Isolation and Screening of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase producing PGPR from Paeonia lactiflora rhizosphere and enhancement of plant growth

Plant growth-promoting rhizobacteria (PGPR) work in a variety of ways to promote plant growth and increase crop yield. They've recently gotten a lot of attention in crops, but not so much in ornamental plants. In this study, 13 PGPR strains containing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase named YDSY1-13 were isolated from the rhizosphere soil of four Paeonia lactiflora cultivars using the medium with ACC as the sole nitrogen source. The ACC deaminase activity, IAA synthesis ability, phosphorus-solubilizing ability, and siderophile production ability of these strains were significantly different, YDSY11 has the highest ACC deaminase activity and YDSY8 has the highest ability to synthesize IAA. The pot experiment showed that inoculation with YDSY8 and YDSY11 dramatically enhanced the photosynthetic capacity, nutrient accumulation, and antioxidant enzyme activity of Paeonia lactiflora. The Petri-dish growth-promoting experiment revealed that PGPR strains boosted Arabidopsis thaliana development, with different strains having different impacts on root morphology, including main root length, number of root tips and lateral roots, and root hair density. Among them, YDSY1, YDSY2, YDSY4, and YDSY8 have the greatest effect on increasing A. thaliana biomass, and the increase in aboveground biomass was positively correlated with that of underground biomass, with the exception of YDSY8. Different strains have diverse growth-promoting abilities based on their growth-promoting characteristics, and this ability is mostly controlled by the combined effect of different growth-promoting characteristics. In addition, we found that the same PGPR may have different growth-promoting mechanisms for different plants. This study provides primary data for the development and utilization of rhizosphere growth-promoting bacteria of P. lactiflora and lays a foundation for further research on the growth-promoting mechanism of PGPR and provides a solution for alleviating fertilizer pollution to the environment.

Automated summary

Plant growth-promoting rhizobacteria (PGPR) strains were isolated from the rhizosphere soil of Paeonia lactiflora cultivars and found to have diverse growth-promoting abilities and mechanisms. Inoculating with these strains significantly enhanced the growth and development of Paeonia lactiflora and Arabidopsis thaliana.