Compatible Consortium of Endophytic Bacillus halotolerans Strains Cal.l.30 and Cal.f.4 Promotes Plant Growth and Induces Systemic Resistance against Botrytis cinerea

Abstract

Evaluating microbial-based alternatives to conventional fungicides and biofertilizers enables us to gain a deeper understanding of the biocontrol and plant growth-promoting activities. Two genetically distinct Bacillus halotolerans strains (Cal.l.30, Cal.f.4) were evaluated for the levels of their compatibility. They were applied individually or in combination under in vitro and greenhouse conditions, using seed bio-priming and soil drenching as inoculum delivery systems, for their plant growth-promoting effect. Our data indicate that application of Cal.l.30 and Cal.f.4 as single strains and as a mixture significantly enhanced growth parameters of Arabidopsis and tomato plants. We investigated whether seed and an additional soil treatment with these strains could induce the expression of defense-related genes in leaves of young tomato seedling plants. These treatments mediated a long lasting, bacterial-mediated, systemic-induced resistance as evidenced by the high levels of expression of RP3, ACO1 and ERF1 genes in the leaves of young tomato seedlings. Furthermore, we presented data showing that seed and soil treatment with B. halotolerans strains resulted in an effective inhibition of Botrytis cinerea attack and development on tomato leaves. Our findings highlighted the potential of B. halotolerans strains as they combine both direct antifungal activity against plant pathogens and the ability to prime plant innate immunity and enhance plant growth.

Microbial consortium mediated acceleration of the defense response in potato against Alternaria solani through prodigious inflation in phenylpropanoid derivatives and redox homeostasis

“…Similar findings were observed by Kumar et al [ 98 ], who suggested that microbial consortiums of B. subtilis OTPB 1 and T. harzianum OTPB 3 coated tomato seeds showed elevated plant growth and induction of systemic resistance compared to their single-treatment counterparts. Recent studies conducted by Tsalgatidou et al [ 99 ] reported that tomato seed biopriming with a combination of Bacillus halotolerans (Cal.l.30 and Cal.l.4) gave better results in plant growth promotion parameters such as shoot and root length and plant biomass compared to untreated plants under pathogen-challenged conditions. In another investigation, the combined treatment of P. gessardi EU-LWNA-25, Bacillus sp.…”

Isolation and screening rhizobacteria to control <i>Gilbertella persicaria</i> causing dragon fruit rot

“…rough the above evidence, it could be seen that the compatibility varies with each bacterial strain. e compatibility of antagonizing bacterial strains might enhance the ability to biocontrol phytopathogenic fungi, as reported by Palmieri et al (2016) and Tsalgatidou et al (2023). All of the four bacterial strains selected in this study were compatible, so they could form ideal combinations to be applied to control G. persicaria GTC2.3.1.…”

Diverse plant promoting bacterial species differentially improve tomato plant fitness under water stress

“…Bacterial characterization and their impact on tomato growth Among the characterized strains, it is worth noting the presence of Bacillus halotelarans that is a species harboring strains with growth promoting effects, as recently reported by Tsalgatidou et al (2023), and B. butanolivorans, which is known to be able to induce drought tolerance in pepper plants (Kim et al, 2022). A Peribacillus simplex strain was isolated from soil of tomato cultivation and, interestingly, this species has shown the capacity to accumulate lead and to have a biosorption potential (Chamekh et al, 2021).…”