Temperature regulation of nuclear division in apomictic yeast

Abstract

The effect of temperature on nuclear division and spore formation in an apomictic, two-spored strain of Saccharomyces cerevisiae (19e1) was investigated. Presporulation culture at 36 °C increased markedly the frequency of asci containing three or four spores that developed in sporulation medium, indicating a morphogenic role for temperature in control of meiosis in apomictic yeast. Mild temperature shock treatments administered to cells shortly after transfer from presporulation to sporulation medium also promoted nuclear division and three classes of asci developed: binucleate, trinucleate, and tetranucleate. Nuclear divisions were not always completed before the onset of spore formation in trinucleate asci.