Diverse Plant-Associated Pleosporalean Fungi from Saline Areas: Ecological Tolerance and Nitrogen-Status Dependent Effects on Plant Growth.
Diverse Plant-Associated Pleosporalean Fungi from Saline Areas: Ecological Tolerance and Nitrogen-Status Dependent Effects on Plant Growth.
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来自盐碱地的多种植物相关的前孢菌：生态耐受性和氮状态对植物生长的依赖性影响
DOI：
10.3389/fmicb.2017.00158
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发表时间：
2017
影响因子：
5.2
通讯作者：
Yuan Z
中科院分区：
文献类型：
--
作者：
Qin Y;Pan X;Kubicek C;Druzhinina I;Chenthamara K;Labbé J;Yuan Z
与菌根共生菌类似，根际和内生真菌也被认为是宿主适合度的主动调节剂（例如，营养和胁迫耐受性）。尽管在选定的模型系统中进行了大量工作，但人们普遍对植物相关真菌在极端条件下的栖息地中的结构以及它们在多大程度上有助于改善植物性能知之甚少。在这里，我们调查了根和种子相关的真菌在中国的盐生植物生长的地区的社区组成，并发现，多孢纲类群（子囊菌门）是最常见的样品之间分离。根据多位点数据（部分18 S rDNA、28 S rDNA和转录延伸因子1-α），共筛选出27个代表性菌株，将其分为7个科，其中一个分支可能代表一个新的谱系。通过施加温度、pH、离子和渗透条件对真菌分离物进行生长响应测定。真菌有广泛的pH值的耐受性，而大多数菌株表现出不同程度的敏感性增加浓度的盐或山梨醇。随后的植物-真菌共培养试验表明，在无机氮的存在下，大多数分离物对植物生长仅产生中性甚至不利影响。有趣的是，当提供有机氮源时，大多数分离物促进植物生长，特别是地上生物量。大多数真菌更喜欢有机氮，而不是无机氮，这表明这些真菌可以很容易地将有机氮矿化为无机氮。显微镜下观察发现，几个菌株可以成功地殖民根和形成黑化菌丝和/或微菌核样结构的皮层细胞内，这表明系统发育分配为暗分隔内生菌。这项工作提供了一个更好的了解植物和多孢真菌之间的共生关系，并为利用这种真菌群有益于植物生产的初步证据。
Similar to mycorrhizal mutualists, the rhizospheric and endophytic fungi are also considered to act as active regulators of host fitness (e.g., nutrition and stress tolerance). Despite considerable work in selected model systems, it is generally poorly understood how plant-associated fungi are structured in habitats with extreme conditions and to what extent they contribute to improved plant performance. Here, we investigate the community composition of root and seed-associated fungi from six halophytes growing in saline areas of China, and found that the pleosporalean taxa (Ascomycota) were most frequently isolated across samples. A total of twenty-seven representative isolates were selected for construction of the phylogeny based on the multi-locus data (partial 18S rDNA, 28S rDNA, and transcription elongation factor 1-α), which classified them into seven families, one clade potentially representing a novel lineage. Fungal isolates were subjected to growth response assays by imposing temperature, pH, ionic and osmotic conditions. The fungi had a wide pH tolerance, while most isolates showed a variable degree of sensitivity to increasing concentration of either salt or sorbitol. Subsequent plant–fungal co-culture assays indicated that most isolates had only neutral or even adverse effects on plant growth in the presence of inorganic nitrogen. Interestingly, when provided with organic nitrogen sources the majority of the isolates enhanced plant growth especially aboveground biomass. Most of the fungi preferred organic nitrogen over its inorganic counterpart, suggesting that these fungi can readily mineralize organic nitrogen into inorganic nitrogen. Microscopy revealed that several isolates can successfully colonize roots and form melanized hyphae and/or microsclerotia-like structures within cortical cells suggesting a phylogenetic assignment as dark septate endophytes. This work provides a better understanding of the symbiotic relationship between plants and pleosporalean fungi, and initial evidence for the use of this fungal group in benefiting plant production.