Abstract:

A field randomized block design was arranged to investigate the effects of warming and straw application on the composition and diversity of soil fungal community. The compositions at the phylum, class, and order levels and the α and β diversities of soil fungal community in soybean-winter wheat crop fields were determined using high-throughput sequencing. The results showed that the phyla with the highest relative abundance were Ascomycota, Basidiomycota and Zygomycota. The relative abundance of Ascomycota in the WA plots was significantly lower than that in the CK (P=0.023) and SA (P=0.007) plots. There was a marginally significant difference (P=0.063) in the relative abundance of Ascomycota between the WA and WS treatments. Warming reduced the relative abundance of Sordariomycetes, which had the highest relative abundance at the class level, but this effect of warming was offset by straw application. The Hypocreales had the highest relative abundance in the soybean crop field. The phylum and class with the highest relative abundance in the winter wheat crop field were as the same as those in the soybean crop field. There was a significant difference (P=0.047) in the relative abundance of Ascomycota between the CK and WS treatments. There were no significant differences (P>0.05) in the relative abundance of Sordariomycetes and Hypocreales between the CK and WS treatments. The species in the WA plots were significantly lower than those in the WS plots in the winter wheat crop field (P<0.012), and the WA plots had the lowest Shannon and Simpson index values among all the treatments. There were marginally significant differences in the species (P=0.087) and Chao1 index values (P=0.088) between the CK and SA treatments in the winter wheat crop field. Straw application increased the species and the α diversity in the winter wheat crop field. The number of fungal groups at the phylum, class, and order levels in the soybean crop field was obviously higher than that in the winter wheat crop field, indicating that more differences existed between some fungal groups under different warming and straw application treatments in the soybean crop field than in the winter wheat crop field. The soybean crop field had obviously higher species and Chao1 index values than the winter wheat crop field. The Shannon and Simpson index values in the soybean crop field were also higher than those in the winter wheat crop field. The soybean crop field had higher β diversity (weighted Unifrac distance) than the winter wheat crop field, indicating a greater difference in the species between the treatments in the soybean crop field. The N fixation capacity of soybean crop fields provided favorable conditions for the fungal diversity, and some fungal groups in the soybean crop field were more susceptible to temperature increase and straw application than those in the winter wheat crop field.

Key words: fungi, community composition, Ascomycota, α diversity, β diversity

摘要：

为研究增温及秸秆施用对农田土壤真菌群落组成及多样性的影响,设置随机区组田间试验,试验包括对照（CK）、增温（WA）、秸秆施用（SA）、增温及秸秆施用（WS）4个处理,采用高通量测序研究大豆 (Glycine max L.)-冬小麦 (Triticum aestivum L.) 轮作农田土壤真菌门、纲、目水平上的组成及α、β多样性。结果表明,在门水平上,大豆田相对丰度最高的土壤真菌门包括子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、接合菌门（Zygomycota）等,WA处理子囊菌门相对丰度显著低于CK（P=0.023）及SA（P=0.007）处理,且与WS处理存在边缘显著差异（P=0.063）。在纲水平上,增温减少了相对丰度最高的粪壳菌纲（Sordariomycetes）相对丰度,但秸秆施用抵消了增温的这种效应。在目水平上,大豆田相对丰度最高的土壤真菌目为肉座菌目（Hypocreales）。冬小麦田相对丰度最高的真菌门、纲与大豆田相同。冬小麦田CK与WS处理子囊菌门相对丰度之间存在显著差异（P=0.047）,各处理粪壳菌纲、肉座菌目相对丰度之间无显著差异（P>0.10）。大豆田WA处理的真菌物种数显著（P=0.012）小于WS处理,大豆田WA处理Shannon指数和Simpson指数均最小。冬小麦田CK与SA处理物种数（P=0.087）、Chao1指数（P=0.088）均存在边缘显著差异。秸秆施用增加了冬小麦田真菌物种数并使α多样性增大。大豆田土壤真菌门、纲、目水平上存在差异的类群明显比冬小麦田多,说明大豆田某些真菌类群受增温及秸秆施用处理的影响相对更大。大豆田土壤真菌比冬小麦田具有更大的α多样性,其物种数和Chao1指数远大于冬小麦田,且具有更大的Shannon指数和Simpson指数;大豆田土壤真菌β多样性（加权单比例距离）总体上大于冬小麦田,前者不同处理之间的物种差异性相对更大。大豆田的自然固氮能力为真菌类群的多样性提供了条件,其中的某些类群更易受增温及秸秆施用影响。

关键词: 真菌, 群落组成, 子囊菌门, α多样性, β多样性