The commercial cultivation of passion fruit can be affected by many diseases, which might induce sever fruit yield losses and significant life cycle reduction of the crop. In some situations disease incidence can make the passion fruit production not economically viable. Sources of resistance against several pathogens have been identified in accessions of Passiflora germplasm. In the present research we evaluate by using RGAs ("resistance gene analogs") markers the genetic diversity of accessions belonging to eight wild species (P. setacea, P. nitida, P. serratodigitata, P. caerulea, P. gibertii, P. odontophyla, P. eduli, and P. coccinea) as well as one interspecific hybrid (P. setacea. x P. coccinea). A remarkable diversity was observed among the RGA eletrophoretic profiles of the accessions, allowing the annotation of 96 polymorphic amplicons able to discriminate at least one pair of accessions. The levels of genetic dissimilarity in this group of Passiflora accessions (using exclusively this collection of RGA markers) ranged from 0.40 to 0.89. The sequence analysis of a subgroup of RGA amplicons indicated that they correspond to genomic regions that encompass typical disease resistance gene motifs described in other plant species. Our results indicate a quite variable structural repertoire of RGA segments in Passiflora species with many of them being potentially useful as molecular markers for germplasm fingerprinting systems and also for assisted selection strategies in disease resistance breeding programs in this crop.
Passiflora; molecular markers; RGAs; polymorphic
