Identification of Prosopis juliflora and Prosopis pallida Accessions Using Molecular Markers

Abstract

There has been much taxonomic confusion over the identification of Prosopis species, especially where introduced. Prosopis juliflora is the most widespread species in the arid and semi-arid tropics, although it has been confused with other species, particularly the closely related Prosopis pallida. In this study, RAPDs markers were used for the first time to distinguish between these species. Eighteen primers were used in amplification reactions, which yielded an average of 120 bands per accession. A dendrogram showing genetic similarities among accessions was constructed using UP-GMA cluster analysis and the Nei and Li similarity coefficient. The genetic similarity observed between P. juliflora and P. pallida is similar to the value in sympatric Prosopis species in North America, and reconsideration of the series rank in section Algarobia is suggested. Species-specific markers confirmed that material in Burkina Faso is P. juliflora, but suggested that material collected in Brazil, Cape Verde and Senegal is P. pallida, whereas this has previously been identified as P. juliflora.

RAPD and microsatellite transferability studies in selected species of Prosopis (section Algarobia) with emphasis on Prosopis juliflora and P. pallida

“…Recent works on ploidy by Harris et al (2003) and Trenchard et al (2008) showed that the two species can be distinguished on the basis of their morphology and ploidy. RAPD markers also were useful in differentiating the two species (Landeras et al 2006). However, results obtained suggest that P. juliflora is closer to the four North American species identified in this study than to P. pallida.…”

“…The two species are similar in leaf morphology and tree form, and Pasiecznik et al (2001) assumed that naturally occurring hybridization in their overlapping native ranges led to the difficulty in differentiating the two species. Molecular studies were useful in differentiating the two species and reported them to be closely related (Landeras et al 2006), and this and another study (Harris et al 2003) confirmed that P. juliflora was the only known naturally occurring tetraploid species in the genus, though the origin of P. juliflora remained unresolved. Further molecular analysis was noted to be essential in order to fully exploit these species especially in the areas where they are introduced.…”

“…It could be safely concluded that P. pallida is one of the parents of the hybrid, though the status of P. chilensis could not be confirmed. In their study using RAPD markers, Landeras et al (2006) suggested this possibility of P. chilensis as the other putative parent but their results were not conclusive. In the group average cluster analysis in this study, P. pallida and the hybrid formed a cluster with a similarity index of 0.582.…”

“…A less significant marker can also be seen in P. chilensis. In their study using RAPD markers, Landeras et al (2006) identified a similar marker using this primer in all the P. pallida accessions. These findings suggest that the hybrid is closely related to P. pallida.…”

“…Studies by Landeras et al (2006) have identified RAPD markers which are specific to the P. Juliflora-P. pallida complex and also belonging to section Algarobia. These markers could identify the genetic similarity between those species.…”