Dioecious plants have a wide distribution in nature and gender effect may cause significant alterations in rhizosphere fungal community and soil properties. However, little is known regarding changes in response to dioecious plants. This study aimed to investigate the effects that the dioecious plant, Populus cathayana, and regions of different arid levels have on the fungal community, mycorrhizal distribution, soil enzymatic activities, and nutrient contents. This study characterized fungal and soil factors from the rhizosphere of the dioecious plant Populus cathayana located in the semi-humid regions (Chengguan), semi-arid regions (Sining, Haiyan) and arid regions (Ulan, Chaka). Rhizosphere soil was collected from each site and gender, and the total fungal genomic DNA was extracted. DNA amplicons from fungal ITS region were generated and subjected to Illumina Miseq sequencing. A total of 5 phyla, 28 classes, 92 orders, 170 families, and 380 genuses were observed. AMF distribution peaked at Chaka, which did not conform to the trend. Gender had significant effects on fungal communities: there were obvious differences in fungal OTUs between genders. Alpha diversity raised at first and then decreased. RDA results showed available P, available K, pH, ALP activity, ammonium N, EC, water content and catalase activity were the key contributors in sample areas. Our results suggested potential interaction effects between plant gender and fungal community.

Arbuscular mycorrhizal (AM) fungi establish symbiosis and improve the lead (Pb) tolerance of host plants. The AM plants accumulate more Pb in roots than their non-mycorrhizal counterparts. However, the direct and long-term impact of AM fungi on plant Pb uptake has been rarely reported. In this study, AM fungus (Rhizophagus irregularis) colonized and non-colonized roots of Medicago truncatula were separated by a split-root system, and their differences in responding to Pb application were compared. The shoot biomass accumulation and transpiration were increased after R. irregularis inoculation, whereas the biomass of both colonized and non-colonized roots was decreased. Lead application in the non-colonized root compartment increased the R. irregularis colonization rate and up-regulated the relative expressions of MtPT4 and MtBCP1 in the colonized root compartments. Rhizophagus irregularis inoculation increased Pb uptake in both colonized and non-colonized roots, and R. irregularis transferred Pb to the colonized root segment. The Pb transferred through the colonized root segment had low mobility and might be sequestrated and compartmented in the root by R. irregularis. The Pb uptake of roots might follow water flow, which is facilitated by MtPIP2. The quantification of Pb transfer via the mycorrhizal pathway and the involvement of MtPIP2 deserve further study.