具有N2O还原功能的根际促生菌（PGPR）对于作物生长发育和减排农田土壤温室气体N2O具有重要的作用。申请者前期研究发现，接种N2O还原细菌不仅可以减少土壤温室气体N2O的排放，还可以促进作物的生长。针对目前PGPR减排农田土壤N2O根际生物学机制不清的现状，本项目拟研究自主分离的菌株NRCB10对番茄生长和减排农田土壤N2O的影响，设计和筛选NRCB10特异性引物，通过温室盆栽和田间小区试验研究根际与非根际土壤中NRCB10的存活特征及其对N2O产生与还原细菌群落组成和丰度的影响，进一步通过室内模拟试验研究根系分泌物组分对NRCB10的N2O还原酶活性和转录的调控，揭示NRCB10减排农田土壤N2O的根际生物学机制，探索根系分泌物组分对NRCB10减排农田土壤N2O的调控作用。本项目将为开拓农田土壤N2O减排新途径、研发环境友好的生物肥料提供重要的理论指导。

Plant growth promoting rhizobacteria (PGPR), which are able to reduce nitrous oxide (N2O) to dinitrogen, play vital roles in the growth and development of plants, and the mitigation of N2O from agricultural soils as well. It has been demonstrated in the applicant’s previous study that the inoculation with N2O-reducing denitrifiers to upland soils could mitigate N2O emissions and simultaneously promote the growth of pasture plants in a greenhouse. However, there is limited information on PGPR stains showing both plant growth-promoting and N2O mitigation effects. Moreover, the mechanism of mitigation of N2O by the PGPR remains largely unknown. Recently, the applicant has isolated a novel PGPR strain (named as NRCB10) with N2O mitigation effect, which will be used as the research object and tomato will be used as the research experimental crop. First, the effect of NRCB10 on the growth of tomato and N2O mitigation will be investigated in an upland soil. Second, specific primers for NRCB10 strain will be designed and developed. Third, the survival characteristics of NRCB10, the community composition and abundance of N2O generating and reducing bacteria in both rhizosphere soil and non-rhizosphere soil will be investigated through greenhouse and field plot experiments. The regulation of N2O reductase and transcription in NRCB10 by the root exudate components will be further investigated through laboratory simulated experiments. The final goals of this study are to (1) reveal the rhizospheric biological mechanism of N2O mitigation by the NRCB10 in the upland soil, and (2) explore the mechanism of NRCB10 induced N2O mitigation regulated by root exudate components. This study will provide critical theoretical guidance for opening up a novel way of N2O mitigation in agricultural soil and developing environmental friendly bio-fertilizers.