| Peanut is an important dual-use crop for oil and grain,and the use of functional microorganisms and the construction of synthetic flora is an effective measure to promote the growth of peanut crop,improve peanut quality,and achieve weight loss and efficiency in peanut farming.In this study,for peanut with different tumor capacity,we isolated and screened strains with high efficiency of phosphorus,potassium,nitrogen fixation,indole acetic acid(IAA)and iron carrier production from peanut inter-root soil,combined with high efficiency nitrogen fixing rhizobacteria to build synthetic flora for peanut with different tumor capacity,and laid the foundation for the application of microbial fertilizer and synthetic flora.The main research contents and results are as follows:(1)Screening of peanut with different nodulation ability.The greenhouse pot method was used to select peanut with different nodulation ability from 22 peanut varieties.Three high-efficient nodulation varieties(Huayu 20,Huayu 52,Jihua 8),four low-efficiency nodulation varieties(Jihua 15,Yuhua 91,Shangyan 9807,Shanhua 11)and one non-nodulation variety(SA109)were screened.(2)Isolation of microorganisms in the rhizosphere.A total of 396 strains were isolated from the rhizozoar soil of Pingdu City,Qingdao City,Qixia City,Yantai City,Laishan District and Fushan District of Shandong Province with different nodulation ability.The haplotypes were divided by 100% 16 S r RNA gene consistency,and a total of159 haplotypes were obtained.These strains belong to four phyla: There were 66 genera of Actinomycetota,Bacillota,Bacteroidota and Pseudomonadota.The dominant genera were Streptomyces(46 strains,accounting for 11.62%)and Burkholderia(39 strains,accounting for 11.62%).Pseudomonas(34 strains,8.59%)and Rhizobium(34 strains,8.59%).(3)Isolation of peanut rhizobia and screening of efficient nitrogen-fixing strains.Twenty strains of rhizobia were isolated from the root nodules of peanut plants harvested from Qixia and Fushan districts of Yantai City,and these bacteria were classified into four species of Bradyrhizobium based on the phylogenetic relationship of the recombination protein A(recA)gene.Greenhouse pot experiments showed that Bradyrhizobium ottawaense YTU21486 was an efficient nitrogen fixing strain.(4)High-efficiency functional strain screening.The ability of phosphorus solubilization,potassium solubilization,nitrogen fixation,IAA production and iron carrier production were evaluated for the isolated peanut inter-root microorganisms obtained,and the functional strains were quantitatively re-screened to obtain highly efficient functional strains.The results showed that 124 strains had the ability to detoxify organic phosphorus,among which Brevundimonas sp.YTU21021 had the strongest ability to detoxify organic phosphorus,with the phosphorus solubilization amount of 1.12 mg/L;60 strains had the ability to detoxify inorganic phosphorus,among which Acinetobacter sp.YTU21009 had the strongest ability to detoxify inorganic phosphorus,with the phosphorus solubilization amount of 7.04 mg/L;59 strains had the ability to detoxify potassium,with the phosphorus solubilization amount of 7.04 mg/L.59 strains have potassium solubilizing ability,among which Microbacterium sp.YTU21359 has the strongest potassium solubilizing ability,with soluble potassium content of 10.60 mg/L;10 strains are non-symbiotic nitrogen fixing bacteria,among which strains Kosakonia sp.YTU21262 and Kaistella s sp.YTU21366 have better effect on peanut promotion There are 117 strains with IAA producing ability,among which Enterobacter sp.YTU21054 has the strongest IAA producing ability with 184.19 mg/L;there are 26 strains with iron carrier producing ability,among which Burkholderia sp.YTU21051 has the strongest iron carrier producing ability with As/Ar of 0.90.(5)Construction of synthetic colonies suitable for peanut with different tumorigenic ability.The greenhouse pot experiments showed that the best growth promotion effect was achieved by the synthetic bacterium group B,which effectively increased the chlorophyll content and above-ground dry weight of peanuts with three different tumorigenic abilities,better than the other two groups of bacterium groups and the single inoculation rhizobia group.To sum up,the rhizosphere is rich in microbial diversity and contains multi-functional microorganisms.In this study,the highly functional microorganisms obtained by screening and the synthetic community constructed had significant growth promotion effect on peanut,which laid a theoretical foundation for the development and application of bacterial fertilizer suitable for peanut with different nodulation abilities. |
