Abstract Detail

Phylogenomics

Ning, Weixuan [1], Meudt, Heidi [2], Nicolas, Antoine [3], Plunkett, Gregory [4], Tate, Jennifer [1].

Phylogenomic analysis of New Zealand polyploid Azorella (Apiaceae).

All angiosperms have at least one whole genome duplication in their evolutionary history. Such polyploidization events are correlated with the genetic and morphological variation of many plant species, and these play an important role in species diversification and new habitat colonization. To have a better understanding of the role of higher polyploidization events in plant speciation and diversification, genera that have species with multiple ploidal levels provide excellent study systems. In New Zealand, Azorella (previously Schizeilema and Stilbocarpa; Plunkett & Nicolas 2017) is a subalpine lineage, comprising 16 endemic species, which may be 4x-, 6x- or 10x-ploids. Unpublished ITS (internal transcribed spacer, nuclear ribosomal DNA, nrDNA) and plastid phylogenetic trees offer low resolution of New Zealand Azorella species relationships and suggest that they originated from diploid Azorella species in Chile and Argentina (Nicolas and Plunkett, pers. comm.). New phylogenomic data are being generated from genome skims (including whole chloroplast genomes and haplotype nrDNA sequences) and low/single copy nuclear genes (LCNG) using the Angiosperm353 bait set. To investigate post-polyploidization diversification traits, the phylogenetic data will be analysed along with divergent traits that are potentially associated with genome duplication, for example leaf morphology, genome size estimates (from flow cytometry), and stomata size (measured using scanning electron microscopy [SEM]). Publicly available environmental database layers for soil, climate, elevation, etc. will also be analysed in conjunction with the phenotypic traits and phylogenomic data to test the following hypotheses: 1) New Zealand polyploid Azorella species originated from hybridization between subantarctic and South American Azorella species, and their diversification is due to reticulation events; 2) the biogeographical origin of New Zealand Azorella was in the subantarctic islands, with subsequent radiation into the South Island of New Zealand and Australia, with a final radiation into the North Island of New Zealand; 3) as a consequence of polyploidization, the higher-ploidal level Azorella have larger genome sizes, longer guard cell lengths, but less stomatal density in comparison to their parental (lower ploidal level) species; 4) after polyploidization, the new Azorella polyploids are more likely to occupy new ecological conditions or niches as compared to their progenitors.

1 - Massey University, School Of Fundamental Sciences, Private Bag 11222, Palmerston North, 4442, New Zealand
2 - Museum Of New Zealand Te Papa Tongarewa, Botany, PO Box 467, Cable St, Wellington, 6140, New Zealand
3 - Manhattan College, Biology, Manhattan College, 4513 Manhattan College Parkway, Riverdale, NY, 10471, USA
4 - Cullman Program for Molecular Systematics, New York Botanical Garden, 2900 Southern Blvd., Bronx, NY, 10458-5126, USA

Keywords:
phylogenomics
Target Enrichment
polyploidy
Azorella
phylogeny
genome size.

Presentation Type: Oral Paper
Session: PHYL1, Phylogenomics I
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 1:15 PM
Number: PHYL1004
Abstract ID:174
Candidate for Awards:None