苏打盐碱地丛枝菌根真菌群落结构与多样性特征

Structures and diversity of arbuscular mycorrhizal fungal communities in soda saline-alkali land

摘要:

盐碱地是全球范围内广泛分布的一类退化土壤，其中苏打盐碱地因其盐碱共存的特征治理难度较大，是制约土壤资源有效利用的重要障碍。丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)通过促进养分吸收和增强抗逆性改善植物的生长与存活能力，为苏打盐碱地的改造利用提供潜在途径。目的 探究在苏打盐碱胁迫梯度下AMF群落结构和多样性随胁迫和其他环境因子的变化。方法 采集吉林省长岭县和大安市中受到不同程度苏打盐碱胁迫的土壤样品，包括长有碱蓬(Suaeda glauca)的荒地(pH 10.0-10.5)、无植被覆盖的裸地(pH 9.5-10.0)和胁迫程度不同的玉米(Zea mays L.)农田(pH 8.5-10.0)。利用18S rRNA基因高通量测序方法检测AMF群落结构与多样性。结果 检测到的AMF在属水平上以内养囊霉属(Entrophospora)、斗管囊霉属(Funneliformis)、根孢囊霉属(Rhizoglomus)和多氏囊霉属(Dominikia)为主。AMF相对多度与土壤总碳、总氮、总磷、有效氮显著正相关，与土壤pH、电导率和盐度显著负相关。AMF群落结构与土壤总碳和pH显著相关；AMF香农多样性(α多样性)与土壤全磷含量和盐度呈显著正相关；AMF群落结构离散度(β多样性)与电导率显著负相关；AMF的α多样性和β多样性显著负相关。结论 盐碱胁迫对AMF群落施加了同质性选择，使其群落变小、β多样性降低、α多样性升高、种类组成发生改变。

Abstract:

Saline-alkali land is a common type of degraded soil with wide distribution across the globe. Among all types of saline-alkali land, soda saline-alkali land, characterized by the coexistence of high salinity and alkalinity, is particularly difficult to be managed and represent a major obstacle to the effective utilization of soil resources. Arbuscular mycorrhizal fungi (AMF) enhance plant growth and survival by improving nutrient uptake and increasing stress resistance, offering promising potential for the reclamation and utilization of saline-alkali land.Objective To explore how the structures and diversity of the AMF community vary along a soda saline-alkaline stress gradient in response to stress and other environmental factors.Methods We collected soil samples subjected to varying levels of soda saline-alkaline stress from Changling County and Da’an City in Jilin Province. The sampling sites included Suaeda glauca-covered wildland (pH 10.0-10.5), unvegetated bare land (pH 9.5-10.0), and maize (Zea mays L.) farmlands under varying levels of stress (pH 8.5-10.0). The structures and diversity of AMF communities in these soil samples were analyzed by Illumina-based 18S rRNA gene sequencing.Results AMF communities were predominantly composed of Entrophospora, Funneliformis, Rhizoglomus, and Dominikia. The relative abundance of AMF was significantly positively correlated with soil total carbon, total nitrogen, total phosphorus, and available nitrogen, and it was significantly negatively correlated with soil pH, electrical conductivity, and salt content. The AMF community structure was significantly associated with soil total carbon and pH. The Shannon diversity (alpha diversity) of AMF showed significantly positive correlations with total phosphorus and salt content, while the AMF community structure dispersion (beta diversity) was significantly negatively correlated with electrical conductivity. Moreover, the alpha diversity and beta diversity of AMF had a significantly negative correlation.Conclusion Saline-alkaline stress exerted homogeneous selection on the AMF community, leading to reduced community size, decreased beta diversity, increased alpha diversity, and altered community composition.