摘要
【目的】探究有机培肥条件下土壤中含碱性磷酸酶基因(phoD)细菌的群落结构、网络复杂度及稳定性特征,揭示其对微生物介导的土壤磷素转化和有效性的影响。【方法】试验依托四川雅安13年长期定位试验点的玉米体系设置3个无机磷肥处理,分别为0、75、150 kg/hm^(2)(P0、P1和P2)。2018年在此基础上开展裂区实验,设置有机培肥处理,无机肥用量减少30%同时添加猪粪(P0+M、70%P1+M、70%P2+M)。运用高通量测序技术和生物学分析方法测定含phoD基因细菌的群落结构特征,揭示不同供磷水平下有机培肥对土壤含phoD基因细菌群落的影响及其介导的土壤有效磷的调控作用。【结果】随着供磷水平增加,无机肥和有机培肥处理均显著提高了土壤有机质(soil organic matter,SOM)、速效磷(olsen P)和有机磷(organophosphorus,Po)含量,显著降低了土壤pH。供磷水平和有机培肥显著改变了含phoD细菌的群落组成和网络特征。其中,低磷水平(P0、P0+M)下伊卡慢生根瘤菌(Bradyrhizobium icense)为优势物种和指示物种,其相对丰度随施磷量增加显著降低。添加磷后(P1、P2、70%P1+M和70%P2+M),有效慢生根瘤菌(Bradyrhizobium diazoefficiens)和解多聚物浅粉不完全光合杆菌(Roseateles depolymerans)为优势物种,其相对丰度随施磷量增加显著增加。同时,有机培肥处理条件下3个优势物种的相对丰度均高于对应无机磷处理。此外,有机培肥处理的网络节点和连接数量均高于对应无机磷处理。随机森林模型结果显示,优势类群中的Bradyrhizobium icens是土壤速效磷最强的预测因子。未去除优势物种时含phoD基因细菌群落网络稳定性无显著差异;然而,去除优势物种后各处理含phoD基因细菌群落网络稳定性均显著下降。【结论】有机培肥在不同供磷水平下提高了含phoD基因细菌群落中优势物种的相对丰度,增加了含phoD基因细菌网络的复杂度,从而增强了含phoD基因细菌群落的网络稳定性,影响了土壤中磷素的有效性。
[Objective]To investigate the community structure,network complexity,and stability of soil bacteria harboring the alkaline phosphatase gene(phoD)under the application of organic amendments,elucidating their regulatory mechanisms in microbially mediated soil phosphorus(P)transformation and availability.[Methods]We conducted the experiment within a 13-year longterm maize field trial located in Ya’an,Sichuan.The experiment comprised three mineral P fertilizer treatments:0,75,and 150 kg/hm^(2)(designated as P0,P1,and P2,respectively).In 2018,a split-plot design was implemented with organic amendment treatments,where mineral P application was reduced by 30%and supplemented with pig manure(P0+M,70%P1+M,and 70%P2+M treatments).The phoD-harboring bacterial community structure was characterized by highthroughput sequencing and bioinformatic analyses,which revealed the effects of organic amendments with varying P supply levels on phoD-harboring bacterial communities and their regulation of soil available P.[Results]As the P supply level increased,both mineral and organic amendments significantly increased the content of soil organic matter(SOM),Olsen-P,and organic P(Po),while significantly decreasing soil pH.P levels and organic amendments markedly altered the community composition and network characteristics of phoD-harboring bacteria.Under low-P conditions(P0,P0+M),Bradyrhizobium icense emerged as both the dominant and indicator species,with its relative abundance decreasing significantly as P application increased.Under P-amended treatments(P1,P2,70%P1+M,and 70%P2+M),Bradyrhizobium diazoefficiens and Roseateles depolymerans became the predominant species,exhibiting significant increases in relative abundance with higher P inputs.Notably,the relative abundance of all the three dominant species under the application of organic amendments was higher than that in corresponding inorganic P treatments.Furthermore,organic amendments increased the network nodes and connectivity links compared with corresponding mineral P treatments.Random forest analysis further identified B.icense as the strongest predictor of soil available P.The stability of phoDharboring bacterial networks showed no significant difference across treatments.However,after the removal of dominant species,the network stability declined significantly in all treatments.[Conclusion]Organic amendments increase the relative abundance of dominant species within the phoD-harboring bacterial community across different P supply levels.They enhance the network complexity of phoD-harboring bacteria,thereby improving the network stability of these bacterial communities and ultimately influencing the availability of soil P.
作者
赵晓坤
方梓西
刘顺莉
潘玮涵
尹江琴
谢小雨
陈远学
陈新平
郎明
ZHAO Xiaokun;FANG Zixi;LIU Shunli;PAN Weihan;YIN Jiangqin;XIE Xiaoyu;CHEN Yuanxue;CHEN Xinping;LANG Ming(Key Laboratory of Low-carbon Green Agriculture in Southwestern China,College of Resources and Environment,Southwest University,Chongqing,China;Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin,Southwest University,Chongqing,China;Academy of Agricultural Sciences,Southwest University,Chongqing,China;College of Resources,Sichuan Agricultural University,Chengdu,Sichuan,China)
出处
《微生物学报》
北大核心
2025年第12期5482-5499,共18页
Acta Microbiologica Sinica
基金
国家自然科学基金(32272800)
国家重点研发计划(2023YFD1900600)
重庆市自然科学基金(CSTB2023NSCQ-MSX0507)
国家玉米产业体系(CARS-02)。
关键词
有机培肥
含phoD基因细菌
优势物种
群落结构
网络稳定性
organic amendments
phoD-harboring bacteria
dominant species
community structure
network stability
