Phenotypic effects in Saccharomyces cerevisiae after regulated expression of beta-(1,3)-glucanase from Nicotiana plumbaginifolia.

A recombinant yeast strain was constructed of which the cell wall porosity could be reversibly and conditionally modulated. This strain expresses the Nicotiana plumbaginifolia beta-(1,3)-glucanase under control of the Saccharomyces cerevisiae GAL1 promoter and the mating factor alpha 1 prepro-sequence. The following phenotypic effects were observed after expression of this enzyme: (a) expressed beta-(1,3)-glucanase is toxic to the producing yeast cells, which is reflected by a strong growth inhibition; as beta-(1,3)-glucanase could be detected only inside the cells, it seems to interfere with cell wall growth from within the cell; (b) after induction of glucanase, the recombinant strain lost up to 20% of some periplasmic enzymes, as evidenced by the release of normally periplasmic-associated invertase; (c) preliminary growth in a synthetic medium containing galactose significantly increased the transformation efficiency of the recombinant yeast strain.