Inferências genômicas e filogenéticas dos genomas acessórios das Polytrichaceae Antárticas: Polytrichum strictum Menzies ex Brid. e Polytrichum juniperinum Hedw.

Abstract

The Polytrichaceae family has several representants on the Antarctic continent, including Polytrichum strictum Menzies ex Brid. Considered a bipolar organism, because it develops in both the Arctic and Antarctica Continent, it still need studies to clarify its taxonomic classification, since several times it was conducted as a variant of Polytrichum juniperinum Hedw due to its morphology be similar to the species and its true origin still not be clear. In study, it was suggested that P. juniperinum could be the maternal ancestor of P. strictum, but the analysis presented incongruence’s. There are still no molecular studies of the specimens from the poles, let alone genomic approaches of the genus Polytrichum. With advent of new generation sequencing technologies, organellar genomes become as tool for phylogenetic studies, as they provide data on genome content and genome architecture, as well as complementary phylogenetic inferences about the evolutionary history of species. In this work, the sequence of the chloroplast (cpDNA) and mitochondrial (mtDNA) genomes of P. strictum and P. juniperinum was determined with the objective of analyze and structurally characterize the accessory genomes of the genera Polytrichum and infer in the phylogenetic relationships between P. strictum and P. juniperinum.The accessory genomes of the species were sequenced on an Ion Torrent NGS sequencer. Assembly, annotation, alignment, phylogeny construction and syntenic analysis were performed in sílico with specific software. The P. juniperinum cpDNA has 55,168 bp comprising 51 genes, 31 tRNAs, 4 rRNAs and 19 proteins related to photosystem I and II. The P. juniperinum mtDNA comprises a total of 88,021 bp with 67 genes including 19 tRNAs, 5 rRNAs, and 12 proteins related to oxidative metabolism. The P. strictum cpDNA has 20,183 bp comprising 45 genes, 14 tRNAs, 4 rRNAs, and 18 proteins from photosystem I and II. The P. strictum cpDNA has 20,183 bp comprising 45 genes, 14 tRNAs, 4 rRNAs, and 18 proteins from photosystem I and II. The P. strictum mtDNA has 58,896 bp containing a total of 62 genes, 19 tRNAs, 5 rRNAs, and 13 proteins related to oxidative metabolism. In the phylogenetic analyzes with cpDNA and mtDNA the consensus trees presented some differences in the branching pattern, but P. juniperinum and P. strictum were grouped in the same clade. This information generated from cpDNA and mtDNA of P. juniperinum and P. strictum provide a contribution to future phylogenetic studies with the specimens from Arctic.