Synergistic Effect of Plant-Growth-Promoting Rhizobacteria Improves Strawberry Growth and Flowering with Soil Salinization and Increased Atmospheric CO2 Levels and Temperature Conditions

Abstract

Biofertilization with plant-growth-promoting rhizobacteria (PGPR) can positively affect the growth and health of host plants and reinforce their tolerance of stressors. Here, we investigate the use of isolated PGPR consortia from halophytes to improve strawberry growth and flowering performance under saline and elevated CO2 and temperature conditions. Growth, flower bud production, and the photosynthetic apparatus response were determined in strawberry plants grown at 0 and 85 mmol L−1 NaCl and in two atmospheric CO2-temperature combinations (400/700 ppm and 25/+4 °C, respectively). Biofertilization improved strawberry plant growth and flower bud production, independently of salinity conditions, at ambient CO2 and 25 °C, while bacterial inoculation only had a positive effect on plant growth in the presence of salt in high CO2 and at +4 °C. Biofertilizers 1 and 3 generated the largest biomass of strawberries at 400 ppm CO2 and 0 and 85 mmol L−1 NaCl, respectively, while biofertilizer 1 did so in the presence of salt and in an atmosphere enriched with CO2 and at +4 °C. The effect of the consortia was mediated by bacterial strain PGP properties, rather than by an improvement in the photosynthetic rate of the plants. Furthermore, biofertilizers 1 and 2 increased the number of flower buds in the absence of salt, while biofertilizers 3 and 4 did so for salt-inoculated plants at 400 ppm CO2 and at 25 °C. There was no effect of inoculation on flower bud production of plants grown at high CO2 and at +4 °C. Finally, we concluded that the effect of bacterial inoculation on strawberry growth and flowering depended on the type of bacterial strain and growth conditions. This highlights the importance of developing studies considering stress interaction to assess the real potential of biofertilizers.

Beneath the blooms: Unearthing the effect of rhizospheric bacteria on floral signals and pollinator preferences

“…These microbial associations have been shown to increase plant size and biomass, thereby influencing pollinator behaviour and ultimately impacting plant yield (Backer et al, 2018). In line with these findings, numerous studies have consistently demonstrated that inoculating soil with PGPR leads to increased flower production in various ornamental and crop plants (Göre & Altin, 2006;Kumar et al, 2016;Kumari et al, 2016;Lyu et al, 2022;Nordstedt et al, 2020;Redondo-Gómez et al, 2022). Our results support this trend, as the inoculation of B. amyloliquefaciens on both cultivated and wild tomato species resulted in increased flower production and biomass.…”

Multitrait Pseudomonas sp. isolated from the rhizosphere of Bergenia ciliata acts as a growth-promoting bioinoculant for plants

“…Early flowering might be due to the indirect effect of PGPR, which can increase the availability of nutrients in the soil and enhance different physiological processes. Redondo-Gómez et al (2022) reported flower bud induction in strawberry plants after inoculation with PGPRs and colonization by Paenibacillus lentimorbus also resulted in more flowers and seeds in tobacco, as reported by Kumar et al (2016). It may be hypothesized that early flowering in healthy plants of A. paniculata may reduce its life cycle.…”

Improving Grapevine Heat Stress Resilience with Marine Plant Growth-Promoting Rhizobacteria Consortia

“…In summary, Vitis vinifera, when inoculated with the PGPR consortia, had a significant amelioration effect on heatwave-induced stress. These consortia were designed with tested and proven plant growth-promoting rhizobacteria that presented great bioinoculant potential during in vitro assays [27,28] and were built with no differentiating factor among them; however, superior oxidative protection and overall fitness were seen in consortium 2. Consortia effectiveness variation can have many explanations, including biotic and abiotic stress sensitivity [92], soil biochemistry [93] and leaf surface biochemistry [94].…”

“…Salt marshes are unique ecosystems that are exposed to high salinity and fluctuations in water levels, making them a potential source of PGPR with stress tolerance properties [24]. The bioaugmentation of plants with these marine PGPR has been shown to aid the plants in resisting and overcoming several abiotic challenges from nutrient deprivation [25] and osmotic stress [26,27], including thermal and extreme stress [28,29]. Moreover, a single strain microorganism usage does not allow the activation of all possible growth-promoting mechanisms; thus, in order to elicit all potential traits, the application of PGPR consortia is increasingly more common in agricultural practices and is of current interest in research [28,30].…”