Molecular and micro-morphological evidences of the genus Cuscuta in Iran

Cuscuta is the only parasitic genus in Convolvulaceae family. This genus is globally distributed, with most species in the tropics, subtropics, and some in the temperate regions. In this study, the micro-morphological features and molecular evidencesof 12 populations from three species of Cuscuta (C. australis, C. campestris,and C. chinensis) have been considered. In total, seven quantitative and two qualitative characters of pollen were selected and measured. The most important characters include: shape, ornamentation of tectum, exine thickness and colpus length of the pollen. Based on this study, the seed shape and surface support at least for separation of C. australis from other two species. Using nuclear (nrDNA ITS) marker, we reconstructed phylogenetic relationships within three species of Cuscuta. This data set was analyzed by phylogenetic methods including Bayesian, Maximum likelihood, and Maximum parsimony. In phylogenetic analyses, all members of three species formed a well-supported clade (PP=1, ML/BS=100/100) and divided into two major clades (A and B). Clade A is composed of specimens of C. australis. Two species of C. campestris and C. chinensis are nested in clade B. Neighbor-Net diagram demonstrated separation of the studied populations.
The results showed that, micro-morphological and molecular data provide reliable evidence for separation of these species.