Phylogenetic analysis of symbiotic Trebouxia 61 microalgae within the genus Parmelia reveal new monophyletic lineages.

Autores UPV
CONGRESO Phylogenetic analysis of symbiotic Trebouxia 61 microalgae within the genus Parmelia reveal new monophyletic lineages.


Parmelia is a genus of medium to large foliose lichens with a cosmopolite distribution. Even though phylogenetic relations within lichen-forming fungi Parmelia have been well established through various studies, little is known about their chlorobiont diversity. Previous studies seem to point to unicellular green algae Trebouxia as the preferred phycobiont within the genus. However, the previously stated lack of molecular and morphological data from these microalgae seems to be a shortcoming within the understanding of the biodiversity and ecological variability of the genus. In this study we aim to provide a new insight into the phylogenetic relationships and the ultrastructural characteristics between the different microalgae found in Parmelia. Selected individuals from both the sorediate Parmelia sulcata Taylor and it¿s close relative P. barrenoae Divakar, M.C. Molina & A. Crespo, and the isidiate lichens Parmelia saxatilis, P. serrana and P. ernstiae were collected across the Spanish forests. Whole lichen DNA extracts were analysed by molecular techniques. Nuclear nrITS and chloroplastic LSU rRNA markers were sequenced from the chlorobionts. These sequences were aligned with type material from different culture banks. Both genes were concatenated afterwards once their evolutionary models were proven to be the same with jModelTest. The widely used fungal barcode nrITS gene was chosen for the mycobionts. Morphological and ultrastructural studies were performed in whole symbiotic thalli as well as in several isolated and cultured micro algae. Phylogenetic analysis reveal what appears to be at least two new Trebouxia lineages present among the analysed microalgae that do not provide a match with any gene sequence available at the GenBank database nor described in any other publication. One clade, not clearly related to any other Trebouxia complex, appears to be an exclusive symbiont of Parmelia sulcata. Our data also suggest another potential new clade of Trebouxia symbolizing with Parmelia serrana, and a third one associated with Parmelia barrenoae thalli which seems to be related to the Trebouxia impressa complex. (MINECO CGL2012-40058-C02-01), FEDER, (PROMETEOII/2013-021 GVA)