Soybean toxin (SBTX), a protein from soybeans that inhibits the life cycle of plant and human pathogenic fungi.
Soybean toxin (SBTX) is a 44 kDa glycoprotein that is lethal to mice (LD(50) = 5.6 mg/kg). This study reports the toxicity of SBTX on pathogenic fungi and yeasts and the mechanism of its action. SBTX inhibited spore germination of Aspergillus niger and Penicillium herguei and was toxic to Candida albicans, Candida parapsilosis, Kluyveromyces marxiannus , Pichia membranifaciens, and Saccharomyces cerevisiae. In addition, SBTX hampered the growth of C. albicans and K. marxiannus and inhibited the glucose-stimulated acidification of the incubation medium by S. cerevisiae, suggesting that SBTX interferes with intracellular proton transport to the external medium. Moreover, SBTX caused cell-wall disruption, condensation/shrinkage of cytosol, pseudohyphae formation, and P. membranifaciens and C. parapsilosis cell death. SBTX is toxic to fungi at concentrations far below the dose lethal to mice and has potential in the design of new antifungal drugs or in the development of transgenic crops resistant to pathogens.
Morais
Janne Keila S
JK
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Campus do Pici, CEP 60451-970 Fortaleza, Ceará, Brazil.
Gomes
Valdirene M
VM
Oliveira
José Tadeu A
JT
Santos
Izabela S
IS
Da Cunha
Maura
M
Oliveira
Hermogenes D
HD
Oliveira
Henrique P
HP
Sousa
Daniele O B
DO
Vasconcelos
Ilka M
IM
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology* / Q000633:toxicity; D001234:Aspergillus niger / Q000187:drug effects / Q000254:growth & development; D002175:Candida / Q000187:drug effects / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D005659:Fungicides, Industrial / Q000494:pharmacology* / Q000633:toxicity; D006023:Glycoproteins / Q000494:pharmacology* / Q000633:toxicity; D006801:Humans; D007716:Kluyveromyces / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D051379:Mice; D010407:Penicillium / Q000187:drug effects; D010843:Pichia / Q000187:drug effects / Q000254:growth & development; D010935:Plant Diseases / Q000382:microbiology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D030262:Soybean Proteins / Q000494:pharmacology* / Q000633:toxicity; D013172:Spores, Fungal / Q000187:drug effects
D000935:Antifungal Agents; D005659:Fungicides, Industrial; D006023:Glycoproteins; C530414:SBTX protein, soybean; D030262:Soybean Proteins