Variações morfológicas, químicas e genéticas de Stereocaulon alpinum Laurer (Stereocaulaceae) e seus fotobiontes da região sul da América do Sul e Antártica Marítima

Abstract

Lichens result from the symbiotic association between fungi and photobionts (green algae and/or cyanobacteria), occurring in diverse habitats, including extreme environments, potentiated among the main components of polar and alpine vegetation. Stereocaulon alpinum is widely used in biotechnological studies that bioprospect compounds, such as antimicrobial, antimitotic, cytotoxic, inhibitory, toxicological and immunomodulatory enzymes. The species was billed as polyphyletic and not bipolar. This study uses an integrative approach, including morphological, anatomical, chemical, and genetic data of S. alpinum specimens collected in both hemispheres (northern and southern). A total of 35 specimens of the species were fulfilled, and for the phylogenetic analyses, the DNA sequences of the mycobiont (ITS and β-tubulin) and photobionts, green algae (actin gene), and cyanobacteria (16S gene) were used, espectively. From the completed copies, we generated a total of 67 sequences. Its morphology has slight variations within the species in the height and disposition of pseudopodetia, color stages of cephalodia, the shape of phyllocladia, and thickness of tomentum, but none that genetically diversifies, making it a species with high phenotypic plasticity. In this study, the chemistry of S. alpinum proved to be diverse without phylogenetic and geographic patterns. The photobionts (green algae and cyanobacteria) were Asterocholoris sp. and Nostoc sp. respectively, reinforcing the association of these genera with S. alpinum. Therefore, the study revealed that an S. alpinum type is a monophyletic and bipolar species.