New data on three molecular markers from different cellular genomes in Mediterranean accessions reveal new insights into phylogeography of Pisum sativum L. subsp. elatius (Bieb.) Schmalh.

Abstract

Twelve accessions classified as Pisum sativum subsp. elatius, mostly from West and Central Mediterranean, were analysed for three markers from different cellular genomes: rbcL (plastid genome), coxI (mitochondrial genome) and SCA (nuclear genome). Based on geographical distribution of their allele combinations analysed in this and the earlier study, we suggest a putative history of wild representatives of P. sativum. The ancestor of this species belonged to lineage A (coxI+, rbcL+, SCA ^f); it appeared in East Mediterranean, then spread westward most probably during one of the Pleistocene coolings when the sea was smaller, so that representatives of lineage A remained in the Eastern Mediterranean and on the islands of Sicily and Menorca. Mutation leading to the loss of the restriction site for PsiI in coxI−, gave rise to lineage C (coxI−, rbcL+, SCA ^f) which spread widely in the Mediterranean and is now found in France, Greece and Ethiopia. Mutation leading to rbcL− gave rise to lineage D (coxI−, rbcL−, SCA ^f), now found in Egypt (P. sativum subsp. jomardii) and Spain. Mutational transition of SCA ^f to SCA ^s most probably took place in North-Eastern Mediterranean since the resulting lineage B (coxI−, rbcL−, SCA ^s) now occupies the Tauro-Caucasian area. In Asia Minor and North Israel, line B met the ancestral line A so that both lines coexist there presently. The lineage B gave rise to the cultivated P. sativum subsp. sativum.