Genetic variation in Symbiodinium (= Gymnodinium) microadriaticum Freudenthal, and specificity in its symbiosis with marine invertebrates. III. Specificity and inlfectivity of Symbiodinium microadriaticum

Abstract

Nine of 12 tested strains of the zooxanthella Symbiodinium (= Gymnodinium) microadriaticum can initiate symbiotic associations with an aposymbiotic clone of the sea anemone Aiptasia tagetes. The growth of each strain during the 1st 2 mo. of association is generally related to the isoenzyme similarity coefficient of the strain relative to strain A, the strain originally isolated from A. tagetes. The growth of heterologous algae in Aiptasia is not enhanced by previous association with A. tagetes. An hypothesis on the nature of specificity, which involves a recognition mechanism between algae and potential host and competition between endosymbiont strains within hosts, is presented.