated at several hundred
million dollars. Control of the disease has been partially achieved by
the use of fungicides as well as cultural and sanitary practices, but
resistance to the most effective chemical (prochloraz) is increasing (3).
Therefore, to develop alternative strategies for its control, it has
been necessary to elucidate the nature of the interaction between
the mycoparasite and its host. Recently studies carried out in
this laboratory have demonstrated by different approaches:
i) agglutination of V. fungicola germinated spores by an A. bisporus
extract from fruit body cell walls; ii) inmunofluorescence microscopy
of A. bisporus hyphae from fruit bodies and vegetative mycelia
pretreated with purified V. fungicola cell wall glucogalactomannan (4),
and iii) by hemagglutination experiments carried out with an A.
bisporus fruit body glycoprotein lectin in the presence and absence of
the same V. fungicola glucogalactomannan, that a specific recognition
step is involved in this mycosis (5) before the development of the
external symptoms of the disease. This mechanism of specific

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