Potential of the mushrooms Lentinula edodes (shiitake) and Agaricus blazei (royal mushroom) in the control of diseases in cucumber, passion fruit and tomato plants, and the partial purification of biologically active compounds.

Author(s)

Robson Marcelo Di Piero

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2003-09-08

Examining board members

Sergio Florentino Pascholati; Marcia Regina Braga; Augusto Ferreira da Eira; Jorge Alberto Marques Rezende

• Advisor: Sergio Florentino Pascholati

Abstract

The mushrooms Lentinula edodes and Agaricus blazei have substances in the fruiting body and in the mycelia exhibiting antibiotic activity and others able to stimulate the immune system in animals. There are many reports about the performance of these substances in the control of animal diseases. In vegetables, there are no information about the protecting effect of the royal mushroom against plant pathogens. In the case of shiitake, although few in number, the studies showed the potential of the mushroom for the control of plant diseases, such as tomato bacterial wilt, sorghum leave spots and bacterial disease of the passion fruit plant. The objectives of the present work were to evaluate the effect of different preparations from L. edodes and A. blazei to control the diseases cucumber anthracnose, tomato bacterial spot and passion fruit woodiness. As the protection of the plants was obtained, the studies tried to elucidate the way of action of the preparations, as well as partially purify them, in an attempt to concentrate the active compound. In cucumber plants, fruiting body aqueous extracts, from different mushroom isolates, reduced anthracnose severity, depending upon the extract concentration. The extracts did not affect adversely the disease causal agent, Colletotrichum lagenarium, but induced the peroxidase and quitinase accumulation in the treated leaves and systemically. By using fractional precipitation of the shiitake fruiting body aqueous extracts with ammonium sulfate, and anion exchange chromatography, a protein fraction exhibiting molecular mass around 29 to 35 kDa and peroxidase elicitor activity in cucumber cotyledons was obtained. In tomato plants, the isolate ABL 99/28 of A. blazei was the one that, on average, gave higher protection against Xanthomonas vesicatoria, which was dependent upon the extract and bacterial cell concentrations. Again, the fruiting body aqueous extract of ABL 99/28 did not act directly onto the pathogen, but it caused an increase in b-1,3-glucanase activity in the treated leaves, suggesting that the mushroom action in cucumber and tomato plants involved the induced resistance. On the other hand, the fruiting body extracts, obtained from different isolates of both mushrooms, protected locally passion fruit plants inoculated mechanically with the Passion fruit woodiness virus (PWV) by reducing viral infectivity, what was proven through tests carried out with Chenopodium quinoa, a PWV local lesion host. However, there was no systemic protection in passion fruit plants against the virus in the experiments involving mechanical inoculation, reducing the possibilities of the mushroom use for the PWV control in the field. In a general way, the results showed that the mushrooms L. edodes and A. blazei have substances that activate the plant defense mechanisms and they show some potential in the control of vegetable diseases, depending upon the nature of the pathogen. (AU)