Polyamine metabolism in microorganisms plays a crucial role in their growth, ifferentiation, and pathogenesis. The concentration of these polycationic molecules, such as putrescine and spermidine, is finely regulated through the modulation of their synthesis, transport, and degradation pathways. Our aim is to deepen our understanding of the mechanisms that regulate the proteins involved in bacterial polyamine metabolism and their influence on pathogenesis and tolerance to various stresses. To achieve this, we study Pectobacterium versatile (necrotrophic) and Pseudomonas syringae (hemibiotrophic), two phytopathogenic bacteria with contrasting infection strategies. Their comparison will help elucidate the role of polyamines in pathogens establishing different interactions with the plant host and their relevance in bacterial virulence.

Gene silencing in bacteria is a regulatory mechanism based on the interference or degradation of specific mRNAs by small RNAs (sRNAs). In addition to their role in endogenous regulation, some sRNAs are secreted into the environment and taken up by ther bacteria, acting as key mediators in intercellular communication. Our objective is to investigate antibacterial gene silencing (ABGS) as an innovative strategy for the control of plant diseases. To do so, we will evaluate the impact of these biocompounds on processes associated with the pathogenesis of phytopathogenic bacteria, using both sRNAs previously described in the literature and others designed using machine learning models. These studies will clarify the role of sRNAs in bacterial virulence and will lay the foundations for
their application in biotechnological control strategies.

Horticultural production plays a significant role in global agricultural output, ranking second after cereals. Some of the main challenges associated with horticultural production include the unsustainable cultural practices used in vegetable farming, which threaten both the system’s sustainability and the environment, as well as the high incidence of diseases and pests. These issues drive the search for alternatives to traditional practices that are more Compared to chemical pesticides and fertilizers, microbial inoculants offer several advantages: they are safer, cause less environmental damage, and potentially pose a lower risk to human health. They are effective in small quantities, self-replicate, and are "ecologically regulated" both by the plant and native microbial communities. Additionally, they do not induce resistance in the target pathogen and can be used in both conventional and integrated pest management systems.
Biological control of plant pathogens using antagonistic bacteria is a promising strategy for plant health management. In this context, endophytic bacteria have gained significant attention in recent years due to their potential for developing various biotechnological applications in agriculture.
The main objective of this research is to obtain a biological control agent against various agriculturally important diseases, such as black rot (caused by the bacterium Xanthomonas campestris pv. campestris), white mold (caused by the fungus Sclerotinia sclerotiorum), and blackleg (caused by Leptosphaeria maculans) in horticulturally significant Brassicaceae crops, such as cabbage and broccoli. This study focuses not only on the use of whole microorganisms but also on different antimicrobial compounds produced by endophytic bacteria.
We employ various microbiologic, genomic, metabolomic, and physiological approaches to select and determine biocontrol efficacy and enhance the chances of success using beneficial microorganisms.

Pombo MA, Rosli HG, Maiale S, Elliot C, Stieben ME, Romero FM, Garriz A, Ruiz OA, Idnurum A, Rossi FR. Unveiling the virulence mechanism of Leptosphaeria maculans in the Brassica napus interaction: the key role of sirodesmin PL in the induction of cell death. Journal of Experimental Botany, 76, 6, 1767–1783. 2025. https://doi.org/10.1093/jxb/erae498