Leguminosae or Fabaceae is the third largest flowering plant family, which is an important economically for food production and soil fertility. Four Palestinian genera of the Fabaceae family which are Lens, Vicia, Lathyrus and Pisum have overlapping morphological characteristics among them were the subject of this study. Different molecular techniques are used to determine the relationship and genetic diversity among Leguminosae species of interest including internal transcribed spacers (ITS) sequencing.
This study was performed to identify the phylogenetic relationship among 9 closely related species belong to 4 genera of Leguminosae family: Lens culinaris, Vicia sativa, Vicia palaestina, Vicia peregrina, Vicia faba, Vicia narbonensis, Lathyrus aphaca, Pisum fulvum and Pisum sativum.
Moreover, In spite of that L. culinaris and V. Palaestina are two species belong to different genera; their morphological features are similar to a high degree. Therefore, this study was performed to determine the taxonomic classification of V. palaestina and its phylogenetic relationship to the morphological closely related species L. culinaris.
Morphological classification was conducted for some closely related species of the Leguminosae family in Palestine. The studied plant species were collected from natural wild habitat. Then a representative plant specimen of each species was deposited at An-Najah National University Herbarium. Then molecular analysis was determined using 18S and 28S as universal primers for amplifying and sequencing the ITS region. Evolutionary divergence between sequences was estimated and phylogenetic tree was constructed using the Kimura 2-parameter model and Unweighted Pair Group method, respectively.
Each sample ITS sequence of the examined species as well as Salvia dominica, as an out group, were introduced into the GenBank. The phylogenetic analysis among studied species revealed that, V. palaestina (KJ864941) and P. sativum (KJ864946) have a high average of intraspecies genetic divergence (8.95%). While, low average of intraspecies genetic divergence (1.81%) between V. faba (KJ864957, KJ864958) and V. peregrina (KJ864954) was recorded. Moreover, V. peregrina, V. faba, V. narbonensis, V. palaestina, L. culinaris, and V. sativa were grouped into one clade (clade І). However, V. sativa occupied the farther position in clade І and separated from other species of Vicia genus. While, P. sativum, P. fulvum and L. aphaca were grouped into the same clade (clade ІІ). On the other hand, L. culinaris formed a cluster within the core of Vicia near to V. Palaestina.
In this study, phylogenetic relationship among the closely related species under study of Leguminosae family was detected accurately using ITS sequencing. Also this technique revealed the close relationship between L. culinaris and V. palaestina, as the two species are related to the same genus instead of two different genera.