Effects Of Male And Female Populus Cathayana On Rhizosphere Soil Bacteria And Arbuscular Mycorrhizal Fungi

Soil microorganisms play a key role in regulating biogeochemical cycles and maintaining ecosystem functions.Increased understanding of plant and soil microbial interactions will help improve the productivity and stability of terrestrial ecosystems.Dioecious plants have been extensively studied for their sexual dimorphism in terms of morphology,physiology,and nutrient access.However,the response of the rhizosphere soil microbial community to sex in dioecious plants is largely unknown.In this study,male and female Populus cathayana plants were used as research objects,using high-throughput sequencing technology,The rhizosphere soil bacteria and arbuscular mycorrhizal fungi（AMF）of male and female P.cathayana growing in the soil of pure male P.cathayana forest（MM soil）,soil of pure female P.cathayana forest（FF soil）and heterogeneous soil（MF soil）were studied.By combining stable isotope labeling and ¹³C-PLFA-SIP technology,the relationship between male and female P.cathayana and rhizosphere soil microorganisms was explored,and the main results were obtained as follows:（1）Effects of different soil conditions on carbon allocation of male and female P.cathayana.Under different soil conditions,there were significant differences in biomass accumulation and defensive substance content between male and female P.cathayana,and female invested more energy in defense against external environment than male,However,the photosynthetic capacity,nitrogen absorption rate and sucrose content in leaves and stems of female were significantly lower than those of male,indicating that male and female P.cathayana showed sexual dimorphism in growth,defense and nutrient acquisition under different soil conditions,which indirectly affected the rhizosphere soil bacteria and AMF of male and female P.cathayana.（2）Effects of different soil conditions on rhizosphere soil bacteria of male and female P.cathayana.Under heterogeneous soil conditions,soil pH value,available phosphorus content and ammonium nitrogen content of male were significantly higher than that of female,but soil polyphenol oxidase activity of male was significantly lower than that of female.When male P.cathayana grew in the soil of pure female forest,its soil microbial community used the most photosynthetic products,and this phenomenon also appeared in the soil compartment of pure female forest of male P.cathayana under heterogeneous soil conditions.For the rhizosphere soil bacterial communities of male and female P.cathayana,the level richness index of soil bacterial phylum（Chao1 index）was significantly affected by the interaction between sex and soil under heterogeneous soil conditions.The dominant bacteria in each treatment were Proteobacteria,Actinobacteria,Firmicutes and Bacteroidetes.At the genus level,there were significant differences in rhizosphere soil bacterial community structure among different treatments.The male P.cathayana enriched more bacteria genera that assisted plant nutrient absorption,while the female P.cathayana enriched more bacteria genera that were resistant to stress.（3）Effects of different soil conditions on rhizosphere soil AMF of male and female P.cathayana.For the AMF community in rhizosphere soil of male and female P.cathayana,the interaction effect between sex and soil has a significant effect on the horizontal richness index of soil AMF（Chao1 index）under heterogeneous soil conditions.The dominant species of the treatments were Phragmoplastophyta,Mucoromycota,Basidiomycota,Chytridiomycota;Significance analysis of differences in community structure showed that there were significant differences in AMF community structure among treatments under homogeneous soil conditions.Canonical correlation analysis showed that ammonium nitrogen content was the main driving factor of AMF community structure in rhizosphere soil.LEfse analysis showed that the AMF biomarkers in the rhizosphere soil of male and female P.cathayana increased gradually from homogeneous soil to heterogeneous soil.