Plant Genetic Resources

Research Article

Phylogeny, phylogeography and genetic diversity of the Pisum genus

Petr Smýkala1 c1, Gregory Kenicera2, Andrew J. Flavella3, Jukka Corandera4, Oleg Kosterina5, Robert J. Reddena6, Rebecca Forda7, Clarice J. Coynea8, Nigel Maxteda9, Mike J. Ambrosea10 and Noel T. H. Ellisa10

a1 Agritec Plant Research Limited, Department of Biotechnology, Zemedelská 2520/16, CZ-787 01 Šumperk, Czech Republic

a2 Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK

a3 Division of Plant Sciences, University of Dundee at SCRI, Invergowrie, Dundee DD2 5DA, UK

a4 Department of Mathematics, Abo Akademi University, Biskopsgatan 8, FIN-20500 Åbo, Finland

a5 Institute of Cytology and Genetics, Siberian Department of Russian Academy of Sciences, 630090 Novosibirsk, Russia

a6 Australian Temperate Field Crops Collection, Horsham VIC 3401, Australia

a7 Melbourne School of Land and Environment, The University of Melbourne, Victoria 3010, Australia

a8 USDA – Agricultural Research Service, WSU, Pullman WA99164, USA

a9 School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK

a10 John Innes Centre, Colney, Norwich NR4 7UH, UK

Abstract

The tribe Fabeae (formerly Vicieae) contains some of humanity's most important grain legume crops, namely Lathyrus (grass pea/sweet pea/chickling vetches; about 160 species); Lens (lentils; 4 species); Pisum (peas; 3 species); Vicia (vetches; about 140 species); and the monotypic genus Vavilovia. Reconstructing the phylogenetic relationships within this group is essential for understanding the origin and diversification of these crops. Our study, based on molecular data, has positioned Pisum genetically between Vicia and Lathyrus and shows it to be closely allied to Vavilovia. A study of phylogeography, using a combination of plastid and nuclear markers, suggested that wild pea spread from its centre of origin, the Middle East, eastwards to the Caucasus, Iran and Afghanistan, and westwards to the Mediterranean. To allow for direct data comparison, we utilized model-based Bayesian Analysis of Population structure (BAPS) software on 4429 Pisum accessions from three large world germplasm collections that include both wild and domesticated pea analyzed by retrotransposon-based markers. An analysis of genetic diversity identified separate clusters containing wild material, distinguishing Pisum fulvum, P. elatius and P. abyssinicum, supporting the view of separate species or subspecies. Moreover, accessions of domesticated peas of Afghan, Ethiopian and Chinese origin were distinguished. In addition to revealing the genetic relationships, these results also provided insight into geographical and phylogenetic partitioning of genetic diversity. This study provides the framework for defining global Pisum germplasm diversity as well as suggesting a model for the domestication of the cultivated species. These findings, together with gene-based sequence analysis, show that although introgression from wild species has been common throughout pea domestication, much of the diversity still resides in wild material and could be used further in breeding. Moreover, although existing collections contain over 10,000 pea accessions, effort should be directed towards collecting more wild material in order to preserve the genetic diversity of the species.

Correspondence:

c1 Corresponding author. E-mail: smykal@agritec.cz

Metrics
0Comments