Effect of Bacillus spp. and Brevibacillus sp. on the Photosynthesis and Redox Status of Solanum lycopersicum

Abstract

Plant-growth-promoting bacteria (PGPB) are gaining attention as a sustainable alternative to current agrochemicals. This study evaluated the impact of three Bacillus spp. (5PB1, 1PB1, FV46) and one Brevibacillus sp. (C9F) on the important crop tomato (Solanum lycopersicum) using the model cv. ‘MicroTom’. The effects of these isolates were assessed on (a) seedlings’ growth and vigor, and (b) adult potted plants. In potted plants, several photosynthetic parameters (chlorophylls (a and b), carotenoids and anthocyanins contents, transpiration rate, stomatal conductance, net CO2 photosynthetic rate, and intercellular CO2 concentration, and on chlorophyll fluorescence yields of light- and dark-adapted leaves)), as well as soluble sugars and starch contents, were quantified. Additionally, the effects on redox status were evaluated. While the growth of seedlings was, overall, not influenced by the strains, some effects were observed on adult plants. The Bacillus safensis FV46 stimulated the content of pigments, compared to C9F. Bacillus zhangzhouensis 5PB1 increased starch levels and was positively correlated with some parameters of the photophosphorylation and the gas exchange phases. Interestingly, Bacillus megaterium 1PB1 decreased superoxide (O2−) content, and B. safensis FV46 promoted non-enzymatic antioxidant defenses, increasing total phenol content levels. These results, conducted on a model cultivar, support the theory that these isolates differently act on tomato plant physiology, and that their activity depends on the age of the plant, and may differently influence photosynthesis. It would now be interesting to analyze the influence of these bacteria using commercial cultivars.

Impact of Plant Growth-Promoting Rhizobacteria Inoculation on the Physiological Response and Productivity Traits of Field-Grown Tomatoes in Hungary

“…Similar results were reported previously as a result of mycorrhiza inoculation, where chlorophyll fluorescence (Fv/Fm) increased in tomato until flowering and fruit setting but decreased with advancing maturity stages, especially under dry growing conditions [45,46]. Some PGPR strains (Bacillus safensis (FV46), and Brevibacillus lateosporus (C9F)) reduced the Fv/Fm value compared to control according to the finding of another study [47], which is similar to our experiment in 2018 (ST2 and ST3) and in 2020 (ST2).…”

Satureja montana Essential Oil, Zein Nanoparticles and Their Combination as a Biocontrol Strategy to Reduce Bacterial Spot Disease on Tomato Plants

“…The superoxide radical was semi-quantified following Gajewska et al [45], with the modifications described by Costa-Santos et al [46]. Briefly, 50 mg of leaf tissue was homogenized in 2 mL of extraction buffer, consisting of phosphate buffer 0.01 M (pH = 7.8), 0.05% (w/v) of nitroblue tetrazolium (NBT) dissolved in 100 µL of DMSO (dimethyl sulfoxide) and 10 mM sodium azide.…”

Glomus sp. and Bacillus sp. strains mitigate the adverse effects of drought on maize (Zea mays L.)

“…Furthermore, the Fv/Fm ratio of Solanum lycopersicum was reduced when three Bacillus spp. were applied ( Costa-Santos et al, 2021 ). Furthermore, Bacillus amyloliquefaciens mixed with Azospirillum brasilense NO40 increased the photosynthetic rate of Triticum aestivum ( Kasim et al, 2013 ).…”