Fostering Conservation via an Integrated Use of Conventional Approaches and High-Throughput SPET Genotyping: A Case Study Using the Endangered Canarian Endemics Solanum lidii and S. vespertilio (Solanaceae).

Pietro Gramazio,Gregory J Anderson,Águedo Marrero,Juli Caujapé-Castells,Santiago Vilanova,Ruth Jaén-Molina,Jaime Prohens

doi:10.3389/fpls.2020.00757

Abstract

Islands provide unique opportunities to integrated research approaches to study evolution and conservation because boundaries are circumscribed, geological ages are often precise, and many taxa are greatly imperiled. We combined morphological and hybridization studies with high-throughput genotyping platforms to streamline relationships in the endangered monophyletic and highly diverse lineage of Solanum in the Canarian archipelago, where three endemic taxa are currently recognized. Inter-taxa hybridizations were performed, and morphological expression was assessed with a common-garden approach. Using the eggplant Single Primer Enrichment Technology (SPET) platform with 5,093 probes, 74 individuals of three endemic taxa (Solanum lidii, S. vespertilio subsp. vespertilio, and S. vespertilio subsp. doramae) were sampled for SNPs. While morphological and breeding studies showed clear distinctions and some continuous variation, inter-taxon hybrids were fertile and heterotic for vigor traits. SPET genotyping revealed 1,421 high-quality SNPs and supported four, not three, distinct taxonomic entities associated with post-emergence geological, ecological and geographic factors of the islands. Given the lack of barriers to hybridization among all the taxa and their molecular differences, great care must be taken in population management. Conservation strategies must take account of the sexual and breeding systems and genotypic distribution among populations to successfully conserve and restore threatened/endangered island taxa, as exemplified by Solanum on the Canary Islands.

Highlights

Islands have long been recognized as biological laboratories because they provide insightful understanding into the evolution, ecology, and conservation of plant species (Baldwin and Warren, 2010; Caujapé-Castells et al, 2010; Warren et al, 2015; Weigelt et al, 2015; Nogales et al, 2016; Stuessy et al, 2017a; Price et al, 2018)
Analysis of Morphology and Pollen Stainability. Both subspecies of S. vespertilio are distinct from S. lidii in terms of leaf length and width, but less distinct in terms of the length/width ratio (Table 3)
Analyses of the artificial hybrids resulting from hand-generated crosses between S. lidii (SL) and either parental subspecies shows that they are mostly distinct as well, with some features similar to one species or the other, but with some hybrids manifesting intermediate characters or heterosis

Summary

Introduction

Islands have long been recognized as biological laboratories because they provide insightful understanding into the evolution, ecology, and conservation of plant species (Baldwin and Warren, 2010; Caujapé-Castells et al, 2010; Warren et al, 2015; Weigelt et al, 2015; Nogales et al, 2016; Stuessy et al, 2017a; Price et al, 2018). A number of molecular-based studies have revealed sharp genetic discontinuities within and between islands in both narrowly distributed and widespread Canarian endemic plant lineages (Rumeu et al, 2014; Jaén-Molina et al, 2015; Puppo et al, 2015; GarcíaVerdugo et al, 2017) These results emphasize the value of comprehensive sampling of populations and genomes for a thorough understanding of evolution prior to the implementation of the necessary components of an effective conservation strategy (Caujapé-Castells et al, unpublished; Díaz-Bertrana and Saturno, 2017)

Objectives

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Results

Conclusion