An introductory study on a foliicolous lichen found on common trees in kerala, india: characterization of its symbiotic partners

Lichens are composite living organisms formed by the symbiotic relationship between the photobiont and the mycobiont. Foliicolous or epiphyllous lichens are those that grow on the leaves of vascular plants. In the present study we investigated the formation and reproduction of a Phyllophiale like foliicolous lichen which inhabited the leaves of almost all common trees in Kerala, India, especially Mangifera indica, Ixora coccinea, Mesua ferrea, Syzygium cumini and Garcinia mangostana. Morphological examination of the lichen peels revealed Phycopeltis as the major photobiont. Trebouxia cells were also found to be associating with the lichen. The study showed the presence of a fungal associate in all the collected lichen samples. We could culture the fungus in vitro. DNA barcoding using primers of ITS showed that fungal associate may be a member of Botryosphaeriaceae. In vitro culture of lichen seemed to produce many structures which were not observed during their natural development. The study also attempted to investigate the effect of the foliicolous lichen on the rate of photosynthesis of the host plant and found that that the presence of the lichen on the leaf surface has no retarding effect on the rate of photosynthesis.