Ethylacetate extract of the gorgonian coral Suberogorgia reticulata was obtained and its effects on the larval settlement by acorn barnacle Balanus (=Amphibalanus) reticulatus and pearl oyster Pinctada martensii and spore germination of green algae Ulva linza and U. lactuca and red alga Gracilaria tenuistipitata was assessed in this study. Results showed that no larval settlement or spore germination occurred at the dose of 100 μg cm−2. Both larval settlement and spore germination were significantly inhibited by the extract at doses of 1 μg cm−2 for B. reticulatus, 0.1 μg cm−2 for U. linza and U. lactuca, and 0.01 μg cm−2 for P. martensii and G. tenuistipitata. It could be concluded that the gorgonian coral S. reticulata may produce bioactive substances with a broad spectrum of activity against a range of marine sessile organisms including macroalgae and invertebrates.

Genomic DNA from spores of the endomycorrhizal fungus Gigaspora margarita was amplified with two sets of degenerate primers designed on conserved regions of chitin synthase polypeptides. Three chitin synthase (chs) gene portions were identified: Gimchs1, Gimchs2 and Gimchs3, encoding one class II and two class IV chitin synthases, respectively. Gimchs1 and Gimchs3 transcripts were detected by reverse transcription polymerase chain reaction (RT-PCR) during root colonization, whereas none of three mRNAs was revealed during spore germination. The potential role of the genes expressed is discussed in the light of morphogenetic and signalling events.