Exploring rhizobacteria-induced molecular pathways in Solanum lycopersicum

Giulia Ghirardello ¹, Rosalba Cipriani ¹, Sebastiano Nigris ¹, Barbara Baldan ¹

Università degli Studi di Padova ¹

Plants cohabit and interact with diverse soil microorganisms, that are archaea, bacteria, fungi, and protists, which form the root microbiota. These communities play a pivotal role in enhancing plant growth through improved nutrient uptake, immunity, and stress tolerance. Here, we examine the role of bacterial species isolated from a commercial compost (SESA s.p.a.) on Solanum lycopersicum cv. Micro-Tom growth and health. Firstly, we identified six main bacterial species from the culturable microbiota of the compost, belonging to Bacillus, Kocuria, Glutamicibacter and Microbacterium genera. Tests for their plant growth-promoting traits revealed their capacity to solubilize phosphorus, produce siderophores and synthesise auxin. The tomato seedlings were grown in vitro and inoculated with single bacterial species to investigate the early plant responses to colonisation through molecular and microscopic techniques. RTqPCR and RNAseq analysis of the plant transcriptome highlighted a specificity in the expression profile of genes representing pathways involved in plant-microbe interplays, such as flavonoid biosynthesis and ethylene production, as well as the immunity system related to the different bacterial species. Moreover, the bacteria expressing fluorescent-tag proteins enabled their tracking through tomato plant tissues and organs by confocal microscopy. Finally, a preliminary analysis of the metabolomic profile induced in tomato root and shoot tissues and exudates shows the signalling molecules and metabolites produced by the interaction. This study contributes to deciphering the molecular signalling behind the interactions between plants and beneficial bacteria in the context of the promotion of sustainable agriculture practices proposed by the European Union within the EU Sustainable Goals 2030.

Main author career stage: PhD student

Contribution type: Talk

First choice session: 2. Ecology

Second choice session: 5. Genetics, genomics, and bioinformatics