Lichen phycobiomes as source of biodiversity for microalgae of the Stichococcus-like genera

Abstract

The term phycobiome was recently introduced to designate all the microalgae (primary or non-primary) associated with lichen symbioses. Abundant non-primary symbiotic microalgae are usually obtained from lichen isolations, confirming that thalli are a source of biodiversity and new species. In this study, microalgae were isolated from thalli of Buellia zoharyi, Ramalina farinacea and Parmotrema pseudotinctorum collected in the Iberian Peninsula and the Canary Islands. Excluding Trebouxia phycobionts, 17 strains similar to Stichococcus (Prasiola clade) were obtained. Molecular identification was carried out by nuclear ITS sequencing, and a phylogenetic tree was generated from these sequences, and grouping them into 4 clades: Diplosphaera chodatti, Diplosphaera sp.1. Deuterostichocuccus sp.1. and Tritostichococcus coniocybes. It is also noteworthy that Diplosphaera sp.1 was detected and isolated from three phylogenetically distant lichenized fungi (B. zoharyi, R. farinacea and P. pseudotinctorum), which were sampled in ecologically different localities, namely Tenerife, La Gomera and Castellón. These results reinforce the idea of the constant presence of certain microalgae associated with the lichen thalli which, despite not being the main primary photobiont, probably form part of the lichen’s phycobiomes.

Genomic analysis of Coccomyxa viridis, a common low-abundance alga associated with lichen symbioses

“…The lichen symbioses shown to contain C. viridis are quite diverse and the symbionts include representatives of both main groups of lichen photobionts (green algae and cyanobacteria) and several classes of mycobionts. Combined with reports of other non-photobiont algae frequent in lichens 12 , 15 , this finding raises questions about the place these algae occupy in the lichen symbiosis.…”

“…Compared to lichen photobionts, much less is known about other algae present in lichens. Coming from diverse groups and present in miniscule amounts, these ‘additional’ green algae have recently been termed the phycobiome 12 They are mostly detected in two ways. First, by culturing them from a lichen thallus (e.g., 13 – 16 ).…”

Genomic analysis ofCoccomyxa viridis, a common low-abundance alga associated with lichen symbioses

“…We detected C. viridis in one eighth of analyzed metagenomes. Combined with reports of other non-photobiont algae frequent in lichens [12,15], this finding raises questions about the place these algae occupy in the lichen symbiosis.…”

“…Coming from diverse groups and present in miniscule amounts, these 'additional' green algae have recently been termed the phycobiome [12] They are mostly detected in two ways. First, by culturing them from a lichen thallus (e.g., [13][14][15][16]).…”

High variability of microbial diversity from lampenflora of two bas-reliefs in the Pommery Champagne cellar

“…and Pseudostichococcus sp. sequenced from isolated strains from both Bacchus and Silene, belong to Stichococcus genus and are widely in many environments (freshwaters, marine and terrestrial ecosystems and in harsh polar environments (Proeschold and Darienko, 2020;Chiva et al, 2022).…”