ABSTRACT
One fascinating recent discovery in phycology is that bacteria are essential for the growth, development, and morphogenesis of macroalgae. Axenic cultures, which can be easily achieved for the green marine macroalga Ulva mutabilis (Chlorophyta), are an important prerequisite for the study of bacteria–algae interactions. The protocol describes a robust approach to purify gametes from their accompanying bacteria on the basis of the strong phototaxis of the gametes. Axenic cultures also pave the way to design feedstocks with defined microbiomes for algal aquacultures. The protocol includes the reliable determination of the gamete density using flow cytometry. Owing to these defined culture conditions, Ulva evolves into a model organism, bacteria-induced growth, and morphogenesis.
Keywords: Axenic culture, gametes, gametogenesis, macroalga, flow cytometry, Ulva
