Survey of Soil Fungal Communities in Strawberry Fields by Illumina Amplicon Sequencing

Soil fungal pathogens are the most common cause of diseases in commercial strawberry crops worldwide. Since simultaneous infections by different pathogens can severely damage the crop, understanding the associated fungal communities can be helpful to mitigate crop loss. Herein, we used Illumina metabarcoding to assess the structure of fungal communities in five strawberry production areas in Estonia. Our analysis revealed 990 to 1430 operational taxonomic units (OTUs) per soil sample (pools of eight soil samples per production area). Based on our analyses, Ascomycota (55.5%) and Basidiomycota (25.0%) were the most OTUs-rich. Amongst the 24 most abundant OTUs, Geomyces, Rhodotorula, Verticillium and Microdochium were the most abundant genera, which were found across nearly all the soil samples. The OTUs were also clustered into three distinct groups, corresponding to different functional guilds of fungi. In addition, Fusarium solani, V. dahliae, Rhizoctonia solani and Colletotrichum truncatum were enormously abundant in the fields with disease symptoms, whereas arbuscular mycorrhizal fungi especially Rhizophagus irregularis were considerably more abundant in the fields with healthy plants. These findings provide support that mycorrhizal fungi may play an important role in suppressing pathogens. Our study for the first time shows the usefulness of Illumina technology in surveying the communities of soil fungi in strawberry fields effectively, which may improve available disease management strategies against strawberry diseases.     

Effect of Geogenic Lead on Fungal and Collembolan Communities in Garden Topsoil

Geogenic lead (Pb) is considered to be less bioavailable than anthropogenic Pb and exerts less effect on the soil fauna. However, Pb contamination in vegetables has been reported in the case of geogenic anomalies, even at moderate concentrations (around 170 mg kg^–1). In this study, we investigated collembolan communities using both taxonomic- and trait-based approaches and observed fungal communities to assess the effects of a moderate geogenic Pb anomaly on collembolans and fungi in an urban vegetable garden soil. Results indicated that geogenic Pb indeed modified fungi communities and altered the functional structure of collembolan communities in garden soils. Although geogenic Pb presented low bioavailability, it affected soil fauna and vegetables similar to anthropogenic Pb.     

苯系物(BTEX)长期污染对土壤和地下水微生物群落及代谢潜能的影响

苯、甲苯、乙苯和二甲苯统称为苯系物(BTEX)，是化工污染场地检出率最高的芳香族有机污染物。为研究BTEX长期污染对土壤和地下水微生物群落结构和代谢潜能的影响，采集了江苏省某搬迁化工厂的浅层土、地下水和深层土样品，利用16S rRNA基因扩增子测序和宏基因组测序技术对BTEX长期污染场地展开分析。结果表明：相比较未受污染的土壤样品，长期BTEX污染显著改变了微生物群落结构和多样性，其中以变形菌门改变最为显著。共现性网络分析表明，污染场地中随着样品取样深度的增加，微生物网络复杂性和群落稳定性降低。BTEX代谢功能基因注释表明，地下水样品中污染物代谢基因丰度和多样性更高，并且在地下水和浅层土中同时存在完整的好氧降解途径，但在地下水中厌氧降解基因的丰度更高。BTEX降解途径中benABC和bcrCBAD基因簇在浅层土中更完整，但通过构建BTEX开环的关键基因bamA的系统发育树表明，地下水中可能存在新的BTEX开环基因。这些结果证明BTEX长期污染的不同生境中存在高度多样的微生物群落与降解途径，为相关污染场地的微生物修复提供了科学依据。     

土壤真菌群落和潜在功能对施加外源Bt毒素的响应

【目的】转Bt基因植物和Bt菌生物农药释放的Bt毒素是一类具有生物毒性的潜在环境外源污染物，Bt毒素环境行为和生态效应是转基因植物和植物用转基因微生物安全风险评价的重要内容，但是外源Bt毒素对土壤真菌群落和潜在功能的影响还不清楚。【结果】本研究发现，Bt毒素施加量和培养时间均可以显著影响土壤真菌群落组成，且随着Bt毒素施加量增加和土壤培养时间延长，土壤真菌群落差异性逐渐变大。施加Bt毒素提高了土壤真菌群落香农指数和关联网络的负相关性比例及模块数，因而没有对土壤真菌群落的多样性和稳定性产生负面影响。【结论】上述结果表明，评估Bt毒素的环境行为及微生态效应要关注Bt毒素施加量及其长期影响。随着Bt毒素施加量增加，Phymatotrichopsis、Homalogastra、Geosmithia和Apiotrichum等真菌以及参与蛋白质降解、碳素代谢和磷素代谢的功能基因编码酶相对丰度显著升高，推测上述真菌物种和潜在功能参与了Bt毒素在土壤中的降解和转化过程。研究结果为转Bt基因植物、Bt重组菌生物农药以及Bt毒素的生态安全风险评价提供了科学参考和理论依据。     

石油污染土壤中细菌的分离筛选

从辽河油田石油污染土壤中分离筛选得到59株细菌,并对其石油降解能力进行了研究。结果表明,大多数细菌具有较高的石油降解能力及脂酶活性,其中B-4、B-5、B-46、B-47四株细菌的石油降解率分别达到52.1%、55.4%、51.6%、59.3%。经初步鉴定B-5、B-46、B-47均属于微球菌属(Micrococcusspp.),B-4属于节杆菌属(Arthrobactersp.)。     

铜、锌污染梯度对自然林地和农田土壤线虫群落的影响

为从污染程度的角度探索土壤线虫多样性与群落稳定性的关系,以重金属铜和锌为扰动因子,设置不同程度的胁迫水平,通过恒温培养试验对比高生物多样性的自然林地和低生物多样性的农田土壤线虫群落对重金属胁迫的响应。结果表明:自然林地土壤线虫数量随Cu和Zn的添加浓度升高而降低;农田土壤线虫总数呈现低浓度扰动条件下降低,中、高浓度又反弹的现象。占绝对优势的食细菌线虫数量变化规律与线虫总数相近;自然林地中捕食杂食性线虫仅在添加高浓度Zn处理有所减少,而在农田土壤中,中、高浓度Cu,以及低浓度Zn处理均呈现出显著的抑制效应。重金属梯度对自然林地线虫多样性无显著影响,但是降低了农田线虫的香农指数,提高了优势度。总体上,Cu和Zn扰动对自然林地线虫的影响主要表现在数量上,对农田线虫的影响更多体现在群落结构、多样性和生态指数上。就污染程度以及生物群落结构的角度而言,高多样性的自然林地线虫群落对Cu和Zn污染的抵抗力更强。     

The Structure of Bacterial and Fungal Communities in the Rhizosphere and Root-Free Loci of Gray Forest Soil

Eurasian Soil Science - The taxonomic composition, abundance, and diversity of bacterial and fungal communities in the rhizosphere loci and bulk mass of the gray forest soil (Eutric Retisol...     

秸秆生物质炭对根际土壤细菌-真菌群落分子生态网络的影响

根际细菌-真菌群落的互作关系对于土壤养分转化有重要意义。为研究施加生物质炭对根际土壤细菌-真菌之间相互作用的影响,通过盆栽试验,比较未施加生物质炭的对照和施加2%生物质炭处理条件下,黑麦草根际细菌-真菌群落间的互作网络及影响因素。结果表明,施加生物质炭后的细菌-真菌群落之间的互作网络具有更复杂的联系,节点数和互作关系增加,细菌内部以及细菌与真菌之间的种间积极作用显著增强(P0.05);模块化分析对照和处理下的互作网络,均发现存在两个具有高度互连节点的模块化结构。网络中起到关键连接作用的类群在对照中为细菌中的孙修勤菌(Sunxiuqinia)和真菌中的毕赤酵母(Pichia),施加生物质炭处理后为细菌中的黄杆菌(Flavobacterium)。Mantel检验分析表明,施加生物质炭处理后土壤pH(r=0.385,P=0.003)和土壤铵态氮(r=0.501,P=0.003)对细菌-真菌群落相互作用的影响显著增强。     

The Compostable Plastic Poly(lactic) Acid Causes a Temporal Shift in Fungal Communities in Maturing Compost

The compostable biopolymer, poly(lactic) acid (PLA), is increasingly being used as an alternative to conventional plastics for short shelf-life products, disposable bags and packaging, and in agriculture. Despite the increase in the amount of PLA entering composting systems, few studies have examined the impact of PLA degradation on the compost microbial community. Thermophilic fungi play an import role in the composting process as they secrete hydrolytic enzymes capable of breaking down an array of complex natural polymers. In this study, the impact of PLA hydrolysis on the compost fungal community was examined by terminal restriction fragment length polymorphism and 454 sequencing. At 25°C, the effect of PLA on the surrounding compost community was relatively small and no physical changes were observed to the PLA films. However, when incubated at 50°C, where physical disintegration of PLA was occurring, a clear divergence between the compost populations in the presence and absence of PLA was evident after 2 months but became closer to the population in the absence of PLA after 4 months indicating that, after causing an initial perturbation after 2 months, the population began to return to that seen in the absence of PLA. The only exception was in the population containing 50% (w/w) PLA film, which remained divergent after 4 months and was associated with a marked acidification of the compost. Thus, 454-pyrosequencing revealed that the presence of PLA caused a strong selection for a Thermomyces sp. that was present only at low abundance in the absence of PLA.     

LED红蓝光对不同品种水培生菜的影响效果对比

选取9个不同叶色和叶形的生菜品种,以红蓝光比为7︰1的复合光（RBL）为光源,在植物工厂内对比白光（WL）进行试验,以探究红蓝复合光（RBL）对不同品种生菜（Lactuca sativa L.）的响应差异性及影响效果。结果表明,相比于白光（WL）处理,红蓝光（RBL）促进了绿色散叶生菜品种的株高相对生长速率（P＜0.05）,但是抑制了其长势过旺;降低了紫色生菜品种后期叶绿素含量;提高了半结球和散叶生菜品种的净光合速率、蒸腾速率和气孔导度（P＜0.05）;抑制了所有品种生菜PSⅡ的最大光化学效率;提高了散叶生菜品种的ETR值（P＜0.05）;提高了半结球生菜的可溶性固形物含量和可溶性糖含量（P＜0.05）;提高了绿色散生生菜品种的维生素C含量、产量和干物率（P＜0.05）。总之,红蓝光（RBL）对不同品种生菜生长发育及光合荧光特性的影响差异性主要与叶片离散程度相关,对绿色生菜品种品质和产量的提升效果普遍优于紫色生菜品种。     

重金属污染土壤的植物强化修复研究进展

随着工农业生产的快速发展,土壤重金属污染日益严重,土壤重金属污染的高效快速修复技术备受关注。在各种土壤重金属污染修复技术中,植物修复技术因其清洁、简单、高效、低消耗等优点,得到人们的认可,具有良好的发展前景。论文综述了土壤重金属污染来源及现状,植物修复技术的基本原理及特点,植物强化修复技术的研究进展,分析了当前植物强化修复技术中存在的问题,并指明了植物强化修复技术的发展方向,以期为土壤重金属污染的快速、绿色修复提供理论依据。     

青海湖防沙工程措施区土壤水分及入渗特征初步研究

选取青海湖沙区(克土和湖东种羊场)的草方格沙障,主要研究防沙措施的实施对该地区沙土物理性质的影响,采用烘干法和张力入渗仪对其土壤重量含水率及饱和导水率进行了测定。研究结果表明:克土和湖东种羊场的土壤含水率随深度变化都基本符合先增加后下降的趋势;土壤饱和导水率在克土区表现为半流动沙丘>丘间低地>坡底草方格>封沙育草区,湖东种羊场表现为:迎风坡中部草方格>坡底草方格。坡底沙土的入渗较迎风坡坡中部慢,主要与土壤粒度和含水率有关。粗砂含量较高、土壤水分较低的土壤表层渗透较快,而植被盖度较高并且有结皮的土壤表层渗透较慢。     

原料差异对厌氧消化微生物群落的影响

以餐厨垃圾、果蔬垃圾、麦秸3种不同原料分别进行厌氧消化,研究了各反应器在最佳运行条件下的消化特性和微生物群落组成。结果表明：VS产气率由高到低依次为餐厨垃圾（756.4mL·g-1VS-1）、麦秸（696.5mL·g-1VS-1）和果蔬垃圾（433.5mL·g-1VS-1）,甲烷含量在51.5%～55.1%之间,利用PCR-DGGE技术系统地分析了不同原料消化系统内细菌和古菌的群落结构构成及差异。结果表明,虽然3组样品中细菌和古菌的群落存在相同的优势微生物,但其数量和群落结构差异也较为明显,细菌中以拟杆菌（Bacteroidetes）以及古菌中甲烷鬃菌属（Methanosaeta）和甲烷螺菌属（Methanospirillum）均为样品共有的优势微生物。     

The Influence of Heating Mains on Yeast Communities in Urban Soils

The number and species diversity of yeasts in urban soils (urbanozems) affected by heating mains and in epiphytic yeast complexes of grasses growing above them were studied. The number of yeasts in the soil reached 10³–10⁴ CFU/g; on the plants, 10⁷ CFU/g. Significant (by an order of magnitude) increase in the total number of soil yeasts in the zone of heating mains in comparison with the surrounding soil was found in winter period. Overall, 25 species of yeasts were isolated in our study. Yeast community of studied urbanozems was dominated by the Candida sake, an eurybiont of the temperate zone and other natural ecotopes with relatively low temperatures, but its share was minimal in the zone of heating mains. In general, the structure of soil and epiphytic yeast complexes in the zones of heating mains differed from that in the surrounding area by higher species diversity and a lower share of pigmented species among the epiphytic yeasts. The study demonstrated that the number and species structure of soil yeast communities in urban soils change significantly under the influence of the temperature factor and acquire a mosaic distribution pattern.     

氧化钙改性坡缕石对水稻土中Cd污染的钝化效果研究

在钝化实验和盆栽实验中利用土壤理化性质、Cd形态分布、有效态Cd、以及玉米幼苗生长等因素来分析5种比例氧化钙改性坡缕石(1∶1、2∶1、3∶1、4∶1和5∶1,质量比)的施加对水稻土中Cd污染的钝化效果.结果表明:氧化钙改性坡缕石可以显著提高土壤pH、阳离子交换量和电导率.与对照相比,5种氧化钙改性坡缕石使DTPA提取...     

The Dynamics of Soil Microbial Communities on Different Timescales: A Review

Eurasian Soil Science - Soil microbial communities are subjected to significant changes over time. The most rapid changes caused by temperature and soil moisture alternations or the by the inflow...     

含油污泥的堆肥处理对微生物群落结构的影响

采用堆肥方法处理含油污泥,评价堆肥处理对含油污泥中石油烃的去除效果,并采用Biolog方法和构建16SrRNA基因克隆文库的方法对处理过程中微生物碳源利用特征和微生物群落结构进行了研究。结果表明,含油污泥经过90d的堆肥处理,石油烃降解率达53.3%±9.5%,显著高于对照处理。堆肥处理可以显著促进石油烃降解,是一种处理含油污泥的有效措施。Biolog分析结果表明,堆肥处理的孔的平均颜色变化率（AWCD）显著高于对照处理,堆肥处理提高了土壤微生物代谢活性。主成分分析结果表明,对照处理和堆肥处理的微生物碳源利用特征明显不同,堆肥处理改变了含油污泥中微生物的代谢功能特征。对照处理和堆肥处理的16SrRNA基因克隆文库之间存在显著差异,对照处理的优势类群是γ-Proteobacteria,堆肥处理的优势类群是Bacteroidetes,堆肥处理显著改变了含油污泥中的微生物群落结构。Marinobacter和Alcanivorax是对照处理中的优势菌,可能与石油烃的自然降解过程有关,而Pusillimonas和Agrobacterium可能对堆肥处理中石油烃的降解起一定作用。     

土壤重金属污染现状与修复技术研究进展

阐述了土壤重金属污染物的来源和重金属污染土壤修复技术研究现状,分析了各种修复技术的优缺点、实用性与发展动态,为土壤重金属污染综合治理与修复提出了新的思路。     

油枯对镉污染土壤的钝化研究

为了研究油枯对镉(Cd)污染土壤的钝化效果,以油枯为外源添加物(质量比:1%、2%、3%、4%、5%),模拟田间条件在塑料桶中进行为期45 d的培养,对镉污染土壤中Cd形态分布特征、DTPA提取态Cd(DTPA-Cd)含量、pH、有机质含量进行分析。结果表明,添加油枯可显著降低镉污染土壤中可交换态镉(Ex-Cd)的比例,提高碳酸盐结合态镉(Cb-Cd)、铁锰氧化物结合态镉(Fe-Mnb-Cd)以及有机质及硫化物晶格态镉(OMb-Cd)的比例,而残渣晶格结合态镉(RLb-Cd)变化不明显。添加油枯显著降低镉污染土壤中DTPA-Cd含量,降幅最高可达49%。镉污染土壤p H值维持在6.0左右,1%~4%添加处理中土壤pH波动幅度较大;而5%添加处理的土壤pH波动幅度小。添加油枯均能显著提高镉污染土壤中有机质含量。由此可见,油枯对镉污染土壤有较好的钝化效果,这为重金属污染土壤的修复和农业废弃物的循环利用提供了参考。     

Effect of Castor Oil on Soil Erosion by Water

Soils from six different regions of the State of Uttar Pradesh, India, were treated with 1% and 2% concentrations of castor oil and incubated for 15 days and 30 days time. The erosion coefficients of natural as well as treated soils were determined with a simple laboratory erosion apparatus. The castor oil was found to be highly effective in reducing soil erosion. It was more effective in light texture soils with reduction in erosion coefficients to the extent of 88 70. Heavy textured soils also registered good reduction in erosion coefficient, to the extent of 20 %. The castor oil was effective in both the concentrations and both the incubation periods. Similarly, it was effective at all the four slope levels viz. 1, 2, 4 and 8%. The castor oil has been found much superior than cellulose and protein as far as their capability to check soil erosion is concerned.