Physiological and transcriptional responses of the ectomycorrhizal fungus Cenococcum geophilum to salt stress
Physiological and transcriptional responses of the ectomycorrhizal fungus Cenococcum geophilum to salt stress
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DOI：
10.1007/s00572-022-01078-1
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发表时间：
2022-05-11
期刊：
影响因子：
3.9
通讯作者：
Lian, Chunlan
中科院分区：
文献类型：
--
作者：
Li, Jiali;Li, Chaofeng;Lian, Chunlan
外生菌根（ECM）真菌提高了宿主植物对非生物和生物胁迫的耐受性。土生空球藻（Cenococcum geophilum，Cg）是世界上最常见的ECM真菌之一，并且通常生长在盐水环境中。然而，该真菌耐盐的生理和分子机制在很大程度上是未知的。本研究以采自不同生态地理区的12个菌株为材料，研究了盐胁迫条件下，白腐病菌的耐盐机制。根据其在0、50、125、250和500 mM NaCl浓度下的体外菌丝生长情况，将菌株分为4组（盐敏感、中度耐盐、耐盐和嗜盐）。因此，测定了菌丝体的Na、Ca、P和K浓度以及培养液的pH。与耐盐菌株相比，用250 mM NaCl处理显著增加了盐敏感菌株的钠浓度，降低了盐敏感菌株的钾浓度。进行RNA测序和qRT-PCR分析以鉴定参与跨膜转运和氧化还原酶活性途径的差异表达基因（DEG）。通过对菌丝过氧化氢浓度、过氧化物酶和超氧化物歧化酶活性的测定，发现盐敏感菌株比耐盐菌株对活性氧的积累和清除更活跃。结果为RNA-seq和qRT-PCR分析提供了功能验证。本研究为深入了解Cg菌株的盐胁迫反应提供了新的视角，并为阐明ECM真菌的耐盐机制奠定了基础。
Ectomycorrhizal (ECM) fungi improve the host plant's tolerance to abiotic and biotic stresses. Cenococcum geophilum (Cg) is among the most common ECM fungi worldwide and often grows in saline environments. However, the physiological and molecular mechanisms of salt tolerance in this fungus are largely unknown. In the present study, 12 isolates collected from different ecogeographic regions were used to investigate the mechanism of salt tolerance of Cg. The isolates were classified into four groups (salt-sensitive, moderately salt-tolerant, salt-tolerant, and halophilic) based on their in vitro mycelial growth under 0, 50, 125, 250, and 500 mM NaCl concentrations. Hence, the Na, Ca, P, and K concentrations of mycelia and the pH of the culture solution were determined. Compared with salt-tolerant isolates, treatment with 250 mM NaCl significantly increased the sodium concentration and decreased the potassium concentration of salt-sensitive isolates. RNA-sequencing and qRT-PCR analysis were conducted to identify differentially expressed genes (DEGs) involved in transmembrane transport and oxidoreductase activity pathways. The hydrogen peroxide concentration and activities of peroxidase and superoxide dismutase in mycelia were determined, and the accumulation and scavenging of reactive oxygen species in the salt-sensitive isolates were more active than those in the salt-tolerant isolates. The results supply functional validations to RNA-seq and qRT-PCR analysis. This study provides novel insights into the salt-stress response of Cg isolates and provides a foundation for elucidation of the salt-tolerance mechanism of ECM fungi.