Nitric oxide synthase expression in Pseudomonas koreensis MME3 improves plant growth promotion traits

In this study, the plant growth-promoting rhizobacteria Pseudomonas koreensis MME3 was genetically modified to express a nitric oxide synthase of Synechococcus SyNOS, an atypical enzyme with a globin domain that converts nitric oxide to nitrate. A cassette for constitutive expression of synos was introduced as a single insertion into the genome of P. koreensis MME3 using a miniTn7 system. The resulting recombinant strain MME3:SyNOS showed improved growth, motility, and biofilm formation. The impact of MME3:SyNOS inoculation on Brachypodium distachyon growth and N uptake and use efficiencies under different N availability situations was analyzed, in comparison to the control strain MME3:c. After 35 days of inoculation, plants treated with MME3:SyNOS had a higher root dry weight, both under semi-hydroponic and greenhouse conditions. At harvest, both MME3:SyNOS and MME3:c increased N uptake and use efficiency of plants grown under low N soil. Our results indicate that synos expression is a valid strategy to boost the phytostimulatory capacity of plant-associated bacteria and improve the adaptability of plants to N deficiency. KEY POINTS: • synos expression improves P. koreensis MME3 traits important for rhizospheric colonization • B. distachyon inoculated with MME3:SyNOS shows improved root growth • MME3 inoculation improves plant N uptake and use efficiencies in N-deficient soil.PMID:38358431 | DOI:10.1007/s00253-024-13029-1
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Source Type: research