25-09-2026
Carbohydrate uptake is essential for bacterial survival, adaptation, and metabolic fitness in environmental and host-associated niches. This work investigates ABC transporter systems involved in carbohydrate acquisition in the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.
In B. subtilis, the FrlONM-FrlP complex was shown to mediate uptake of the α-glycated amino acid fructosevaline. FrlP can functionally replace the broadly conserved ATPase MsmX, demonstrating functional redundancy between these energy-providing components. frlP expression is induced by fructosevaline and regulated by the transcriptional repressor FrlR, with additional control by a non-coding RNA. Unlike the widely distributed MsmX, FrlP is mainly restricted to the B. subtilis group, suggesting a role in adaptation to plant-associated environments.
In S. aureus, the MalKEFG ABC transporter was shown to import maltodextrins containing three to seven glucose residues. Genetic analyses indicated that both MalKEFG and the PTS contribute to maltotriose uptake, highlighting cooperation between carbohydrate transport pathways. Its potential role in biofilm formation was also investigated.
Overall, these findings provide new insights into the mechanisms, regulation, and evolutionary adaptation of carbohydrate transport in Gram-positive bacteria and highlight their importance for bacterial fitness in environmental and host-associated niches.
This Thesis was developed at Microbial Genetics Lab at UCIBIO (https://ucibio.pt/research-groups/lab/microbial-genetics), and was supervised by Prof. Isabel de Sá Nogueira and co-supervised bu Prof. Jaime Mota.
Congratulations, Inês!