Native strain Enterobacter 64S1 enhances drought tolerance and melatonin levels of tomato plants

JOFRÉ, MARÍA FLORENCIA; MAMMANA, SABRINA; PÉREZ-RODRIGUEZ, MARÍA MICAELA; GOMEZ, FEDERICO JOSÉ VICENTE; SILVA, MARÍA FERNANDA; COHEN, ANA CARMEN

Rosario

Conferencia; RAFV Conference 2023. XXXIV Argentinian Meeting of Plant Physiology; 2023

Sociedad Argentina de Fisiología Vegetal

In arid and semiarid regions, drought negatively impacts agriculture with severe losses in crop yields. Plant Growth Promoting Rhizobacteria (PGPR) are a sustainable alternative to improve crop production decreasing the fertilizer use. Furthermore, the use of PGPR in plants grown under stress conditions such as drought, salinity, or high temperature, mitigates the effects of stress. Enterobacter 64S1 is a native PGPR isolated from tomato crops of Mendoza. Recently, it has been reported that this strain is able to produce the hormone melatonin (MT) and increases the content of endogenous MT in plants of Arabidopsis thaliana under drought stress. Melatonin protects plants against biotic and abiotic stress, e.g., acting as a scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Therefore, the aim was to determine the effect of inoculation with the Enterobacter 64S1 strain on tomato plants under drought stress conditions and irrigation at field capacity. The plants were grown in a greenhouse for 4 weeks. The treatments were: 1) control and 2) 64S1 strain. After ten days of the inoculation treatment, water stress was applied on half of the plants in each treatment (n=15), while the rest was irrigated to field capacity (well-watered plants, WW). The soil moisture in stressed plants was kept at 30% of field capacity for 15 days by adding lost water. Then, at the end of the treatments, morphological, physiological, and biochemical variables were determined. In addition, plant endogenous MT production was measured in tomato leaves. The inoculated plants under drought stress presented a greater leaf area, stem heigh and dry weight, total chlorophyll content, and Fv/Fm levels. In addition, Enterobacter 64S1 increases the endogenous MT content in tomato plants under drought. This native strain improved the tolerance of tomato plants to drought by improving plant growth, total chlorophyll levels and the maximum efficiency of photosystem II.