耐盐芽孢杆菌ZP-3821的分离与促生功能鉴定OA

[Objective]To screen salt-alkali tolerant plant growth-promoting rhizobacteria(PGPR)with growth-promoting capabilities,so as to provide a theoretical basis and bacterial resources for the improvement of saline-alkali soils and the development of microbial fertilizers.[Method]Rhizosphere soil samples of peanut plants were collected from Hami,Xinjiang Uygur Autonomous Region,and bac-teria were isolated and screened using Luria-Bertani(LB)medium.Based on morphological characte-ristics,physiological and biochemical properties,and 16S rRNA gene sequence analysis,the target strain was identified.The growth capacity of the target strain was evaluated under varying NaCl concen-trations(0-200 g·L⁻¹),temperatures(5-55℃),and pH levels(4-13)to determine its salt tolerance range,temperature tolerance,and pH tolerance.The multiple functional identification media were used to assess the plant growth-promoting functions,including amylase production,siderophore syn-thesis,and cellulase production.Additionally,the capacity for amylase production and biofilm forma-tion was quantitatively determined.Through plate and pot experiments,the growth-promoting effects on tomato and maize seedlings were evaluated,respectively.[Result]A bacterial strain was isolated and identified as Bacillus halotolerans,designated as Bacillus halotolerans ZP-3821.Strain ZP-3821 was capable of growing within a NaCl concentration range of 0-40 g·L-1,a temperature range of 20-50℃,and a pH range of 5-10.The strain exhibited the abilities of fixing nitrogen,producing amy-lase,synthesizing siderophores,secreting cellulase,and forming biofilm.The plate experiment results showed that strain ZP-3821 significantly enhanced the aboveground fresh weight,underground fresh weight,and lateral roots number of tomato seedlings under saline-alkali stress.Under the condi-tion of pH value 8.0+2.0 mmol·L-1 NaHCO₃+0 mmol·L-1 NaCl,compared with the control group,inoculation with ZP-3821 increased the aboveground fresh weight,underground fresh weight,and la-teral roots number by 169.04%,198.37%,and 509.48%,respectively.Pot experiment results indi-cated that under salt stress with a NaCl concentration of 6 g·kg-1,compared to the control,inoculation with strain ZP-3821 increased the underground fresh weight and total fresh weight of maize seedlings by 39.82%and 18.65%,respectively.[Conclusion]Bacillus halotolerans ZP-3821 exhibits excellent salt-alkali tolerance and can promote plant growth under salt-stressed conditions.