A stress-induced "mycosome" phase of Aureobasidium pullulans consisting of minute reproductive propagules that may. revert directly to walled yeast cells is described. Mycosomes detected by light- and electron-microscopy reproduce within senescent plant plastids, and display three developmental pathways: wall-less cells (protoplasts). yeast cells, or membrane-bounded spherules that harbor plastids. Widespread in plant and algal cells. mycosomes are produced by both ascomycete and basidiomycete fungi
