Abstract Detail

Phylogenomics

Lin, Qianshi [1], Lam, Vivienne K. Y. [2], Gomez, Marybel Soto [3], Marques, Isabel [1], Merckx, Vincent [5], Graham, Sean W. [1].

Mitochondrial phylogenomics of mycoheterotrophic lineages of monocots.

Much progress has been made in monocot phylogeny and classification, although several major uncertainties persist. Mycoheterotrophic lineages (plants that rely on fungi for their nutritional needs) have been particularly difficult to place in monocot phylogeny because of substantial morphological modification, elevated substitution rates in all three plant genomes, and gene loss in the plastid genome. Here we report on progress in using mitochondrial genomes to infer higher-order relationships in monocot clades that include fully mycoheterotrophic lineages, with a focus on three orders with an especially rich representation of mycoheterotrophic lineages: Dioscoreales, Pandanales and Petrosaviales. In Dioscoreales we retrieved mitochondrial gene sets for eight of ~nine photosynthetic genera, and eight mycoheterotrophic species from Burmanniaceae and Thismiaceae. In Pandanales we retrieved full mitochondrial gene sets representing up to ~37 mitochondrial genes from 23 of ~25 photosynthetic genera and one mycoheterotrophic genus (Sciaphila; Triuridaceae). Several species of Petrosavia and both genera in Petrosaviales are included, along with mycoheterotrophic representatives of Asparagales (Geosiris in Iridaceae) and Liliales (Corsiaceae). We use these new data for phylogenomic analyses and to explore the molecular evolution of the mitochondrial genes. Mitochondrial genes generally evolve more slowly than plastid and nuclear genes, but there appears to be proportionately less rate elevation in mycoheterotroph mitochondrial genomes than in their plastid counterparts. Inferred relationships for autotrophic and heterotrophic lineages based on mitochondrial gene sets are generally well supported, and correspond well to plastid-based inferences for the same taxa. The phylogenetic position and monophyly of Thismiaceae, a mycoheterotrophic family in Dioscoreales, have been problematic. Here we confirm Thismiaceae to be distantly related to Burmanniaceae. This conflicts with the treatment of these families in recent angiosperm classifications, but agrees with few-gene molecular phylogenetic studies based on mitochondrial and nuclear data. We also infer non-monophyly of Thismiaceae and convergent losses of photosynthesis in this clade.

1 - University Of British Columbia, Botany, Bio Sciences BLDG, 6270 University BLVD, Vancouver, BC, V6T 1Z4, Canada
2 - University Of British Columbia, Botany, Bio Sciences BLDG, 6270 University BLVD, Vancouver, BC, V6T 1Z4, Canada
3 - University Of British Columbia, Botany, 118-425 E11th Ave, Vancouver, BC, V5T 4K8, Canada
4 - University Of British Columbia, Botany, Bio Sciences BLDG, 6270 University BLVD, Vancouver, BC, V6T 1Z4, Canada
5 - Leiden University, Naturalis Biodiversity Center, Darwinweg 2, Leiden, 2300RA, Netherlands

Keywords:
mitochondrial genome
higher-order classification
mycoheterotrophic plants
mycoheterotrophy
Pandanales
Petrosaviales
Dioscoreales
Burmanniaceae
Thismiaceae.

Presentation Type: Oral Paper
Session: 1, Phylogenomics I
Location: 101/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 11:15 AM
Number: 1013
Abstract ID:445
Candidate for Awards:None