Myrmecia israeliensis as the primary symbiotic microalga in squamulose lichens growing in European and Canary Island terricolous communities

Abstract

Abstract:Myrmecia israeliensis has been traditionally considered as a green coccoid free-living microalga. This microalga was previously suggested as the primary phycobiont in the lichens Placidium spp., Heteroplacidium spp., and Psora decipiens. However, due to the absence of ITS rDNA sequences (barcode information) published along with these investigations, the symbiotic nature of M. israeliensis might be confirmed by using the DNA barcoding and different microscopic examinations both in the symbiotic state and in culture. The aim of this study was to settle the presence of M. israeliensis as the primary microalga in squamulose lichens growing in terricolous communities (Psora spp., Placidium spp. and Claviscidium spp.) in 32 localities within European and Canary Island ecosystems by using both molecular and ultrastructural techniques. The lichen-forming fungi were identified using ITS rDNA as a barcode, and in the case of P. decipiens specimens, the mycobiont analyses showed an unexpected variability. Phycobiont phylogenetic analyses were made using both chloroplast (LSU rDNA) and nuclear (ITS rDNA) molecular markers. Our results proved that M. israeliensis is the primary symbiotic microalga in all the chosen and analyzed lichens. In addition, fluorescence microscopy, transmission electron microscopy and scanning electron techniques were used to characterize M. israeliensis. Finally, the presence of this microalga in lichen thalli was verified using different microscopic observations. A combination of different techniques, both molecular and microscopic, allowed for the accurate identification of this symbiotic microalga, beforehand mainly known as free living. Here, we suggest the combination of these techniques to prevent incorrect identification in microalgal lichen studies.

Symbiotic microalgal diversity within lichenicolous lichens and crustose hosts on Iberian Peninsula gypsum biocrusts

“…This work is complementary to that of Moya et al 49 , 50 , where microalgal diversity was analysed in foliose and dimorphic Cladonia spp . and in squamulose Psora decipiens , P. saviczii , Clavascidium spp.…”

“…developed on the same central Iberian Peninsula Miocene gypsum biocrusts. Moya et al 49 provided a detailed characterization of a novel phycobiont species ( Asterochloris mediterranea ) detected in the thalli of Cladonia spp., and Moya et al 50 proved that Myrmecia israeliensis was the primary symbiotic microalga in squamulose lichens located in these BSCs. For this investigation, we deal with the crustose community, and this complementarity allows us to overview the symbiotic patterns in the whole lichen community.…”

How did terricolous fungi originate in the Mediterranean region? A case study with a gypsicolous lichenized species

“…PCR reactions were performed following Moya et al. (). The amplified PCR products were sequenced with an ABI 3730XL sequencer, using the BigDye Terminator 3.1 Cycle Sequencing Kit (Applied Biosystems, Foster City, CA).…”

Molecular and morphological diversity of Trebouxia microalgae in sphaerothallioid Circinaria spp. lichens1

“…Sections (90 nm) were cut and mounted as described in Moya et al. (). The sections were observed with a JEOL JEM‐1010 (80 kV) electron microscope, equipped with a MegaView III digital camera, and “AnalySIS” image acquisition software.…”