Phylogenomics and plastome evolution of a Brazilian mycoheterotrophic orchid, Pogoniopsis schenckii

Autor(es)

Klimpert, Nathaniel J. J. ; Mayer, Juliana Lischka Sampaio ; Sarzi, Deise Schroder ; Prosdocimi, Francisco ; Pinheiro, Fabio ; Graham, Sean W. W.

• Tipo de documento: Artigo Científico
• Fonte: AMERICAN JOURNAL OF BOTANY; v. 109, n. 12, p. 21-pg., 2022-11-18.

Resumo

PremisePogoniopsis likely represents an independent photosynthesis loss in orchids. We use phylogenomic data to better identify the phylogenetic placement of this fully mycoheterotrophic taxon, and investigate its molecular evolution. MethodsWe performed likelihood analysis of plastid and mitochondrial phylogenomic data to localize the position of Pogoniopsis schenckii in orchid phylogeny, and investigated the evolution of its plastid genome. ResultsAll analyses place Pogoniopsis in subfamily Epidendroideae, with strongest support from mitochondrial data, which also place it near tribe Sobralieae with moderately strong support. Extreme rate elevation in Pogoniopsis plastid genes broadly depresses branch support; in contrast, mitochondrial genes are only mildly rate elevated and display very modest and localized reductions in bootstrap support. Despite considerable genome reduction, including loss of photosynthesis genes and multiple translation apparatus genes, gene order in Pogoniopsis plastomes is identical to related autotrophs, apart from moderately shifted inverted repeat (IR) boundaries. All cis-spliced introns have been lost in retained genes. Two plastid genes (accD, rpl2) show significant strengthening of purifying selection. A retained plastid tRNA gene (trnE-UUC) of Pogoniopsis lacks an anticodon; we predict that it no longer functions in translation but retains a secondary role in heme biosynthesis. ConclusionsSlowly evolving mitochondrial genes clarify the placement of Pogoniopsis in orchid phylogeny, a strong contrast with analysis of rate-elevated plastome data. We documented the effects of the novel loss of photosynthesis: for example, despite massive gene loss, its plastome is fully colinear with other orchids, and it displays only moderate shifts in selective pressure in retained genes. (AU)

• Processo FAPESP: 15/26479-6 - Estrutura vegetativa de Pogoniopsis schenckii (Orchidaceae: Vanilloideae) e interação desta orquídea aclorofilada com fungos micorrízicos
• Beneficiário: Juliana Lischka Sampaio Mayer
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/22785-8 - O papel da seleção por habitats distintos na manutenção da integridade de espécies em zonas de hibridação natural
• Beneficiário: Fábio Pinheiro
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Regular