The toxicity of jack bean [Canavalia ensiformis (L.) DC.] canatoxin to plant pathogenic fungi

Abstract

Protein fractions obtained from seeds of the jack bean (Canavalia ensiformis) as well as the amino acid canavanine, present in these seeds, were tested for their capacity to inhibit the growth of the phytopathogenic fungi Macrophomina phaseolina, Colletotrichum gloesporioides, Sclerotium rolfsii and Fusarium oxysporum. We found that most of the proteins examined and also canavanine did not have any effect on the growth of these fungi. On the other hand the toxic protein canatoxin was found to be effective, at a concentration of 2%, in the inhibition of the growth of M. phaseolina, C. gloesporioides and S. rolfsii.Key words: Canavalia ensiformis, jack bean seeds, canatoxin, phytopathogenic fungi. RESUMO

Ureases: Historical aspects, catalytic, and non-catalytic properties – A review

“…Ureases are toxic against filamentous fungi and yeasts [183] . The fungitoxic activity of CNTX was the first reported showing that the protein at 2% concentration caused growth inhibition of the phytopathogenic filamentous fungi Macrophomina phaseolina, Colletotrichum gloesporioides and Sclerotium rolfsii [184] . Becker-Ritt et al, 2007, reported that JBU and the soybean embryo-specific ureases inhibited growth and/or spore germination of seven other species of filamentous fungi at sub-micromolar concentrations and caused damage to cell wall, even after blockage of their ureolytic active sites.…”

Soybean Urease: Over a Hundred Years of Knowledge

“…Table 2 summarizes some of these overlooked biological activities of plant ureases. The main discoveries were made for the jackbean ureases (CNTX and JBU), revealing several interesting properties, such as entomotoxicity [74][75][76][77], fungitoxicity [78,79] and secretory activity [5,80].…”

Análise química em órgãos de reserva de algumas herbáceas e arbóreas ocorrentes na flora do Espírito Santo, Brasil

“…Uma das propriedades desse composto está relacionado aos mecanismos de defesa das plantas. Canavalia ensiformes possui diversos metabólitos antinutricionais como a lectina, canavalina A, uréases, inibidores de proteases e canatoxina que em conjugação com os galactomananos têm efeito tóxico no desenvolvimento das larvas de insetos (Oliveira et al 1999a;b). A ausência de sementes com sinais de herbivoria (dados não mostrados) em C. rosea pode indicar a presença de compostos antinutricionais com função antiherbivoria como constatado em Canavalia ensiformes (Oliveira et al 1999a;b) e em outras espécies do Gênero Canavalia (Sridhar & Seena 2006).…”