A Previously Undescribed Helotialean Fungus That Is Superabundant in Soil Under Maritime Antarctic Higher Plants.
A Previously Undescribed Helotialean Fungus That Is Superabundant in Soil Under Maritime Antarctic Higher Plants.
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DOI：
10.3389/fmicb.2020.615608
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发表时间：
2020
影响因子：
5.2
通讯作者：
Robinson CH
中科院分区：
文献类型：
--
作者：
Newsham KK;Cox F;Sands CJ;Garnett MH;Magan N;Horrocks CA;Dungait JAJ;Robinson CH
我们报告一个以前未描述的成员Helotiales，是在两个海洋南极岛屿的土壤中的南极发草（Deschampsia anaustica Desv.）的过剩。高通量测序显示，岛上土壤中高达92%的DNA读数和68%的RNA读数都是由真菌引起的。核糖体（r）DNA的大亚基区的测序将真菌接近Pezizellaceae，Porodiplodiaceae和Sclerotiniaceae，与rDNA的内部转录间隔区的分析表明，它具有亲和力，以前未命名的土壤和根真菌从高山，冷温带和低北极地区。这种真菌在距今1000 - 1200年的含碳土壤中最为常见。其DNA和RNA的相对丰度与土壤碳、氮浓度和δ 13 C值呈正相关，而DNA的相对丰度与土壤pH值呈负相关。该菌的一个分离物产生瓶状的瓶梗，具有明显的腹，带有大小为4.5-6（7）× 1.8-2.5 μm的分生孢子，暗示着变形的Chalara。酶学研究表明，该菌株能强烈合成胞外酶酸性磷酸酶，也具有碱性磷酸酶和萘酚-AS-BI-磷酸水解酶活性。生理生态学测量表明，分离物的最佳菌丝生长pH值为4.2-4.5，水势为-0.66 MPa。该分离物是一种嗜冷菌，在−2°C下表现出可测量的菌丝生长，在15°C下表现出最佳菌丝延伸速率，在25°C下表现出可忽略的生长。有人提出，预计本世纪晚些时候在海洋南极洲发生的温度上升将增加真菌的生长速度，并可能从土壤中损失古C。使用全球真菌数据库的分析表明，该真菌存在于所有大陆的寒冷酸性土壤中。我们主张进一步的研究，以确定是否在土壤中过量的D。南极洲其他地方的海洋anapartica，并获得进一步的分离物，使该物种可以正式描述。
We report a previously undescribed member of the Helotiales that is superabundant in soils at two maritime Antarctic islands under Antarctic Hairgrass (Deschampsia antarctica Desv.). High throughput sequencing showed that up to 92% of DNA reads, and 68% of RNA reads, in soils from the islands were accounted for by the fungus. Sequencing of the large subunit region of ribosomal (r)DNA places the fungus close to the Pezizellaceae, Porodiplodiaceae, and Sclerotiniaceae, with analyses of internal transcribed spacer regions of rDNA indicating that it has affinities to previously unnamed soil and root fungi from alpine, cool temperate and Low Arctic regions. The fungus was found to be most frequent in soils containing C aged to 1,000–1,200 years before present. The relative abundances of its DNA and RNA reads were positively associated with soil carbon and nitrogen concentrations and δ13C values, with the relative abundance of its DNA being negatively associated with soil pH value. An isolate of the fungus produces flask-shaped phialides with a pronounced venter bearing masses of conidia measuring 4.5–6(7) × 1.8–2.5 μm, suggestive of anamorphic Chalara. Enzymatic studies indicate that the isolate strongly synthesizes the extracellular enzyme acid phosphatase, and also exhibits alkaline phosphatase and naphthol-AS-BI-phosphohydrolase activities. Ecophysiological measurements indicate optimal hyphal growth of the isolate at a pH of 4.2–4.5 and a water potential of −0.66 MPa. The isolate is a psychrotroph, exhibiting measureable hyphal growth at −2°C, optimal hyphal extension rate at 15°C and negligible growth at 25°C. It is proposed that the rising temperatures that are predicted to occur in maritime Antarctica later this century will increase the growth rate of the fungus, with the potential loss of ancient C from soils. Analyses using the GlobalFungi Database indicate that the fungus is present in cold, acidic soils on all continents. We advocate further studies to identify whether it is superabundant in soils under D. antarctica elsewhere in maritime Antarctica, and for further isolates to be obtained so that the species can be formally described.
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影响因子：
9.4
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