Plant growth-promoting properties and anti-fungal activity of endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta in arid lands

Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.

Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.

Identification of Growth-promoting Bacteria from Rhizosphere of Pastures and Their Effects on Growth of Lotus corniculatus L.

[Objectives] This study was conducted to explore the interaction between nitrogen-fixing and phosphate-solubilizing strains and the optimal combination of different functional strains,in order to provide a theoretical basis for the development of PGPR compound fertilizers suitable for local environment.[Methods] In this study,16S rDNA gene sequence analysis was used to identify fast-growing and competitive strains from pasture nodules and rhizosphere soils in Guizhou Province,and three representative Rhizobia and phosphorus-solubilizing bacteria were chosen for the test of bacterial combination when reducing 50% of nitrogen and 30% of phosphorus.The effects of different strain combinations on the plant height,root length,aboveground and underground biomass of Lotus corniculatus L.were investigated,and the total nitrogen and total phosphorus contents of the plants were determined.[Results] The mixed bacterial agents could promote the increase of root biomass,and the effects of A1,A3,B3 and C3 were the most obvious.The fresh weight and dry weight of the roots of L.corniculatus increased by 30.35%-168.45% and 26.43%-180.00%,respectively,and A3,B3,B2 and C3 had the best effects.The total phosphorus content of the plants increased by 12.79%-55.25% compared with the CK2;and most of the bacterial agents with significant growth-promoting effects showed decreased total nitrogen contents,while those with non-significant growth-promoting effects showed significantly-increased total nitrogen contents,which were not as much as the CK1.Comprehensively,the most productive combination was C3,namely R27-2 Rhinohizobium fredii and P33-3 Stenotrophomonas rhizophila.[Conclusions] This study can provide a theoretical basis for the production and promotion of bacterial fertilizers.

Effect of Plant Growth-Promoting Rhizobacteria at Various Nitrogen Rates on Corn Growth

Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.

Potential seed germination-enhancing plant growth-promoting rhizobacteria for restoration of Pinus chiapensis ecosystems

Rhizosphere soil samples of three Pinus chiapensis sites were analyzed for their physicochemical properties,soil bacteria isolated and screened in vitro for growthpromoting abilities.Nine isolates that showed promise were identified to five genera Dyella,Luteimonas,Euterobacter,Paraburkholderia and Bacillus based on the sequences of16 S rRNA gene.All the strains were isolated from nondisturbed stands.These bacteria significantly decreased germination time and increased sprout sizes.Indole acetic acid and gibberellin production and phosphate solubilisation were detected.Results indicate that these biochemicals could be essential for P.chiapensis distribution and suggest the possibility that PGPR inoculation on P.chiapensis seeds prior to planting could improve germination and possibly seedling development.

Application Progress of Plant Growth-promoting Bacteria in Crops

Plant growth-promoting bacteria(PGPBs)can promote plant growth and improve crop yield.They can induce plant systemic resistance to resist biotic and abiotic stresses.In recent years,with the development of green ecological agriculture,new biological fertilizers such as microbial inocula and microbial fertilizers based on PGPBs have been gradually applied in crop planting.Based on plant growth promotion and disease control,the application progress of PGPBs in crops from the aspects of growth promotion mechanism,growth promotion effect,resistance to biological and abiotic stresses were discussed,aiming to provide reference for the relevant research and application of PGPBs in crops.

Synergistic combination of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria modulates morpho-physiological characteristics and soil structure in Nitraria tangutorum bobr.Under saline soil conditions

Nitraria tangutorum Bobr.,a typical xero-halophyte,can be used for vegetation restoration and reconstruction in arid and semiarid regions affected by salinity.However,global climate change and unreasonable human activity have exacerbated salinization in arid and semi-arid regions,which in turn has led to the growth inhibition of halophytes,including N.tangutorum.Arbuscular mycorrhizal fungi(AMF)and plant growth-promoting rhizobacteria(PGPR)have the potential to improve the salt tolerance of plants and their adaptation to saline soil environments.In this study,the effects of single and combined inoculations of AMF(Glomus mosseae)and PGPR(Bacillus amyloliquefaciens FZB42)on N.tangutorum were evaluated in severe saline soil conditions.The results indicate that AMF and PGPR alone may not adapt well to the real soil environment,and cannot ensure the effect of either growth promotion or salt-tolerance induction on N.tangutorum seedlings.However,the combination of AMF and PGPR significantly promoted mycorrhizal colonization,increased biomass accumulation,improved morphological development,enhanced photosynthetic performance,stomatal adjustment ability,and the exchange of water and gas.Co-inoculation also significantly counteracted the adverse effect of salinity on the soil structure of N.tangutorum seedlings.It is concluded that the effectiveness of microbial inoculation on the salt tolerance of N.tangutorum seedlings depends on the functional compatibility between plants and microorganisms as well as the specific combinations of AMF and PGPR.

植物根际促生菌在烟草根茎类病害防治中的应用研究进展

烟草是重要的经济作物,经济价值高。烟草根茎类病害的发生导致一定的烟草损失。本文阐述了烟草根黑腐病、烟草黑胫病和烟草青枯病等烟草根茎类病害的发生和危害,分析了烟草根茎类病害的防治现状,包括农业防治、化学防治和生物防治等内容,提出了植物根际促生菌的研究进展,探讨了其作用机制及在防治烟草病害中的应用前景,总结了用于防治烟草病害的植物根际促生菌主要种类,提出了相关展望,以期为有效防治烟草根茎类病害和推广应用植物根际促生菌提供参考。

Selection and validation of reference genes for quantitative real-time polymerase chain reaction analyses of Serratia ureilytica DW2

Background:Serratia ureilytica DW2 is a highly efficient phosphate-solubilizing bacteria isolated from Codonopsis pilosula rhizosphere soil that can promote the growth of C.pilosula;nonetheless,until now,no validated reference genes from the genus Serratia have been reported that can be used for the normalization of quantitative real-time polymerase chain reaction(RT–qPCR)data.Methods:To screen stable reference genes of S.ureilytica DW2,the expression of its eight candidate reference genes(16S rRNA,ftsZ,ftsA,mreB,recA,slyD,thiC,and zipA)under different treatment conditions(pH,temperature,culture time,and salt content)was assayed by RT–qPCR.The expression stability of these genes was analyzed using different algorithms(geNorm,NormFinder,and BestKeeper).To verify the reliability of the data,the expression of the glucose dehydrogenase(gdh)gene under different soluble phosphate levels was quantified using the most stably expressed reference gene.Results:The results showed that the zipA and 16S rRNA genes were the most stable reference genes,and the least stable genes were thiC and recA.The expression of gdh was consistent with the phosphate solubilization ability on plates containing the National Botanical Research Institute phosphate growth medium.Conclusion:Therefore,this study provides a stable and reliable reference gene of Serratia for the accurate quantification of functional gene expression in future studies.

Rice(Oryza sativa L.)plant protection using dual biological control and plant growth-promoting agents:Current scenarios and future prospects

Various microorganisms live in association with different parts of plants and can be harmful,neutral,or beneficial to plant health.Some microbial inhabitants of plants can control plant diseases by contesting with,predating on,or antagonizing plant pathogens and by inducing systems for plant defense.A range of methods,including plant growth-promoting microorganisms(PGPMs)as biological control agents(BCAs)(BCA-PGPMs)are used for the biological management and control of plant pathogens.Some BCAs interact with plants by inducing resistance or priming plants without direct interaction with the pathogen.Other BCAs operate via nutrient competition or other mechanisms to modulate the growth conditions for the pathogen.Generally,PGPMs can be applied alone or together with other chemicals or carriers to control various crop diseases.This review highlights the effective types of BCA-PGPMs and their applications,roles,carrier based-formulations,and responses to rice(Oryza sativa L.)pathogens.Future plant disease management prospects are promising,and growers’increasing demand for BCA-PGPM products can be exploited as an effective approach to the management of plant diseases,as well as to improve yield,environmental protection,biological resources,and agricultural system sustainability.

Rhizobacteria facilitate physiological and biochemical drought tolerance of Halimodendron halodendron (Pall.) Voss

Growth-promoting bacteria(GPB)have shown promising effects on serving plants against environmental constraints such as drought.Nevertheless,simultaneous effects of different GPB have less been considered for arid land plants and under field conditions.We investigated the effects of single and combined application of GPB,including free-living nitrogen-fixing bacteria(NFB),phosphate solubilizing bacteria(PSB),potassium solubilizing bacteria(KSB),a combination of NFB,PSB,and KSB(NPK),and control,at three drought stress treatments.In order to better understand the interactions between drought and GPB,we measured the morphological,biochemical,and physiological plant traits.The target plant was salt tree(Halimodendron Halodendron(Pall.)Voss),a legume shrub native to arid lands of Central and West Asia.All biofertilizer treatments enhanced the growth,physiology,and biochemistry of salt tree seedlings,and there were significant differences among the treatments.KSB and PSB treatments increased photosynthetic pigments,but KSB treatment was more efficient in transpiration rate and stomatal regulation and increased the soluble carbohydrates.PSB treatment had the highest effect on root traits,such as taproot length,root volume,cumulative root length,and the ratio of root to shoot.NFB treatment enhanced root diameter and induced biomass translocation between root systems.However,only the application of mixed biofertilizer(i.e.,NPK treatment)was the most significant treatment to improve all plant morphological and physiological characteristics of salt tree under drought stress.Therefore,our results provided improvement of some specific plant traits simultaneous with application of three biofertilizers to increase growth and establishment of salt tree seedlings in the degraded arid lands.

不同复合菌剂对甘薯产量和品质的影响

植物促生菌对植物的生长发育和品质形成具有一定的影响。本文以甘薯品种朝日8号为试验材料,研究不同复合菌剂对甘薯产量和品质的影响。结果表明:不同复合菌剂对甘薯产量均有一定影响,其中以组合1[含苏云金芽孢杆菌(Bt1)、肠杆菌属(Es)、戊糖片球菌(Pp1)]对甘薯的增产效果最好,与对照相比,增产率达到17.03%;复合菌剂处理后,薯块大部分营养品质指标得到了提升,DPPH自由基清除率变幅为64%~95%,说明复合菌剂对甘薯品质也产生了一定影响。

Efficacy of Bacillus subtilis MBI 600 Against Sheath Blight Caused by Rhizoctonia solani and on Growth and Yield of Rice

Rice sheath blight disease （ShB）, caused by Rhizoctonia solani, gives rise to significant grain yield losses. The present study evaluated the efficacy of Integral, the commercial liquid formulation of Bacillus subtilis strain MBI 600, against rice ShB and for plant growth promotion. In greenhouse studies, four log concentrations of Integral （from 2.2×10^6 to 2.2×10^9 cfu/mL） were used as seed treatment （ST）. After 25 d, seedlings were dipped （SD） into Integral prior to transplanting. At 30 d after transplanting （DAT）, leaf sheaths were inoculated with immature sclerotia of the pathogen. At 45 DAT, a foliar spray （FS） with Integral was applied to some treatments. The fungicide control was 50% carbendazim at 1.0 g/L, and a nontreated control was also included. Overall, there were 10 treatments, each with five replications. ShB severity was rated at 52 DAT, and seedling height and number of tillers per plant were rated at 60 DAT. In 2009, two field trials evaluated Integral at 2.2×10^8 and 2.2×10^9 cfu/mL. Integral was applied as ST, and seedlings were produced in a nursery bed. After 32 d, seedlings were treated with Integral as SD and transplanted into 10 m^2 blocks. Foliar sprays were given at 45 and 60 DAT. There were seven treatments, each with eight replications arranged as a factorial randomized complete block design. At 20 DAT, the plots were broadcast inoculated with R. solani produced on rice grains. Seedling height before transplanting, ShB severity at 90 DAT, and grain yield at harvest were recorded. Integral at 2.2×10^9 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions. The Integral treatments of ST ＋ SD ＋ FS at 2.2×10^9 cfu/mL significantly suppressed ShB over other treatments. In field studies, Integral provided significant increase of seedling height in nursery, and number of tillers per plant, compared with the control. ShB severity was significantly suppressed with higher concentrations of Integral compared to lower concentrations. Grain yield were the highest at an Integral concentration of 2.2×10^9 cfu/mL. Overall, Integral significantly reduced ShB severity, enhanced seedling growth, number of tillers per plant and grain yield as ST ＋ SD ＋ FS at the concentration of 2.2×10^9 cfu/mL under the conditions evaluated.

番茄内生细菌的分离及其促生活性研究(英文)

[Objective] The study aimed to investigate the growth-promoting activities of endophytic bacteria from tomato plants.[Method]The endophytic bacteria isolated from different tissues of tomato plants were analyzed for the effects of their growth-promoting activities on the germination and growth of tomato plants.The bacteria with growth-promoting activity were preliminarily identified.[Result]Totally 59 endophytic bacterial strains were isolated from roots and stems of tomatoes,of which 4 showed significantly growth-promoting activity to germination and growth of tomato.The results suggest that these strains are endowed with the potential capability of growth-promoting.[Conclusion]The endophytic bacteria with growth-promoting activity were found among the isolates from tomato plants.This provided a good foundation for utilization of these bacteria with growth-promoting activity.

香蕉根际促生菌的抑菌活性及对作物生长的促进作用

【目的】研究4种香蕉根际促生菌对香蕉枯萎病镰刀菌和几种重要作物病原菌的抑菌活性,及其对番茄和玉米的促生作用.【方法】在培养皿中测定根际促生菌对作物病原菌的拮抗作用,通过盆栽试验测定根际促生菌发酵液对作物生长的促进作用.【结果和结论】从健康香蕉根际土中分离获得的枯草芽孢杆菌Bacillus.subtilis、解淀粉芽孢杆菌B.amyloliquefaciens、耳炎假单胞菌Pseudomonas.otitidis和绿针假单胞菌Ps.choloeaphtis对香蕉枯萎病镰刀菌4号小种Fusarium oxysporum f.sp.cubense具有强烈的抑菌活性,对番茄早疫病菌Alternaria solani、玉米纹枯病菌Rhizoctonia solani、荔枝炭疽病菌Colletotrichum gloeosporioides Penz.、香蕉炭疽病菌C.musarum Cooke et Mass、青瓜枯萎病菌F.oxysporum(Schl.)f.sp cucumerinum Owen、小麦赤霉病菌F.graminearum和荔枝霜霉病菌Penorophythora litchi Chen等作物病原菌也具有很好的抑菌活性;4种香蕉根际土壤细菌中耳炎假单胞菌生长最快、抑菌效果最好,其生长半径分别是枯草芽孢杆菌、解淀粉芽孢杆菌、绿针假单胞菌的2.75、2.61和2.70倍,其对香蕉枯萎病、番茄早疫病菌、玉米纹枯病菌、荔枝炭疽病菌、香蕉炭疽病菌、青瓜枯萎病菌、小麦赤霉病菌和荔枝霜霉病的抑菌率分别达到50.70%、62.95%、70.85%、68.10%、58.58%、59.30%、51.34%和63.08%;用耳炎假单胞菌发酵液培养植物使番茄和玉米株高分别提高16%和33%,并且使番茄叶片总叶绿素含量增加40%.以上结果表明,香蕉根际微生物耳炎假单胞菌对作物病原菌有很好的抑菌活性,并且促进番茄和玉米的生长.

烟草内生细菌Itb57和Itb295菌株的促生与抑菌作用测定(英文)

[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promoting effects of bacterial suspension ~ff endophytic bacteria Itb57 and Itb295 on tobacco seedling un- der different treatment modes were studied using potting method in greenhouse. The antagonistic action of bacterial suspension of endophytic bacteria Itb57 and Itb295 on Phytophthora nicotianae, Alternaria alternata and Botrytis cinerea were measured by duel culture method. [ Result] Bacterial suspensions of enduphytic bacteria Itb57 and Itb295 had certain growth-promoting effects on tobacco seedling, which could significantly increase the fresh weight and dry weight in aerial part; the growth-promoting effect of soaking ＋ spraying and irrigating treatment was the best. Itb57 strain had good antagonistic action against P. nicotianae. A. alterna- ta and B. cinerea, while Itb295 strain only had good antifungal effect against P. nicotianae. [ Conclusion] The results provided basis for the study and application of tobacco endophytic bacteria strains Itb57 and Itb295 in biocontrol of tobacco diseases.

植物根围促生细菌菌剂增强玉米干旱耐受性研究

选用植物根围促生细菌(PGPR)菌剂BBS处理玉米幼苗,研究干旱胁迫下玉米幼苗叶片相关生理特性及基因表达差异。结果表明,干旱胁迫15 d后,BBS处理组玉米幼苗的萎蔫程度显著低于对照组;处理组植株叶片MDA含量仅为对照组的74.35%,叶片脯氨酸和可溶性糖含量分别是对照组的3.39倍和1.07倍;处理组植株叶片ZmP5CS1的表达水平及SOD活性均显著高于对照组;BBS处理组植株叶片在干旱胁迫过程中一直保持较低的H_2O_2含量。研究得出,BBS处理能够有效减缓干旱胁迫对玉米幼苗造成的伤害,进而加速正常浇水后的恢复。处理组植株叶片NCED1和ZmDREB2.7的高水平表达也表明干旱胁迫下玉米幼苗与BBS的互作过程可能有依赖ABA信号途径及不依赖ABA信号途径的共同参与。

1株降解PCBs细菌的鉴定及其bphA1序列分析

通过富集培养方法从受多氯联苯(polychlorinated biphenyls,PCBs)污染的苜蓿根际土壤富集分离到1株PCBs降解细菌并命名为A1。根据形态特征和16S rDNA序列分析,鉴定该菌株为纽伦堡潘多拉菌Pandoraeanorimbergensis。采用休眠细胞体系测定该菌株对Aroclor1242的降解能力,经GC-MS色谱分析,该菌株在72 h内对Aroclor1242的总降解率为56.7%。通过对其bphA1基因的克隆和序列分析,结果表明:P.norimbergensis的bphA1基因与Pandoraea sp.JB1的bphA1基因序列同源性为100%;核酸序列转化成氨基酸序列后,该菌的bphA1蛋白结构预测模型与Comamonas testosteroni B-356具有99.37%的相似性。

植物根际促生细菌在烤烟提质增产中的作用

为分析植物根际促生细菌(Plant growth-promoting rhizobacteria,PGPR)在烤烟提质增产中的作用,从攀枝花烟区优质烟株根际土壤中分离筛选出促生性好且相互之间不存在拮抗作用的产吲哚乙酸菌、溶磷菌和解钾菌,这3种细菌的混合物即为多功能PGPR混合菌剂。采用盆栽试验和大田试验,研究了多功能PGPR混合菌剂对烤烟提质增产的作用。结果表明:多功能PGPR混合菌剂可改善烤烟的农艺性状及烟叶的化学品质,降低烤烟发病率。以复合肥为底肥施加PGPR混合菌剂可使中上等烟叶比例提高22.0%;以复合肥和有机肥为底肥,施加PGPR混合菌剂可使中上等烟叶比例和产值分别提高34.5%和26.4%。

具有ACC脱氨酶活性的红枣根际促生菌株的分离筛选及其促生效果研究

采用定向富集法从红枣根际土壤分离筛选具有ACC脱氨酶活性的细菌,同时检测其产生长素(IAA)、固氮和解磷等促生特性。结合形态特征和16S rDNA序列分析对菌株进行鉴定,并采用盆栽试验验证3株高效产ACC脱氨酶的根际促生菌株Pseudomonas fluorescens、Pseudomonas putida和Serratia plymuthica对红枣植株生长的影响。结果表明:1)从红枣根际共分离出10株产ACC脱氨酶的菌株,其ACC脱氨酶活性在14.23~433.05μmol/(mg·h)。这些菌株都具有产IAA、固氮和解无机磷能力。2)经鉴定,10株菌株分别属于假单胞菌属(Pseudomonas)、芽孢杆菌属(Bacillus)和沙雷氏菌属(Serratia)。3)接种Pseudomonas putida菌剂和Serratia plymuthica菌剂均可显著促进红枣植株生长发育,提高植株株高、生物量、叶片氮及磷含量。2种菌株的接种效应明显优于Pseudomonas fluorescens菌剂,且复合菌株应用促生效果优于单一菌株。