Molecular Phylogeny of the Genus <italic>Lathyrus</italic> (<italic>Fabaceae-Fabeae</italic>) Based on cpDNA matK Sequence in Iran

Abstract

<span style="color: windowtext;">Background<span lang="AR-SA" dir="rtl">: </span></span><span style="color: windowtext;">More than 60 species of the genus <em>Lathyrus</em> are distributed in Southwest Asia. It is the second largest genus of the tribe Fabeae, after <em>Vicia</em>, in the region (and in Iran with 23 species). In the regional Flora (Flora of Turkey<em>, </em>FloraIranicaand flora of Iran), the genus has been divided into 9-10 sections. Here we analyzed the phylogeny of <em>Lathyrus</em> and its relationship with <em>Pisum</em> based on plastid gene matK sequences.</span> <span style="color: windowtext;">Objectives:</span><span style="color: windowtext;">The present study utilized several approaches including maximum parsimony, Bayesian and maximum likelihood methods to evaluate the monophyly and relationship within the genus <em>Lathyrus</em>, both at the sectional level and species level, mainly based on the taxa growing in Iran.</span> <span style="color: windowtext;">Materials and Methods:</span><span style="color: windowtext;">A total of 52 accessions, representing 38 species of <em>Lathyrus</em>, three species of <em>Pisum</em> and four species of <em>Vicia</em> and <em>Lens</em> as out-groups, were analyzed for reconstructing the phylogenetic relationship using chloroplast gene matK sequences. Maximum parsimony, Bayesian and maximum likelihood methods were used to construct phylogenetic trees.</span> <span style="color: windowtext;">Results:</span><span style="color: windowtext;">The present study indicated that <em>Pisum</em> was nested among <em>Lathyrus</em> species. Two members of the <em>Lathyrus</em> section, <em>Clymenum</em> (<em>Lathyrus ochrus</em> and <em>L. Clymenum</em>) with <em>Pisum,</em> formed a weakly supported clade as sister to the larger polytomy comprising the remainder of the <em>Lathyrus</em> species. Several sections of <em>Lathyrus</em> including <em>Lathyrostylis</em>, <em>Lathyrus</em> and <em>Clymenum</em> were monophyletic. <em>Lathyrus roseus</em> (of the monotypic section <em>Orobon</em>) were nested among the members of section <em>Lathyrus</em>. The newly taxon described species <em>L. alamutensis</em>, endemic to Iran, were nested among other species of <em>Lathyrostylis</em>. <em>Linearicarpus</em>, <em>Orobus</em> and <em>Pratensis</em> were not monophyletic sections. <em>Pratensis</em> and the monotypic section <em>Aphaca</em> were the closest taxa. In our analysis, <em>L. Pratensis</em> formed a sister group relationship with the <em>Aphaca</em> clade, not its own section.</span> <span style="color: windowtext;">Conclusions:</span><span style="color: windowtext;">Shimodaira-Hasegawa (SH) test of the matK dataset showed that all analyzed <em>Lathyrus</em> species formed their own clade and <em>Pisum</em> was sister to them. Furthermore, when we removed the two above-mentioned <em>Lathyrus</em> species, the analysis retrieved <em>Pisum,</em> as a well-supported clade being sister to the <em>Lathyrus</em> calde.</span>