Diversity, phenomenology and epidemiology of epiphytism in farmed Gracilaria chilensis (Rhodophyta) in northern Chile.

LEONARDI, PATRICIA; MIRAVALLES ALICIA; FAUGERON SYLVAIN; FLORES VERÓNICA; BELTRÁN JESSICA; CORREA JUAN

EUROPEAN JOURNAL OF PHYCOLOGY

British Phycological Society

Lugar: Inglaterra; Año: 2006 vol. 41 p. 247 - 257

0967-0262

This study identified the most common epiphytes infecting the algal host Gracilaria chilensis in a farm of northern Chile.  Simultaneously, the types of host-epiphyte interfaces were characterized and their relative abundance and temporal variability were monitored.  Five types of anatomical relationships were detected.  Infection type I included the epiphytes weakly attached to the surface of the host and not associated with damage of host tissues (i.e. Hincksia mitchelliae, H. granulosa and Ectocarpus acutus).  Infection type II included those epiphytes strongly attached to the surface of the host but not associated with any host tissue damage (i.e. Acrochaetium sp., Antithamnionella sp. and Colpomenia sinuosa).  Infection type III included all the epiphytes that penetrated the outer layer of the host wall without damaging its cortical cells (i.e. Xenococcus sp. and Sahlingia subintegra).  Infection type IV included epiphytes penetrating deep into the host cell wall, disorganising the cortical tissue (i.e. Ulva lactuca and Acrosorium corallinarum).  Infection type V included epiphytes that penetrated deeply into the cortex, reached the medullar tissue and caused destruction of the host’s cells in the area around the infection (i.e. Ceramium rubrum and Polysiphonia harveyi).  Furthermore, this study demonstrated that prevalence varied in time and according to the infection types, with types II and III reaching up to 80% and 90% of the thalli respectively. Incidence of epiphyte infection was similar to the distribution of infection prevalence, with crustose epiphytes colonizing up to 80% of the host surface.