A cross-city molecular biogeographic investigation of arbuscular mycorrhizas in Conyza canadensis rhizosphere across native and non-native regions

Abstract

Introduction: The ecological processes underlying the suppressive impacts of invasive species on native species diversity, both above- and below-ground, in non-native regions are not well understood. We therefore aimed to investigate the cross-city biogeographic patterns of arbuscular mycorrhizal (AM) diversity in Conyza canadensis rhizosphere in native (North American) and non-native (Kashmir Himalayan) regions. Methods: We recovered AMF spores from rhizospheric soils of Conyza in native and non-native ranges, besides doing so from the uninvaded sites in the introduced region. DNA extracted from AMF spores was processed for cloning and PCR-RFLP of SSU rRNA gene to yield the restriction groups (RGs) followed by their sequence analysis to determine the sequence groups (SGs). Results: The results indicated greater diversity of RGs and SGs in Conyza rhizosphere in native than in non-native sites. In the introduced region, however, the AMF diversity was more in uninvaded than in invaded sites. The species composition of AMF varied significantly between native and non-native regions and so also between invaded and uninvaded habitats. Conclusions: Though difference in AMF diversity between Conyza invaded and uninvaded sites may be attributed to invasion, the role of other evolutionary factors seems likely for differences between the native and non-native regions. We suggest that the ecological processes underlying these evolutionary differences in two biogeographic regions, besides the intensity of urbanization, might play some role in these differences.