Diversity of Ca2+-induced morphology revealed by morphological phenotyping of Ca2+-sensitive mutants of Saccharomyces cerevisiae.

Yeast cell morphology can be treated as a quantitative trait using the image processing software CalMorph. In the present study, we investigated Ca(2+)-induced morphological changes in Ca(2+)-sensitive (cls) mutants of Saccharomyces cerevisiae, based on the discovery that the characteristic Ca(2+)-induced morphological changes in the Ca(2+)-sensitive mutant zds1 reflect changes in the Ca(2+) signaling-mediated cell cycle control pathway. By applying hierarchical cluster analysis to the quantitative morphological data of 58 cls mutants, 31 of these mutants were classified into seven classes based on morphological similarities. The patterns of morphological change induced by Ca(2+) in one class differed from those of another class. Based on the results obtained using versatile methods for phenotypic analysis, we conclude that a high concentration of Ca(2+) exerts a wide variety of effects on yeast and that there are multiple Ca(2+)-regulatory pathways that are distinct from the Zds1p-related pathway.