Melatonin production by rhizobacteria native strains: Towards sustainable plant growth promotion strategies

JOFRE, MARÍA FLORENCIA; MAMMANA, SABRINA B.; LOPEZ APPIOLAZA, MARTÍN; SILVA, MARÍA FERNANDA; GOMEZ, FEDERICO JOSÉ VICENTE; COHEN, ANA CARMEN

PHYSIOLOGIA PLANTARUM

WILEY-BLACKWELL PUBLISHING, INC

Año: 2023

0031-9317

In the current context of climate change and water deficit, the selection of native beneficial microorganisms, such as plant growth-promoting rhizobacteria (PGPR), has become a trend for sustainable agriculture due to their ability to improve plant-bacteria interaction and minimize the adverse effects on the soil microbiota, commercial PGPR. Until now, the production of phytohormones like melatonin (MT) by native PGPR and their effect on endogenous MT levels in plants have been poorly studied. MT is a ubiquitous phytohormone that protects plants against biotic and abiotic stress by improving the tolerance of stressed plants. In this work, the production of MT by two native PGPR, Enterobacter 64S1 and Pseudomonas 42P4 was evaluated, and then, both PGPR were applied in Arabidopsis thaliana plants grown under drought conditions to assess the inoculation effects. Then, parameters such as plant growth, leaf cellular membrane damage, leaf protective compounds, and endogenous MT levels under drought and irrigation conditions were evaluated. The results demonstrated that native strains Pseudomonas 42P4 and Enterobacter 64S1 produce MT and increase the content of endogenous MT in A. thaliana plants under drought. These native strains improved the tolerance of Arabidopsis plants under drought by preventing oxidative and membrane damage and improving plant growth. To the best of our knowledge, this is the first report on MT production by native PGPR and their effects on endogenous MT levels in Arabidopsis plants, setting the bases to elucidate the role of native PGPR on water deficit conditions.