Evidence for weak interaction between phytochromes Agp1 and Agp2 from <i>Agrobacterium fabrum</i>

Xue, Peng; Kurdi, Afaf El; Köhler, Annette G.; Ma, Hao; Kaeser, Gero; Ali, Arin; Fischer, Reinhard; Krauß, Norbert; Lamparter, Tilman

doi:10.1002/1873-3468.13376

Cited by 9 publications

(21 citation statements)

References 58 publications

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“…In conjugation and plant infection, dark action of phytochrome is reduced in the light. This pattern correlates with the histidine autokinase activity of Agp1 (3), but not with that of Agp2 (34). Phosphotransfer is thus a possible initial signal transmission mechanism, but cannot be the only one.…”

Section: Discussionmentioning

confidence: 66%

“…One could imagine that Agp1 reverts the light response of Agp2. Since there is an interaction between both proteins at lease in vitro (34), several molecular scenarios seem possible to explain such an impact of one phytochrome on the other.…”

Section: Resultsmentioning

confidence: 99%

“…With this mutant, plant transformation was high in the light and low in the dark ( Figure 6 ). Both A. fabrum phytochromes interact in vitro (34), so Agp1 could act on Agp2 either by modulating other protein interactions or by covalent modifications. Phylogenetically, Agp1 and Agp2 are rather unrelated phytochromes.…”

Section: Discussionmentioning

confidence: 99%

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Phytochrome mediated responses inAgrobacterium fabrum: growth, swimming, plant infection and interbacterial competition

Xue

Bai

Rottwinkel

et al. 2020

Preprint

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The soil bacterium Agrobacterium fabrum C58 infects plants by a unique 15 DNA transfer mechanism. A. fabrum has two phytochrome photoreceptors, Agp1 and Agp2. We 16 found that DNA transfer into plants by A. fabrum is down regulated by light and that 17 phytochrome knockout mutants have diminished DNA transfer rates. The regulation pattern 18 matches with that of bacterial conjugation reported earlier. Growth, swimming and interbacterial 19 competition were also affected in phytochrome knockout mutants, although these effects were 20 often not affected by light. We can thus distinguish between light-regulated and light-independent 21 phytochrome responses. In microarray studies, transcription of only 4 genes was affected by 22 light, indicating that most light responses are regulated post-transcriptionally. In a mass 23 spectrometery-based proteomic study, 24 proteins were different between light and dark grown 24 bacteria, whereas 382 proteins differed between wild type and phytochrome knockout mutants, 25 pointing again to light-dependent and light-independent roles of Agp1 and Agp2. 26 27 stranded DNA is covalently attached to the protein that makes the nick, which is VirD2 (21) in A. 59 fabrum plant infection and TraA (22) in conjugation. During conjugation, the entire plasmid is 60 transferred. The complex of protein and single-strand DNA is transferred through pili formed by 61 the type IV secretion system into the target cells. 62We also tested the impact of phytochromes in A. fabrum on growth, motility, and 63 interbacterial competition and also performed microarray and proteome studies. These data show 64 that protein levels are affected for few gene products and suggests regulatory mechanisms 65 independent on transcription or translation. On the organismal level and on the level of single 66 proteins, we found phytochrome effects that are light dependent and such that are light 67 independent. 68

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Section: Discussionmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 99%

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Phytochrome mediated responses inAgrobacterium fabrum: growth, swimming, plant infection and interbacterial competition

Xue

Bai

Rottwinkel

et al. 2020

Preprint

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“…The Pr/Pfr pattern is comparable with several other bacterial phytochromes such as Cph1 ( Yeh et al, 1997 ). In our hands, there was no autophosphorylation of Agp2 wild type only mutants in which the Asp residue of the response regulator was replaced showed Pr/Pfr independent autophosphorylation ( Xue et al, 2019 ). Interesting temperature effects – the kinase activity decreased with increasing temperature – were found for Agp1, leading to the suggestion that Agp1 could also act as a temperature sensor ( Njimona and Lamparter, 2011 ; Njimona et al, 2014 ).…”

Section: Overviewmentioning

confidence: 69%

Phytochromes in Agrobacterium fabrum

et al. 2021

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The focus of this review is on the phytochromes Agp1 and Agp2 of Agrobacterium fabrum. These are involved in regulation of conjugation, gene transfer into plants, and other effects. Since crystal structures of both phytochromes are known, the phytochrome system of A. fabrum provides a tool for following the entire signal transduction cascade starting from light induced conformational changes to protein interaction and the triggering of DNA transfer processes.

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“…The bacterial DNA encodes enzymes for synthesis of auxin, cytokinin, and opine, the latter compound a nutrition source for the bacterium. The BphPs Agp1 and Agp2 from the Agrobacterium fabrum strain C58 have been extensively studied at the molecular level and partially in vivo [74][75][76]. Agp1 is a canonical BphP, where the dark-adapted state is in the Pr form, while Agp2 is a bathy-phy, stable in the dark as the Pfr form [77].…”

Section: Photoresponses and Photoreceptors In Plant-associated Bacteriamentioning

confidence: 99%

A light life together: photosensing in the plant microbiota

Losi

Gärtner

2021

Photochem Photobiol Sci

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Bacteria and fungi of the plant microbiota can be phytopathogens, parasites or symbionts that establish mutually advantageous relationships with plants. They are often rich in photoreceptors for UVA–Visible light, and in many cases, they exhibit light regulation of growth patterns, infectivity or virulence, reproductive traits, and production of pigments and of metabolites. In addition to the light-driven effects, often demonstrated via the generation of photoreceptor gene knock-outs, microbial photoreceptors can exert effects also in the dark. Interestingly, some fungi switch their attitude towards plants in dependence of illumination or dark conditions in as much as they may be symbiotic or pathogenic. This review summarizes the current knowledge about the roles of light and photoreceptors in plant-associated bacteria and fungi aiming at the identification of common traits and general working ideas. Still, reports on light-driven infection of plants are often restricted to the description of macroscopically observable phenomena, whereas detailed information on the molecular level, e.g., protein–protein interaction during signal transduction or induction mechanisms of infectivity/virulence initiation remains sparse. As it becomes apparent from still only few molecular studies, photoreceptors, often from the red- and the blue light sensitive groups interact and mutually modulate their individual effects. The topic is of great relevance, even in economic terms, referring to plant-pathogen or plant-symbionts interactions, considering the increasing usage of artificial illumination in greenhouses, the possible light-regulation of the synthesis of plant-growth stimulating substances or herbicides by certain symbionts, and the biocontrol of pests by selected fungi and bacteria in a sustainable agriculture.

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Evidence for weak interaction between phytochromes Agp1 and Agp2 from Agrobacterium fabrum

Cited by 9 publications

References 58 publications

Phytochrome mediated responses inAgrobacterium fabrum: growth, swimming, plant infection and interbacterial competition

Phytochrome mediated responses inAgrobacterium fabrum: growth, swimming, plant infection and interbacterial competition

Phytochromes in Agrobacterium fabrum

A light life together: photosensing in the plant microbiota

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