Institute of Applied Biotechnology, School of Life Science, Shanxi Datong University, Datong, 037009, Shanxi, China.
State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Lingnan Guangdong Laboratory of Modern Agriculture, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
Sci Rep. 2021 Sep 15;11(1):18403. doi: 10.1038/s41598-021-97674-w.
The sex-specific physical and biochemical responses in dioecious plants to abiotic stresses could result in gender imbalance, and how to ease the current situation by microorganisms is still unclear. Using native soil where poplars were grown, growth parameters, soil physicochemical properties in the rhizosphere soil of different sexes of Populus cathayana exposed to salt stress and exogenous arbuscular mycorrhizal (AM) inoculation were tested. Besides, the sex-specific microbial community structures in the rhizosphere soil of different sexes of Populus cathayana were compared under salt stress. To identify the sex-specific microbial community characteristics related to salinity and AM symbiosis, a combined qPCR and DGGE method was used to monitor microbial community diversity. Seedlings suffered severe pressure by salt stress, reflected in limited growth, biomass, and nutrient element accumulation, especially on females. Exogenous AM inoculation treatment alleviated these negative effects, especially under salt treatment of 75 mM. Compared with salt effect, exogenous AM inoculation treatment showed a greater effect on soil physical-chemical properties of both sexes. Based on DGGE results, salt stress negatively affected fungal richness but positively affected fungal Simpson diversity index, while exogenous AM inoculation treatment showed the opposite effect. Structural equation modeling (SEM) was performed to show the causal relationships between salt and exogenous AM inoculation treatments with biomass accumulation and microbial community: salt and exogenous AM inoculation treatment showed complicated effects on elementary concentrations, soil properties, which resulted in different relationship with biomass accumulation and microbial community. Salt stress had a negative effect on soil properties and microbial community structure in the rhizosphere soil of P. cathayana, whereas exogenous AM inoculation showed positive impacts on most of the soil physical-chemical properties and microbial community status.
雌雄异株植物对非生物胁迫的生理和生化反应具有性别特异性，这可能导致性别失衡，而微生物如何缓解这种现状尚不清楚。本研究利用乡土树种杨树的生长土壤，在盐胁迫下，分别接种丛枝菌根真菌（AM），研究不同性别巴山杨根际土壤的生长参数、土壤理化性质的变化，并对不同性别巴山杨根际土壤的微生物群落结构进行比较。采用 qPCR 和 DGGE 联合监测方法，鉴定与盐胁迫和 AM 共生相关的雌雄异株特有微生物群落特征，以明确雌雄异株特有微生物群落对盐胁迫的响应机制。盐胁迫下，雌雄株幼苗生长均受到严重抑制，表现在生长、生物量和养分元素积累受限，尤以雌株更为明显。AM 接种处理缓解了盐胁迫对雌雄株的抑制作用，尤其在盐处理 75 mM 时更为明显。与盐胁迫相比，AM 接种处理对雌雄株土壤理化性质的影响更大。DGGE 结果表明，盐胁迫显著降低了真菌丰富度，而提高了真菌 Simpson 多样性指数，AM 接种处理则表现出相反的作用。结构方程模型（SEM）表明，盐和 AM 接种处理对生物量积累和微生物群落结构的因果关系：盐和 AM 接种处理对基本元素浓度、土壤性质有复杂的影响，进而与生物量积累和微生物群落结构有不同的关系。盐胁迫对巴山杨根际土壤性质和微生物群落结构有负面影响，而 AM 接种则对大多数土壤理化性质和微生物群落状况有积极影响。
