Vol.:(0123456789) 1 3 Molecular Biology Reports https://doi.org/10.1007/s11033-021-06511-w ORIGINAL ARTICLE Genetic structure of Alhagi (Hedysareae, Fabaceae) populations using ISSR data in Iran Arezoo Amirkhosravi 1  · Younes Asri 2  · Mostafa Assadi 2  · Iraj Mehregan 1 Received: 14 December 2020 / Accepted: 23 June 2021 © The Author(s), under exclusive licence to Springer Nature B.V. 2021 Abstract Alhagi Gagnebin (Fabaceae: Hedysareae) is a small genus of shrubs or subshrubs distributed in temperate and tropical regions of Asia, Europe, and Africa. The exact number of Alhagi species in Iran has been disputable. Studies showed that morphol- ogy, seed protein, and chromosome characters could not clearly delimitate the species boundaries of the genus. In order to determine species boundaries and the population structure of Alhagi species in Iran, eight labeled inter simple sequence repeat (ISSR) primers were used to screen 22 populations including 110 individuals. STRUCTURE, PCoA and clustering analyses of ISSR data were able to clearly split all populations of Alhagi in Iran into two distinct groups. As the populations A. pseudalhagi and A. maurorum jointly formed a group (A. maurorum complex) segregated from those of Alhagi graeco- rum. Further analyses of A. maurorum complex showed a signifcant molecular diference among the studied populations (PhiPT value = 0.213, P = 0.001) as well as a high amount of variability within populations (79%) indicating frequent genetic exchanges. Structure analysis of complex populations (K = 2) showed no distinct genetic pattern related to their geographi- cal distribution. In this study, Alhagi has retrieved the only two species of Alhagi in Iran; A. graecorum and A. maurorum. Keywords Alhagi graecorum · A. maurorum · gene fow · Species delimitation Introduction The family Fabaceae has been introduced as the third largest fowering plant family with more than 760 genera and ca. 19,500 species [1, 2]. The genus Alhagi Gagnebin (Hedys- areae, Fabaceae) is widely distributed throughout northern Africa, the eastern Mediterranean, the Middle East to Cen- tral Asia [3, 4]. This genus is mostly found in the desert and semi-desert regions with salty or rocky soils and its natural distribution was extended by man [5–7]. Previous molecular studies corroborated the monophyly of this genus in a well- supported clade as the frst diverging lineage of the tribe Hedysareae [8–11]. Alhagi is mostly described as peren- nial subshrubs with spiny branches, small simple leaves and legumes. 1–9-seeded, in the shape of articulate and monili- form [12–15]. The exact number of Alhagi species has long been con- troversial. The global number of fve species suggested by Rechinger [14] was reduced to a single variable species by Awmack and Lock [3]. They reduced three recorded species in the Flora Iranica area to two subspecies of A. maurorum Medik i.e. A. maurorum subsp. maurorum and A. maurorum subsp. graecorum (Boiss.) Awmack and Lock. Rechinger [14] recorded three species of Alhagi in Iran: A. mannifera Desf., A. persarum Boiss. & Buhse. and A. pseudalhagi (M. B.) Desv. Sheidai et al. [7] considered A. persarum as a synonym of A. pseudalhagi and Alhagi graecorum as the accepted name for A. mannifera. They also showed that karyotypic characters were not useful in the taxonomy of the genus. It was also indicated that data from analysis of seed storage proteins using SDS-PAGE were not useful in diferentiating Alhagi species [16]. Also, Mabberly [17] introduced Alhagi as a monospecifc genus, A. maurorum. However, our previous study based on molecular and mor- phological study [18] supported the presence of only two species of Alhagi in Iran; A. graecorum and A. maurorum. * Younes Asri asri@rifr-ac.ir 1 Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran 2 Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran