Phylogeny and Ecology of Trebouxia Photobionts From Bolivian Lichens

Abstract

In the past few years, new phylogenetic lineages in Trebouxia were detected as a result of molecular approaches. These studies included symbiont selectivity in lichen communities, transects along altitudinal gradients at local and global scales and the photobiont diversity in local populations of lichen-forming fungal species. In most of these studies, phylogenetic and haplotype analyses based on the internal transcribed spacer (ITS) locus have continuously allowed the recognition of new monophyletic lineages, which suggests that still numerous undiscovered Trebouxia lineages can be hidden in lichens from unexplored areas, especially in the tropics. Here, we estimated the biodiversity of photobionts in Bolivian Andean vegetation and assessed their specificity. About 403 lichen samples representing 42 genera, e.g., Haematomma, Heterodermia, Hypotrachyna, Lecanora, Lepra, Leucodermia, Parmotrema, Pertusaria, Polyblastidium, and Usnea, containing Trebouxia photobionts, were analyzed. ITS ribosomal DNA (rDNA) and rbcL markers were used. We obtained Trebouxia sequences from Bolivian samples belonging to already described clades A, C, I, and S. Thirty-nine Trebouxia lineages were distinguished within these clades, while 16 were new. To reveal the structure of the community of Bolivian photobionts and their relationships with mycobionts, the comparative effects of climate, altitude, geographical distances, substrate, and habitat type, as well as functional traits of lichens such as growth forms, propagation mode and secondary metabolites, were analyzed. Furthermore, new Bolivian records were included in analysis on a global scale. In our study, the mycobiont genus or even species are the most important factors correlated with photobiont identity. Moreover, we revealed that the community of Bolivian photobionts is shaped by altitude.

High Andean Steppes of Southern Chile Contain Little-Explored Peltigera Lichen Symbionts

“…The photobiont partner is crucial in the whole symbiosis survival in these conditions since it participates through different mechanisms to mitigate or tolerate different stressors [ 6 , 66 ], which could be aggravated due to climate change [ 67 ]. This and other studies [ 14 , 37 , 68 , 69 , 70 , 71 , 72 ] highlight the importance of performing studies in still-understudied areas regarding biodiversity, which can be essential for studying adaptation strategies. Considering the particularity of the climatic factors in the studied environments and their influence in shaping photobiont distributions and their association patterns [ 23 , 73 , 74 ], the genetic diversity found in this work may not be widely distributed in the whole Andean landscape but is restricted to specific patches.…”

Punctelia borreri and P. subrudecta (Parmeliaceae) associate with a partially overlapping pool of Trebouxia gelatinosa lineages

“…2021; Kosecka et al . 2022). The phylogenetic approach indicated that all genetic lineages could be assigned to Trebouxia gelatinosa .…”

“…(2020) and Kosecka et al . (2022) indicated that Punctelia rudecta (Ach.) Krog and P. hypoleucites (Nyl.)…”

Trebouxia lynnae sp. nov. (Former Trebouxia sp. TR9): Biology and Biogeography of an Epitome Lichen Symbiotic Microalga

“…The number of species-level lineages recognized in Trebouxia increases as soon as new ecological niches or different lichen symbioses are investigated (e.g., [ 10 , 11 , 12 ]). However, only 30 Trebouxia species-level lineages have so far been formally described based on their cell morphology/ultrastructure and genetic diversity [ 6 , 13 , 14 , 15 , 16 ].…”

“…TR9 was genetically and ultrastructurally different. The discovery of the presence of two photobionts in a single thallus made the lichen R. farinacea a model/reference system to study the photobiont coexistence in lichens (e.g., [ 10 , 11 , 29 , 30 ]). The application of the DNA metabarcoding approach corroborated the coexistence of the two photobionts ( T. jamesii and Trebouxia sp.…”