Transcriptional organization and regulation of the<i>Pseudomonas putida</i>flagellar system

Leal-Morales, Antonio; Pulido-Sánchez, Marta; López-Sánchez, Aroa; Govantes, Fernando

doi:10.1101/2021.08.29.457346

Cited by 3 publications

(2 citation statements)

References 98 publications

(180 reference statements)

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“…Hence, the FleQ bEBP that interacts with RpoN to drive an open complex formation domain is also involved in the regulation of the K1-T6SS. This transcription factor has previously been described to activate several genes, importantly flagellar genes, and by binding to c-di-GMP, derepresses the expression of biofilm component genes [75,76]. As expected for a bEBP of RpoN, the K1-T6SS was induced in the absence of FleQ with a slightly higher level of transcription than that observed in the rpoN mutant background (Fig.…”

Section: Discussionsupporting

confidence: 60%

Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster

et al. 2023

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The type VI secretion system (T6SS) is an antimicrobial molecular weapon that is widespread in Proteobacteria and offers competitive advantages to T6SS-positive micro-organisms. Three T6SSs have recently been described in Pseudomonas putida KT2440 and it has been shown that one, K1-T6SS, is used to outcompete a wide range of phytopathogens, protecting plants from pathogen infections. Given the relevance of this system as a powerful and innovative mechanism of biological control, it is critical to understand the processes that govern its expression. Here, we experimentally defined two transcriptional units in the K1-T6SS cluster. One encodes the structural components of the system and is transcribed from two adjacent promoters. The other encodes two hypothetical proteins, the tip of the system and the associated adapters, and effectors and cognate immunity proteins, and it is also transcribed from two adjacent promoters. The four identified promoters contain the typical features of σ 70 -dependent promoters. We have studied the expression of the system under different conditions and in a number of mutants lacking global regulators. P. putida K1-T6SS expression is induced in the stationary phase, but its transcription does not depend on the stationary σ factor RpoS. In fact, the expression of the system is indirectly repressed by RpoS. Furthermore, it is also repressed by RpoN and the transcriptional regulator FleQ, an enhancer-binding protein typically acting in conjunction with RpoN. Importantly, expression of the K1-T6SS gene cluster is positively regulated by the GacS–GacA two-component regulatory system (TCS) and repressed by the RetS sensor kinase, which inhibits this TCS. Our findings identified a complex regulatory network that governs T6SS expression in general and P. putida K1-T6SS in particular, with implications for controlling and manipulating a bacterial agent that is highly relevant in biological control.

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Section: Discussionsupporting

confidence: 60%

Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster

et al. 2023

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“…It is yet unclear if this mode of regulation also applies to other bacteria. Transcriptional studies on different species identified genes that appear to be constitutively transcribed, e.g, the fliHIJ gene cluster in Pseudomonas putida (Leal‐Morales et al, 2022) or flgA and fliEFGHIJ in Vibrio campbellii (Petersen et al, 2021). Also in P. aeruginosa , similar genes and operons as in S. putrefaciens ( fliLMNOPQR‐flhB; fleN‐fliA ) are only slightly regulated at the transcriptional level (Dasgupta et al, 2003), suggesting that the proteins may be permanently present.…”

Section: Discussionmentioning

confidence: 99%

FlrA‐independent production of flagellar proteins is required for proper flagellation in Shewanella putrefaciens

Schwan

Khaledi

Willger

et al. 2022

Molecular Microbiology

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Many bacterial species are able to synthesize flagella, long proteinaceous helical fibres that extend from the cell's surface. Rotation of the flagellar helix, mediated by a membrane-embedded motor, enables efficient active movement of the cell through liquid environments (swimming) or across surfaces (swarming) (Kearns, 2010;Thormann et al., 2022;Wadhwa & Berg, 2022). In addition, the flagellum can serve as an adhesive or pathogenicity factor or as a sensor the bacteria use to determine environmental conditions such as viscosity or surface wetness (Chaban et al., 2015;Laventie & Jenal, 2020). The flagellum is an intricate nanomachine, which -in its general design -is well-conserved between different bacterial species. It consists of the helical filament, the cell envelope-embedded basal body housing the rotary motor and a type III export apparatus, and a universal joint structure, the hook, which connects the motor and filament (Figure 1a) (Johnson et al., 2021;Tan et al., 2021). The whole structure is formed from about 20 different protein building blocks with different stoichiometries ranging from one to nine copies, e.g. for parts of the flagellar type III export system (fT3SS), to many thousands of the main filament building block, the flagellin

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The Regulatory Hierarchy Following Signal Integration by the CbrAB Two-Component System: Diversity of Responses and Functions

Monteagudo‐Cascales

Santero

Canosa

2022

Genes

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CbrAB is a two-component system, unique to bacteria of the family Pseudomonaceae, capable of integrating signals and involved in a multitude of physiological processes that allow bacterial adaptation to a wide variety of varying environmental conditions. This regulatory system provides a great metabolic versatility that results in excellent adaptability and metabolic optimization. The two-component system (TCS) CbrA–CbrB is on top of a hierarchical regulatory cascade and interacts with other regulatory systems at different levels, resulting in a robust output. Among the regulatory systems found at the same or lower levels of CbrAB are the NtrBC nitrogen availability adaptation system, the Crc/Hfq carbon catabolite repression cascade in Pseudomonas, or interactions with the GacSA TCS or alternative sigma ECF factor, such as SigX. The interplay between regulatory mechanisms controls a number of physiological processes that intervene in important aspects of bacterial adaptation and survival. These include the hierarchy in the use of carbon sources, virulence or resistance to antibiotics, stress response or definition of the bacterial lifestyle. The multiple actions of the CbrAB TCS result in an important competitive advantage.

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Transcriptional organization and regulation of thePseudomonas putidaflagellar system

Cited by 3 publications

References 98 publications

Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster

Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster

FlrA‐independent production of flagellar proteins is required for proper flagellation in Shewanella putrefaciens

The Regulatory Hierarchy Following Signal Integration by the CbrAB Two-Component System: Diversity of Responses and Functions

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