Lang Ming, Zou Wenxin, Chen Xiuxiu, Zou Chunqin, Zhang Wei, Deng Yan, Zhu Feng, Yu Peng, Chen Xinping
College of Resources and Environment, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China.
Front Microbiol. 2021 Jan 14;11:605955. doi: 10.3389/fmicb.2020.605955. eCollection 2020.
Microbes associated with phosphorus (P) cycling are intrinsic to soil P transformation and availability for plant use but are also influenced by the application of P fertilizer. Nevertheless, the variability in soil P in the field means that integrative analyses of soil P cycling, microbial composition, and microbial functional genes related to P cycling remain very challenging. In the present study in the North China Plain, we subjected the bacterial and fungal communities to amplicon sequencing analysis and characterized the alkaline phosphatase ( encoding bacterial alkaline phosphatase in a long-term field experiment (10 years) with six mineral P fertilization rates up to 200 kg P ha. Long-term P fertilization increased soil available P, inorganic P, and total P, while soil organic P increased until the applied P rate reached 25 kg ha and then decreased. The fungal alpha-diversity decreased as P rate increased, while there were no significant effects on bacterial alpha-diversity. Community compositions of bacteria and fungi were significantly affected by P rates at order and family levels. The number of keystone taxa decreased from 10 to 3 OTUs under increasing P rates from 0 to 200 kg ha. The gene copy numbers of the biomarker of the alkaline phosphatase was higher at moderate P rates (25 and 50 kg ha) than at low (0 and 12.5 kg ha) and high (100 and 200 kg ha) rates of P fertilization, and was positively correlated with soil organic P concentration. One of the keystone taxa named BacOTU3771 belonging to Xanthomonadales was positively correlated with potential functional genes encoding enzymes such as glycerophosphoryl diester phosphodiesterase, acid phosphatase and negatively correlated with guinoprotein glucose dehydrogenase. Altogether, the results show the systematic effect of P gradient fertilization on P forms, the microbial community structure, keystone taxa, and functional genes associated with P cycling and highlight the potential of moderate rates of P fertilization to maintain microbial community composition, specific taxa, and levels of functional genes to achieve and sustain soil health.
与磷（P）循环相关的微生物是土壤磷转化和植物可利用性的内在因素，但也受到磷肥施用的影响。然而，田间土壤磷的变异性意味着对土壤磷循环、微生物组成以及与磷循环相关的微生物功能基因进行综合分析仍然极具挑战性。在华北平原的本研究中，我们对细菌和真菌群落进行了扩增子测序分析，并在一项长达10年的田间试验中，以高达200 kg P ha的六种矿物磷肥施用量，对碱性磷酸酶（编码细菌碱性磷酸酶）进行了表征。长期施磷增加了土壤有效磷、无机磷和总磷，而土壤有机磷在施磷量达到25 kg ha之前增加，之后下降。真菌的α多样性随施磷量增加而降低，而对细菌的α多样性没有显著影响。细菌和真菌的群落组成在目和科水平上受到施磷量的显著影响。随着施磷量从0增加到200 kg ha，关键分类单元的数量从10个减少到3个OTU。碱性磷酸酶生物标志物的基因拷贝数在中等施磷量（25和50 kg ha）时高于低（0和12.5 kg ha）和高（100和200 kg ha）施磷量，且与土壤有机磷浓度呈正相关。一个属于黄单胞菌目的关键分类单元BacOTU3771与编码甘油磷酸二酯磷酸二酯酶、酸性磷酸酶等酶的潜在功能基因呈正相关，与醌蛋白葡萄糖脱氢酶呈负相关。总之，结果表明磷梯度施肥对磷形态、微生物群落结构、关键分类单元以及与磷循环相关的功能基因具有系统性影响，并突出了适度施磷量在维持微生物群落组成、特定分类单元和功能基因水平以实现和维持土壤健康方面的潜力。
