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Article|01 Sep 2020|OPEN
ddRAD sequencing-based genotyping for population structure analysis in cultivated tomato provides new insights into the genomic diversity of Mediterranean ‘da serbo’ type long shelf-life germplasm
Salvatore Esposito1, Teodoro Cardi1, Gabriele Campanelli2, Sara Sestili2, María José Díez3, Salvador Soler3, Jaime Prohens3 & Pasquale Tripodi1,
1CREA Research Centre for Vegetable and Ornamental Crops, Pontecagnano, (SA), Italy
2CREA Research Centre for Vegetable and Ornamental Crops, Monsampolo del Tronto (AP), Tronto, Italy
3Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, 46022 Valencia, Spain

Horticulture Research 7,
Article number: 20134 (2020)
doi: 10.1038/hortres.2020.134
Views: 129

Received: 17 Apr 2020
Revised: 10 Jun 2020
Accepted: 19 Jun 2020
Published online: 01 Sep 2020

Abstract

Double digest restriction-site associated sequencing (ddRAD-seq) is a flexible and cost-effective strategy for providing in-depth insights into the genetic architecture of germplasm collections. Using this methodology, we investigated the genomic diversity of a panel of 288 diverse tomato (Solanum lycopersicum L.) accessions enriched in ‘da serbo’ (called ‘de penjar’ in Spain) long shelf life (LSL) materials (152 accessions) mostly originating from Italy and Spain. The rest of the materials originate from different countries and include landraces for fresh consumption, elite cultivars, heirlooms, and breeding lines. Apart from their LSL trait, ‘da serbo’ landraces are of remarkable interest for their resilience. We identified 32,799 high-quality SNPs, which were used for model ancestry population structure and non-parametric hierarchical clustering. Six genetic subgroups were revealed, clearly separating most ‘da serbo’ landraces, but also the Spanish germplasm, suggesting a subdivision of the population based on type and geographical provenance. Linkage disequilibrium (LD) in the collection decayed very rapidly within <5 kb. We then investigated SNPs showing contrasted minor frequency allele (MAF) in ‘da serbo’ materials, resulting in the identification of high frequencies in this germplasm of several mutations in genes related to stress tolerance and fruit maturation such as CTR1 and JAR1. Finally, a mini-core collection of 58 accessions encompassing most of the diversity was selected for further exploitation of key traits. Our findings suggest the presence of a genetic footprint of the ‘da serbo’ germplasm selected in the Mediterranean basin. Moreover, we provide novel insights on LSL ‘da serbo’ germplasm as a promising source of alleles for tolerance to stresses.