Soybean toxin (SBTX) impairs fungal growth by interfering with molecular transport, carbohydrate/amino acid metabolism and drug/stress responses

ABSTRACT: Soybean toxin (SBTX) is an antifungal protein from soybeans with broad growth and filamentation inhibitory activity against many fungi, including human and plant pathogenic species such as Candida albicans, Candida parapsilosis, Aspergillus niger, Penicillium herquei, Cercospora sojina, and Cerospora kikuchii. Understanding the mechanism by which SBTX acts on fungi and yeasts may contribute towards the design of novel antifungal drugs and/or for the development of transgenic plants resistant to pathogens. To gain new insights into the mode of action of SBTX, the polymorphic yeast C. albicans was chosen as a model organism, and changes in the gene expression profile of strain SC5314 upon exposure to SBTX were examined. Genes that were differentially regulated in the presence of SBTX were involved in glucose transport and starvation-associated stress responses, as well as in the control of both the induction and repression of C. albicans hyphal formation. Transmission electron microscopy showd that C. albicans cells exposed to SBTX displayed severe signs of starvation and were heavily granulated. Our data were indicative of C. albicans cells starving despite sufficient nutrient availability in the medium, and it can therefore be speculated that SBTX blocks nutrient uptake systems. Because neither the starvation signal nor the alkaline response pathway lead to the induction of hyphae, we hypothesise that conflicting signals are transmitted to the complex regulatory network controlling morphogenesis, eventually preventing the filamentation signal from reaching a significant threshold. For transcriptional profiling, the cells were growth in the presence or absence of SBTX (200 M-BM-5gM-bM-^HM-^YmL-1) in SDB/4.The cultures were grown until they reached an OD600 of approximately 0.5, after 16 and 18 h, for untreated and SBTX-treated cells. The cells were harvested by centrifugation (3000M-bM-^@M-"g at 25M-BM-0C), snap-frozen in liquid nitrogen and stored at -80M-BM-0C. Each pair of samples (untreated and SBTX-treated cells) constituted a single experiment, and two biologically independent experiments were carried out.

ORGANISM(S): Candida albicans

SUBMITTER: Lennart Opitz 

PROVIDER: E-GEOD-47364 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress