Abstract Detail

Systematics

Arnelas Seco, Itziar [1], Pérez-Collazos, Ernesto [2], López-Martínez, Josefa [3], Devesa, Juan A. [4], Catalán, Maria del Pilar [5].

Molecular phylogeny and speciation in Valerianella Mill. (Valerianaceae): challenging the systematic value of genetically controlled carpological traits.

Valerianella is a genus of ca. 50 annual diploid species distributed in the Holarctic region; a large number of them grow in the Mediterranean region. Valerianella consists of taxonomically complex groups; these are formed by closely related species-pairs aggregates that show a genetic linkage regulation system for their diagnostic carpological traits (calyx and fruit shapes). This system has been used to separate species and to classify them into distinct sections. We have investigated the evolutionary relationships among 15 species of Valerianella, including a large representation of three species-pairs aggregates (V. locusta-V. carinata, V. coronata-V. pumila, V. dentata-V. rimosa) using 823 samples from 61 populations. We used plastid DNA sequences and nuclear AFLP data to (i) reconstruct the phylogeny of Valerianella; ii) investigate the genetic relationships among the samples, and (iii) elucidate the systematic value of the carpological traits and evaluate the evolution of the fruit-morphotype inheritance systems at both populations and species levels in Valerianella. Plastid and AFLP data concur in the reconstruction of a congruent evolutionary scenario showing the divergence of two main lineages within the core Valerianella tree, the V. sect. Valerianella (V. locusta, V. carinata, V. lusitanica)/ V. sect. Cornigerae (V. echinata) clade and the V. sect. Coronatae (V. coronata, V. pumila, V. discoidea, V. multidentata)/V. sect. Platycoele (V. microcarpa, V. eriocarpa, V. dentata, V. rimosa) clade. Valerianella fusiformis (V. sect. Platycoele) is resolved as an early divergent lineage of a large paraphyletic group that also includes Fedia within it. The AFLP SplitsTree neighbour-network and the plastid ML tree and haplotypic network detected genetic admixture among individuals of the V. locusta-V. carinata, V. coronata-V. pumila, and V. dentata-V. rimosa aggregates as well as shared haplotypes by the species-pairs of each group. Our results support the overall sectional classification of Valerianella, which consist mostly in monophyletic lineages, but reject the classification of its species and the diagnostic value of the carpological traits used to describe them. The fruit-morphotypes characteristic of these species-pairs, regulated by distinct two-linked-loci genotypes, have switched several times along the phylogenies of these aggregates. Populations are genetically structured by geography but not by taxonomy within each group. Taxonomic treatments that subsume the species-pairs into single species represent a natural classification system for Valerianella.

1 - Universidad Técnica Particular De Loja, San Cayetanl Alto S/n, Loja, L, 11-01-608, Ecuador
2 - High Polytechnic School of Huesca, University of Zaragoza, Huesca, Spa, Department of Agricultural and Environmental Sciences, Carretera de Cuarte s/n., Huesca, Huesca, 220071, España
3 - Universidad de Extremadura, Departamento de Biología Vegetal, Ecología y Ciencias de la Tierra, Badajoz, Extremadura, España
4 - Departamento de Botánica, Ecología y Fisiología Vegetal, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Andalucía, España
5 - High Polytechnic School of Huesca, University of Zaragoza, Department of Agricultural and Environmental Sciences, Huesca, Aragón, España

Keywords:
AFLP
Valerianella
phylogeny
Systematics
Valerianella.

Presentation Type: Oral Paper
Session: SYSTI, Systematics I: Euasterids II
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 11:00 AM(EDT)
Number: SYSTI005
Abstract ID:495
Candidate for Awards:None