Strong Genetic Differentiation of Submerged Plant Populations across Mountain Ranges: Evidence from Potamogeton pectinatus in Iran

Abstract

Biogeographic barriers for freshwater biota can be effective at various spatial scales. At the largest spatial scale, freshwater organisms can become genetically isolated by their high mountain ranges, vast deserts, and inability to cross oceans. Isolation by distance of aquatic plants is expected to be stronger across than alongside mountain ridges whereas the heterogeneity of habitats among populations and temporary droughts may influence connectivity and hamper dispersal. Suitable aquatic plant habitats became reduced, even for the widespread submerged Potamogeton pectinatus L. (also named Stuckenia pectinata) giving structure to various aquatic habitats. We compared the level of genetic diversity in a heterogeneous series of aquatic habitats across Iran and tested their differentiation over distances and across mountain ranges (Alborz and Zagros) and desert zones (Kavir), with values obtained from temperate region populations. The diversity of aquatic ecosystems across and along large geographic barriers provided a unique ecological situation within Iran. P. pectinatus were considered from thirty-six sites across Iran at direct flight distances ranging from 20 to 1,200 km. Nine microsatellite loci revealed a very high number of alleles over all sites. A PCoA, NJT clustering and STRUCTURE analysis revealed a separate grouping of individuals of southeastern Iranian sites and was confirmed by their different nuclear ITS and cpDNA haplotypes thereby indicating an evolutionary significant unit (ESU). At the level of populations, a positive correlation between allelic differentiation Dest with geographic distance was found. Individual-based STRUCTURE analysis over 36 sites showed 7 genetic clusters. FST and RST values for ten populations reached 0.343 and 0.521, respectively thereby indicating that allele length differences are more important and contain evolutionary information. Overall, higher levels of diversity and a stronger differentiation was revealed among Iranian P. pectinatus than previously observed for temperate European regions, due to regional differences across mountain ranges over long distances.

Mutational Dynamics of Aroid Chloroplast Genomes II

“…Colocasia esculenta is found in tropical habitat and produces unisexual flowers, whereas the four species of subfamily Lemnoideae produce bisexual flowers and inhabit aquatic habitat ( Mayo et al, 1997 ; Cusimano et al, 2011 ). These species also demonstrated a different rate of mutations, which is consistent with the finding that aquatic and tropical plant have diverse mutation rates ( Abbasi et al, 2016 ; Hu et al, 2017 ; Hart et al, 2019 ; Wang et al, 2020 ). Sampling is therefore sparse in the previous study for a large and ancient monocot family like Araceae, which dates back to the Early Cretaceous period, and is divided into eight diverse subfamilies distributed across the multitude of ecological habitats ( Cusimano et al, 2011 ; Nauheimer et al, 2012 ; Henriquez et al, 2014 ).…”

“…Colocasia esculenta is tropical and belongs to the crown group, whereas the species of Lemnoideae are aquatic and belong to the basal group. Aquatic plants evolve faster as compared to non-aquatic, and tropical plants evolve faster as compared to temperate plants ( Abbasi et al, 2016 ; Hu et al, 2017 ; Hart et al, 2019 ; Wang et al, 2020 ). We found higher rates of mutation in terms of substitutions and InDels in the species of Lemnoideae as compared to other species ( Table 3 ).…”

A Biogeographic Barrier Test Reveals a Strong Genetic Structure for a Canopy-Emergent Amazon Tree Species

“…For sessile organisms such as plants, landscape features and life-history traits (e.g., associated with pollination and dispersal) can restrict migration and increase the amount of genetic variation among populations 3,4,11,12 . Indeed, strong genetic differentiation has been observed across physical barriers for plant species with restricted dispersal abilities 13–15 . For example, highland and mountain ranges acted as effective barriers to gene flow for the tree species Styrax sumatrana 14 , a species rarely dispersed by animals 16 .…”

Spatial genetic structuring in a widespread wetland plant on a plateau: Effects of elevation‐driven geographic isolation and environmental heterogeneity

“…High mountains, especially the Tanggula Mountains, serve as general factors to enhance the population divergence on the QTP by reducing the gene flows between them (Liu et al., 2018). Mountains have also been suggested to act as strong barriers promoting genetic differentiation in S. pectinata (Abbasi et al., 2016).…”

“…This mechanism might create a pattern in which populations at similar elevations/environments present increased gene flow regardless of whether they are spatially adjacent (Wei, Meng, & Jiang, 2013), which is termed isolation by ecology/environment (IBE, Wang & Bradburd, 2014). By contrast, elevation‐driven topographical isolation might induce genetic divergence due to dispersal limitations in the vertical direction or between mountain ranges (Abbasi, Afsharzadeh, Saeidi, & Triest, 2016; Steinbauer et al., 2016), which is analogous to the scenario of genetic isolation by distance (IBD, Slatkin, 1993; Weber, Bradburd, Stuart, Stutz, & Bolnick, 2016).…”