Selection procedure for entomopathogenic fungi using molecular markers

The challenges of mass production and environmental stress affect the application of entomopathogenic fungi (EPF). Therefore, this study attempts to develop a procedure based on EPF molecular markers to facilitate the EP selection.

In this study, three Beauveria bassiana isolates and six Metarhizium spp., were evaluated for conidial production and environmental stress tolerances. The expression levels of six phenotypic related genes were analyzed to assess correlations with conidial production and stress tolerance in two phenotypic different isolates of B. bassiana and Metarhizium spp. In B. bassiana isolates, both slt2 and catA showed strong correlations with conidial production and thermotolerance. Additionally, slt2 and hog1 were associated with osmotic stress tolerance and oxidative stress tolerance, respectively. However, the correlation between phenotypes and gene expression trends was not consistent in Metarhizium spp. Further validation using three M. pinghaense isolates indicated that hog1 was strongly correlated with conidial production, while mbf1, slt2, and cag8 were associated with thermotolerance, oxidative stress tolerance, and osmotic stress tolerance, respectively.

These findings suggest the existence of intraspecies conservation in phenotypic mechanisms and offer a strategy for the rapid selection of promising EPF strains.