γ-聚谷氨酸对棉花生长与根际微生物的影响

Effects ofγ-polyglutamic acid on cotton growth and rhizosphere microorganisms

[目的]我国是一个农业大国,肥料利用率低下制约农业发展。如何提高肥料利用率成为我国农业发展的重要课题。γ聚谷氨酸(γPGA)因其特殊的分子结构,在提高肥料利用率方面显示了巨大潜力。因此γPGA的应用对实现农业和生态的可持续发展具有重要意义。本文旨在探究棉花植株生长及根际土壤微生物对γPGA的响应。[方法]通过盆栽实验,利用高通量测序技术分析各处理土壤微生物群落。[结果]稀释150倍的γPGA显著促进棉花生长,株高增幅45.49%、茎粗增幅13.14%、主茎叶数增幅51.88%、果枝数增幅300.75%。配施γPGA后,土壤全磷、铵态氮、速效磷、速效钾含量显著提高,且在棉花采摘后依旧维持较高水平。高通量测序结果显示γPGA配施化肥会降低细菌的ACE、Chao1、Simpson、Shannon指数,增加真菌的ACE、Chao1、Simpson、Shannon指数。配施γPGA的采后土壤中变形菌门(Proteobacteria)相对丰度下降13.49%、放线菌门(Actinobacteriota)增加12.37%、芽单胞菌门(Gemmatimonadota)增加30.08%、拟杆菌门(Bacteroidota)下降6.93%、子囊菌门(Ascomycota)下降15.35%、担子菌门(Basidiomycota)增加195.47%、被孢霉门(Mortierellomycota)下降10.49%。与单施化肥和蒸馏水对照相比,γPGA配施化肥后,土壤中各菌门依旧保持高相对丰度。群落功能表型结果显示,配施γPGA土壤微生物偏向需氧型和植物共生型。进一步的RDA分析表明,土壤全氮、全磷和全钾含量是影响微生物优势菌门的关键因子。[结论]γPGA能调节土壤微生物群落变化和促进作物生长,富集有益微生物,在作物采摘后依旧维持较高的土壤生物活性,有利于农业生产。

[Objective]China is a major agricultural country with low fertilizer utilization efficiency,which restricts agricultural development.Improving the fertilizer utilization efficiency has become an important issue for agricultural progress in China.γ-polyglutamic acid(γ-PGA)exhibits great potential in improving fertilizer utilization efficacy due to its unique molecular structure.Therefore,the application ofγ-PGA is of significant importance in achieving sustainable agricultural and ecological development.This study aimed to investigate the response of cotton plant growth and rhizosphere soil microorganisms toγ-PGA.[Methods]Through pot experiments and high-throughput sequencing technology,the microbial communities of each treatment was analyzed.[Results]A 150-fold dilutedγ-PGA significantly stimulated cotton growth,resulting in a 45.49%increase in plant height,a 13.14%increase in stem diameter,a 51.88%increase in main stem leaf count,and a 300.75%increase in fruit branch count.The co-application ofγ-PGA significantly elevated the contents of soil total phosphorus,ammonium nitrogen,available phosphorus,and available potassium,which remained at high levels post-cotton harvest.High-throughput sequencing results indicated thatγ-PGA combined with chemical fertilizer lowered the ACE,Chao 1,Simpson,and Shannon indices of bacteria,while elevating those of fungi.In conjunction withγ-PGA,the relative abundance of Proteobacteria decreased by 13.49%,Actinobacteriota increased by 12.37%,Gemmatimonadota increased by 30.08%,Bacteroidota decreased by 6.93%,Ascomycota decreased by 15.35%,Basidiomycota increased by 195.47%,and Mortierellomycota decreased by 10.49%.Compared to single chemical fertilizer application and distilled water application,the co-application ofγ-PGA and fertilizer maintained high relative abundance of various microbial phyla in the soil.Community functional phenotype analysis showed thatγ-PGA co-application favored aerobic and plant-symbiotic microorganisms.Further RDA analysis showed that soil total nitrogen,total phosphorus,and total potassium contents were key factors influencing the dominance of microbial phyla.[Conclusion]γ-PGA can regulate changes in soil microbial communities,promote crop growth,enrich beneficial microorganisms,and maintain higher soil microbial activity after crop harvest,which is beneficial for agricultural production.