Introduction Rhizosphere microbiome is affected and modulated by the complex mixtures of bioactive molecules that are released by plant roots. In this work, two promising plant growth-promoting strains of Streptomyces spp. (DEF17 and DEF19) were evaluated for their capacity to modulate tomato roots and exudates metabolic profile and influence Fusarium oxysporum f. sp. lycopersici (Fol). Methods Dual culture assays, chemotropism assays, and in planta pathogenesis assays were performed to evaluate the capability of the strains to inhibit Fol growth, repel Fol conidia, and induce plant defense mechanisms both in vitro and in vivo . Finally, untargeted LC-MS/MS analysis was performed to understand which metabolites are produced and released by tomato roots after plant-bacteria interaction occurs. Results This study indicates that herbal formulas that could regulate the composition and proportion of gut microbiota have a positive effect in three stages (perioperative, postoperative, and advanced) of GC and CRC. They could promote the recovery of postoperative gastrointestinal function, increase tumor response, improve performance status, and reduce the incidence of adverse events. Herbal formulas exerted anti-cancer efficacy through multiple mechanisms and pathways; among them, the regulation of gut microbiota has not been paid enough attention. To further support the conclusion and better understand the role of gut microbiota in the treatment of GC and CRC, more rigorously designed, large-scale, and multicenter RCTs that focus on herbal formulas and gut microbiota are needed in the future. Discussion Together, these results indicated that tomato plant protection against Fol is consistent with DEF17 through exudate-mediated modulation, highlighting a gap between in vitro antagonism and in planta efficacy.
Mattei et al. (Wed,) studied this question.