Project description:Pseudomonas syringae, a Gram-negative plant pathogen, infects more than 50 crops with its type III secretion system (T3SS) and causes severe economic losses around the world. Although the mechanisms of virulence-associated regulators of P. syringae T3SS have been studied for decades, the crosstalk and network underlying these regulators are still elusive. Previously, we have individually studied a group of T3SS regulators, including AefR, HrpS, and RhpRS. In the present study, we found 4 new T3SS regulator genes (envZ, ompR, tsiS and phoQ) via transposon-mediated mutagenesis. Two-component systems EnvZ and TsiS natively regulate T3SS. In order to uncover the crosstalk between 16 virulence-associated regulators, (including AefR, AlgU, CvsR, GacA, HrpL, HrpR, HrpS, MgrA, OmpR, PhoP, PilR, PsrA, RhpR, RpoN, TsiR and Vfr) in P. syringae, we mapped an intricate network named PSVnet (Pseudomonas syringae Virulence Regulatory Network) by combining differentially expression genes in RNA-seq and binding loci in ChIP-seq of all regulators.
Project description:KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologs of this protein are widespread among bacteria not known to have a circadian physiology. The function, interaction network, and mechanism of action of these KaiC homologs are still largely unknown. Here, we focus on KaiC homologs found in environmental Pseudomonas species. We characterize experimentally the only KaiC homolog present in Pseudomonas putida KT2440 and Pseudomonas protegens CHA0. Through phenotypic assays and transcriptomics, we show that KaiC is involved in osmotic and oxidative stress resistance in P. putida and in biofilm production in both P. putida and P. protegens.
Project description:Pseudomonas aeruginosa is a gram negative, opportunistic pathogen, which is the major cause of corneal infections in India and worldwide. Being categorised in the critical group of antibiotic resistant species, it has prompted significance rise in research to develop alternative therapeutics. One such alternative to combat bacterial infections is antimicrobial peptides (AMPs). This study aims to investigate the role of S100A12, a host defence peptide against PAO1. It was also seen to inhibit the bacterial growth of PAO1 in vitro as seen from the colony forming units. Our study sheds light on how S100A12 impacts Pseudomonas and that it might have the potential to be used as therapeutic intervention in addition to antibiotics in future.