HOMOLOGY BETWEEN THE FABA BEAN AND PEA MAPS WITH THE MODEL SPECIES Medicago truncatula USING STS

Abstract

The existence of conserved regions in different species (synteny) allows the identification of genes or genomic regions with similar functions. Thus, a marker tightly linked to a trait in a certain species might be present in other species where this marker can be amplified. The objective was to amplify functional STS markers (Sequence Tagged Sites) from the model species Medicago truncatula and from Pisum sativum, in Vicia faba, to identify polymorphisms by means of restriction enzymes, and finally to map them into the genome of this species. The final aim was to establish possible homologies among the genomes of these species. To do so, an F₆ population of 165 lines derived from the cross Vf6 x Vf136 was used. A total of 57 STS primers were analyzed, 37 from M. truncatula and 20 from P. sativum. Mapping of the polymorphic markers was performed with the program MAPMAKER V2.0. Although 10 M. truncatula STS and six from P. sativum were successfully amplified, only five of them showed polymorphism: four from M. truncatula and one from P. sativum. Results allowed to deduce that Sub-group I.A from chromosome 1 in V. faba is homologous to GL05 from M. truncatula, due to the localization of STS MTU04. PCT, located in sub-group I.B from chromosome 1, indicates homology with GL04 from M. truncatula. Location of NPAC and AATC markers mapped in the sub-group II.A from chromosome 2, allowed to infer homology with GL03 from M. truncatula and GL03 from P. sativum, respectively. Finally, VBP1 located in chromosome 5 indicates correspondence with the GL07 from M. truncatula. The obtained results represent an advance in the synteny studies among these species and will be corroborated as more standard markers distributed throughout their genomes are available.