Assessment of the phytopathogen Cladosporium cladosporioides inhibition by Meyerozyma guilliermondii LMA-Cp01 using isothermal microcalorimetry.

Abstract

Traditional microbiological methods to assess the antagonistic effect of yeasts in controlling phytopathogen fungi are often slow and based on subjective growth measurements. Therefore, isothermal microcalorimetry (IMC) is proposed as a novel, sensitive, and accurate technique that measures the heat released during the metabolic processes of microorganisms. For this reason, this study aimed to evaluate the antagonistic effect of Meyerozyma guilliermondii LMA-Cp01 on Cladosporium cladosporioides, using the mycelial growth diameter technique and IMC. The thermokinetic parameters issued from the thermogenic and thermogenic integrated curves, such as maximum growth rate, lag phase, total produced heat, and time to peak, showed variations as a function of the yeast concentration used. The deconvolution of the thermogenic curves, using the asymmetric double sigmoidal function (Asym2sig) model, allowed independent estimation of the growth of C. cladosporioides and M. guilliermondii. Pearson correlation coefficients were calculated to better understand the relationship between the two techniques. The correlations showed that the total heat of the fungal deconvoluted curves has a high correlation (larger than -0.98) with the in vitro inhibition percentage. Therefore, this study supports using IMC as an alternative to complement classical methods of fungal inhibition using yeast.