Investigating the mechanisms governing host specificity of chytrid fungal parasites of algae

A Short Abstract in Lay Terms Elucidating the molecular mechanisms by which the parasitic chytrid fungus Paraphysoderma sedebokerense infect and collapse algal cultures Application number - 2017283 Sammy Boussiba, Jacob Blaustein Inst. for Desert Research, Ben-Gurion University of the Negev, Israel Timothy James, Department of Ecology and Evolutionary Biology, University of Michigan, USA Algae are a very diverse group of organisms that transform light energy from the sun into the chemical energy of food. As a group, they contribute the majority of primary productivity in aquatic and marine environments. Algal productivity is highly variable in nature, depending mainly on nutrient availability, but also due to attack by parasitic fungi which extract resources for their growth and development. How do parasitic fungi recognize their algal hosts, and what mechanisms lead to successful infection, is the scope of this research. Using a model system we developed, we investigate here a parasitic fungus, Paraphysoderma sedebokerense, which is known to infect the biotechnology important green alga Haematococcus pluvialis, commercially grown for its red antioxidative pigment astaxanthin.

By testing the genes that are expressed once these two organisms meet and as infection develops, we will clarify important means of host specificity of the fungus, mechanisms used by the parasite to penetrate and kill the alga, as well as mechanisms that the algae uses to defense itself.