| Full text | |
| Author(s): |
Klimpert, Nathaniel J. J.
;
Mayer, Juliana Lischka Sampaio
;
Sarzi, Deise Schroder
;
Prosdocimi, Francisco
;
Pinheiro, Fabio
;
Graham, Sean W. W.
Total Authors: 6
|
| Document type: | Journal article |
| Source: | AMERICAN JOURNAL OF BOTANY; v. 109, n. 12, p. 21-pg., 2022-11-18. |
| Abstract | |
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) | |
| FAPESP's process: | 15/26479-6 - Vegetative structure of the achlorophyllous orchid Pogoniopsis schenckii (Vanilloideae) and its interaction with mycorrhizal fungi |
| Grantee: | Juliana Lischka Sampaio Mayer |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 16/22785-8 - The role of habitat selection in the maintenance of species integrity in natural hybrid zones |
| Grantee: | Fábio Pinheiro |
| Support Opportunities: | BIOTA-FAPESP Program - Regular Research Grants |