Chemotaxis of zoospores of <i>Aurantiochytrium limacinum</i> SR21

Chemotactic responses of Aurantiochytrium limacinum SR21 to 90 distinct compounds including sugars, organic acids, alcohols, amino acids, amines, aromatic compounds, sulfoxides, vitamins, nucleosides, and inorganic compounds were analyzed. While the zoospores were significantly attracted to several amino acids, they did not respond to their typical nutrients such as sugars or organic acids, suggesting that the chemotaxis may not be directly involved in the search for their nutrition. Zoospores were also attracted to vanillin, which is a component of lignin and a major component of land plant cell walls. This suggests that Aurantiochytrium sp. may be involved in the cycling of carbons in terrestrial plant biomass between land and sea via lignin. Structural comparisons of responding and nonresponding vanilloids indicated that the hydrocarbon chain at position 1, the alkoxyl group at position 3, and the hydroxyl group at position 4 may be particularly important in vanilloid recognition.