Arbuscular mycorrhizal fungi influence decomposition and the associated soil microbial community under different soil phosphorus availability.
Arbuscular mycorrhizal fungi influence decomposition and the associated soil microbial community under different soil phosphorus availability.
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DOI：
10.1016/j.soilbio.2018.02.010
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发表时间：
2018-05
影响因子：
9.7
通讯作者：
Jing Xu;Shijun Liu;Shurui Song;Hanling Guo;Jianjun Tang;J. Yong;Yuandan Ma;Xin Chen
中科院分区：
文献类型：
--
作者：
Jing Xu;Shijun Liu;Shurui Song;Hanling Guo;Jianjun Tang;J. Yong;Yuandan Ma;Xin Chen
尽管人们普遍认识到丛枝菌根真菌(AMF)可以影响有机物质的分解，但其潜在的机制仍不清楚。在这里，我们研究了AMF是否通过养分获取影响分解和改变相关的土壤细菌和真菌群落，以及这种影响是否被土壤磷(P)水平所改变。以元宝紫花苜蓿为寄主，在不施或不施AM菌剂的条件下，设置两个土壤磷水平(4和24 mg kg−1)，进行盆栽试验。菌丝内生网袋(不包括根部，但不包括菌丝或其他微生物)被用来测量AMF菌丝对分解的影响。有机底物采用15N：13C稳定同位素双标记玉米叶片。通过对部分16S rRNA及其基因进行测序，获得细菌和真菌群落。结果表明，在土壤磷有效性较低的情况下，施AM肥的网袋中残留有机质的15N和13C含量显着低于不施AMF的处理。然而，在土壤磷有效性较高的情况下，AMF处理与非AMF处理之间残留的15N含量没有显著差异，而AMF处理的残留13C含量高于非AMF处理。AMF菌丝在低磷条件下的菌根定植水平和15N从有机质向寄主的转运水平高于高磷条件下的菌根定植水平，表明土壤低磷条件下寄主可以通过AM从有机质中获取更多的养分。在这两个土壤磷水平上，AMF都改变了细菌和真菌群落的组成。细菌群落的丰富度和多样性较高，磷的有效性较低，特别是糖化菌和硝化螺旋藻。对于真菌群落而言，在低磷条件下，丛枝菌根真菌增加了群落的丰富度，但没有增加群落的多样性。综上所述，我们发现AMF为寄主从有机质中获取养分，影响分解和改变细菌和真菌群落，并且这些影响受到土壤P有效性的调节。
Despite the general appreciation that arbuscular mycorrhizal fungi (AMF) can influence decomposition of organic materials, the underlying mechanisms remain unclear. Here we investigated whether AMF influence decomposition and change the associated soil bacterial and fungal communities through nutrient acquisition and whether this effect is altered by the level of soil phosphorus (P). We conducted a pot experiment usingMedicago truncatulaas host plant without or with AMF (a mixture of six species) and with two levels of soil P (4 and 24 mg kg−1). Hyphal-ingrowth mesh bags (which excluded roots but not hyphae or other microbes) were used to measure the effect of AMF hyphae on decomposition. Maize leaves dual-labeled with15N:13C stable isotopes were used as the organic substrate. Bacterial and fungal communities were accessed via sequencing of partial 16S rRNA and ITS genes. The results showed the15N and13C content of the organic matter remaining in the mesh bags under low soil P availability were significantly lower in the treatment with AMF than without AMF. Under high soil P availability, however, no significant difference of15N content remaining was found between AMF and non-AMF treatments, while13C content remaining was higher in AMF than in non-AMF treatment. Levels of mycorrhizal colonization and15N transport from organic matter to the host by AMF hyphae were higher at low P availability than at high P availability, suggesting that the host can acquire more nutrients through the AM from organic matter when soil P availability was low. The composition of bacterial and fungal communities were altered by AMF at both soil P levels. For bacterial community, the richness and diversity were higher with low P availability, especially for the phyla Saccharibacteria and Nitrospirae. For fungal community, AMF increased the richness but not the diversity under low P availability. Together, we show that AMF acquire nutrients from organic matter for host, influence decomposition and alter the bacterial and fungal communities, and that these effects were modulated by the soil P availability.