Diversidade de fotobiontes de liquens avaliada por metabarcoding da região 16S do rRNA: estudo de caso com Dirinaria confluens (Fr.) D.D. Awasthi (Caliciaceae, Ascomycota liquenizados)

Abstract

In studies that evaluate genetic diversity based on metagenomic analyses, the amplified sequences represent a portion of the organisms that live there. However, due to the genetic similarity resulting from common ancestry, universal primers often lead to the amplification and sequencing of DNA from phylogenetically distant species present in the same environmental DNA sample. In this study, bioinformatics analyses were carried out on the v4 region of the 16S ribosomal gene, used in principle to analyze only the community of bacteria present in thalli of the lichenized fungus Dirinaria confluens and D. confluens var. coccinea (Caliciaceae, Ascomycota). Analysis of 38 samples revealed that a significant portion of the sequences did not belong to the v4 region of bacteria but to the ribosomal rrs gene of the cpDNA of green algae of the genus Trebouxia sp., the main photobiont associated with D. confluens. The Trebouxia sequences were analyzed separately, and 64 different haplotypes were detected. Phylogenetic analyses confirmed that these are closely related cpDNA sequences, and it is not possible to define at first whether they all belong to the same species of Trebouxia. The present work demonstrates the potential of using bioinformatics analyses of high-throughput sequencing made with bacterial v4 16S primers to study phycobionts associated with lichenized fungi.