title: Homozygous deletion of ATC1 and NTC1 genes in Candida parapsilosis abolishes trehalase activity and affects cell growth, sugar metabolism, stress resistance, infectivity and biofilm formation.
abstract: A double homozygous atc1Δ/atc1Δ/ntc1Δ/ntc1Δ mutant (atc1Δ/ntc1Δ KO) was constructed in the pathogen opportunistic yeast Candida parapsilosis by disruption of the two chromosomal alleles coding for NTC1 gene (encoding a neutral trehalase) in a Cpatc1Δ/atc1Δ background (atc1Δ KO strain, deficient in acid trehalase). The Cpatc1Δ/ntc1Δ KO mutant failed to counteract the inability of Cpatc1Δ cells to metabolize exogenous trehalose and showed a similar growth pattern on several monosaccharides and disaccharides. However, upon prolonged incubation in either rich medium (YPD) or nutrient-starved medium the viability of Cpatc1Δ cells exhibited a sensitive phenotype, which was augmented by further CpNTC1/NTC1 disruption. Furthermore, Cpatc1Δ/ntc1Δ KO cells had difficulty in resuming active growth in fresh YPD. This homozygous mutant also lacked any in vitro measurable trehalase activity, whether acid or neutral, suggesting that a single gene codes for each enzyme. By contrast, in Cpatc1Δ/ntc1Δ KO strain the resistance to oxidative and heat stress displayed by atc1Δ mutant was suppressed. Cpatc1Δ/ntc1Δ KO cells showed a significant decrease in virulence as well as in the capacity to form biofilms. These results point to a major role for acid trehalase (Atc1p) in the pathobiology of C. parapsilosis, whereas the activity of neutral trehalase can only partially counteract Atc1p deficiency. They also support the use of ATC1 and NTC1 genes as interesting antifungal targets.
authors.affiliation: Área de Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; IMIB-Arrixaca, Spain; Departamento de Microbiología y Ecología, Facultad de Farmacia, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Sánchez-Fresneda
authors.affiliation: Área de Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; IMIB-Arrixaca, Spain.
authors.forename: José P
authors.initials: JP
authors.lastname: Guirao-Abad
authors.affiliation: Departamento de Bioquímica, Biología Molecular (B) e Inmunología, Facultad de Medicina, Universidad de Murcia, 30100 Murcia, Spain; IMIB-Arrixaca, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Martinez-Esparza
authors.affiliation: Departamento de Microbiología y Ecología, Facultad de Biología, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
authors.forename: Sergi
authors.initials: S
authors.lastname: Maicas
authors.affiliation: Departamento de Microbiología y Ecología, Facultad de Farmacia, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
authors.forename: Eulogio
authors.initials: E
authors.lastname: Valentín
authors.affiliation: Área de Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; IMIB-Arrixaca, Spain. Electronic address: arguelle@um.es.
authors.forename: Juan-Carlos
authors.initials: JC
authors.lastname: Argüelles
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002175:Candida / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D050260:Carbohydrate Metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress; D017384:Sequence Deletion; D013312:Stress, Physiological; D014198:Trehalase / Q000235:genetics / Q000378:metabolism*; D014199:Trehalose / Q000378:metabolism; D014774:Virulence
chemical_list: D005656:Fungal Proteins; D014199:Trehalose; D014198:Trehalase
keywords: Antioxidant enzymes; Candida parapsilosis; Gene knockout; Stress resistance; Trehalase; Virulence factor