PHB Biosynthesis Counteracts Redox Stress in Herbaspirillum seropedicae

Batista, Marcelo Bueno; Teixeira, C.S.; Sfeir, Michelle Zibetti Tadra; Alves, Luis Paulo Silveira; Valdameri, Gláucio; Pedrosa, Fábio de Oliveira; Sassaki, Guilherme L.; Steffens, Maria; Souza, Emanuel Maltempi de; Dixon, Ray; Müller-Santos, Marcelo

doi:10.3389/fmicb.2018.00472

Cited by 50 publications

(25 citation statements)

References 48 publications

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“…In the strain Herbaspirillum seropedicae, PHB is able to reduce redoxstress. Hence, PHB could serve as an electron sink to eliminate a surplus of reducing equivalents [11]. A similar behavior has been shown in the anoxygenic phototrophic bacterium Chromatium vinosum: it converts glycogen to PHB (under anerobic, dark metabolism) [12].…”

Section: Introductionmentioning

confidence: 52%

On the Role and Production of Polyhydroxybutyrate (PHB) in the Cyanobacterium Synechocystis sp. PCC 6803

Koch

Berendzen

Forchhammer

2020

Life

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The cyanobacterium Synechocystis sp. PCC 6803 is known for producing polyhydroxybutyrate (PHB) under unbalanced nutrient conditions. Although many cyanobacteria produce PHB, its physiological relevance remains unknown, since previous studies concluded that PHB is redundant. In this work, we try to better understand the physiological conditions that are important for PHB synthesis. The accumulation of intracellular PHB was higher when the cyanobacterial cells were grown under an alternating day–night rhythm as compared to continuous light. In contrast to previous reports, a reduction of PHB was observed when the cells were grown under conditions of limited gas exchange. Since previous data showed that PHB is not required for the resuscitation from nitrogen starvation, a series of different abiotic stresses were applied to test if PHB is beneficial for its fitness. However, under none of the tested conditions did cells containing PHB show a fitness advantage compared to a PHB-free-mutant (ΔphaEC). Additionally, the distribution of PHB in single cells of a population Synechocystis cells was analyzed via fluorescence-activated cell sorting (FACS). The results showed a considerable degree of phenotypic heterogeneity at the single cell level concerning the content of PHB, which was consistent over several generations. These results improve our understanding about how and why Synechocystis synthesizes PHB and gives suggestions how to further increase its production for a biotechnological process.

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Section: Introductionmentioning

confidence: 52%

On the Role and Production of Polyhydroxybutyrate (PHB) in the Cyanobacterium Synechocystis sp. PCC 6803

Koch

Berendzen

Forchhammer

2020

Life

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“…viridis A10.1 plants with H. seropedicae SmR1 and various mutants defective in PHB metabolism (13, 37). Consistent with our previous findings, the inoculation with H.…”

Section: Resultsmentioning

confidence: 99%

Importance of Poly-3-Hydroxybutyrate Metabolism to the Ability of Herbaspirillum seropedicae To Promote Plant Growth

Alves

Amaral

Kim

et al. 2019

Appl Environ Microbiol

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Herbaspirillum seropedicaeis an endophytic bacterium that establishes an association with a variety of plants, such as rice, corn, and sugarcane, and can significantly increase plant growth.H. seropedicaeproduces polyhydroxybutyrate (PHB), stored in the form of insoluble granules. Little information is available on the possible role of PHB in bacterial root colonization or in plant growth promotion. To investigate whether PHB is important for the association ofH. seropedicaewith plants, we inoculated roots ofSetaria viridiswithH. seropedicaestrain SmR1 and mutants defective in PHB production (ΔphaP1, ΔphaP1ΔphaP2, ΔphaC1, and ΔphaR) or mobilization (ΔphaZ1ΔphaZ2). The strains producing large amounts of PHB colonized roots, significantly increasing root area and the number of lateral roots compared to those of PHB-negative strains.H. seropedicaegrows under microaerobic conditions, which can be found in the rhizosphere. When grown under low-oxygen conditions, only the parental strain and ΔphaP2mutant exhibited normal growth. The lack of normal growth under low oxygen correlated with the inability to stimulate plant growth, although there was no effect on the level of root colonization. The data suggest that PHB is produced in the root rhizosphere and plays a role in maintaining normal metabolism under microaerobic conditions. To confirm this, we screened for green fluorescent protein (GFP) expression under the control of theH. seropedicaepromoters of the PHA synthase and PHA depolymerase genes in the rhizosphere. PHB synthesis is active on the root surface and later PHB depolymerase expression is activated.IMPORTANCEThe application of bacteria as plant growth promoters is a sustainable alternative to mitigate the use of chemical fertilization in agriculture, reducing negative economic and environmental impacts. Several plant growth-promoting bacteria synthesize and accumulate the intracellular polymer polyhydroxybutyrate (PHB). However, the role of PHB in plant-bacterium interactions is poorly understood. In this study, applying the C4 model grassSetaria viridisand several mutants in the PHB metabolism of the endophyteHerbaspirillum seropedicaeyielded new findings on the importance of PHB for bacterial colonization ofS. viridisroots. Taken together, the results show that deletion of genes involved in the synthesis and degradation of PHB reduced the ability of the bacteria to enhance plant growth but with little effect on overall root colonization. The data suggest that PHB metabolism likely plays an important role in supporting specific metabolic routes utilized by the bacteria to stimulate plant growth.

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“…PHB is produced by microorganisms in responses to physiologically stressed conditions, especially when nutrients are limited (Ackermann et al, 1995; Batista et al, 2018). In C. hepaticus , PHB might be produced by the condensation of acetyl-CoA to acetoacetyl-CoA and is later converted to acetoacetate, and acetoacetate is then reduced by NADH to R -3-hydroxybutyrate where D-beta-hydroxybutyrate dehydrogenase enzyme catalyzes the reaction (Figure 5).…”

Section: Discussionmentioning

confidence: 99%

Survival Mechanisms of Campylobacter hepaticus Identified by Genomic Analysis and Comparative Transcriptomic Analysis of in vivo and in vitro Derived Bacteria

et al. 2019

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Chickens infected with Campylobacter jejuni or Campylobacter coli are largely asymptomatic, however, infection with the closely related species, Campylobacter hepaticus, can result in Spotty Liver Disease (SLD). C. hepaticus has been detected in the liver, bile, small intestine and caecum of SLD affected chickens. The survival and colonization mechanisms that C. hepaticus uses to colonize chickens remain unknown. In this study, we compared the genome sequences of 14 newly sequenced Australian isolates of C. hepaticus, isolates from outbreaks in the United Kingdom, and reference strains of C. jejuni and C. coli, with the aim of identifying virulence genes associated with SLD. We also carried out global comparative transcriptomic analysis between C. hepaticus recovered from the bile of SLD infected chickens and C. hepaticus grown in vitro. This revealed how the bacteria adapt to proliferate in the challenging host environment in which they are found. Additionally, biochemical experiments confirmed some in silico metabolic predictions. We found that, unlike other Campylobacter sp., C. hepaticus encodes glucose and polyhydroxybutyrate metabolism pathways. This study demonstrated the metabolic plasticity of C. hepaticus, which may contribute to survival in the competitive, nutrient and energy-limited environment of the chicken. Transcriptomic analysis indicated that gene clusters associated with glucose utilization, stress response, hydrogen metabolism, and sialic acid modification may play an important role in the pathogenicity of C. hepaticus. An understanding of the survival and virulence mechanisms that C. hepaticus uses will help to direct the development of effective intervention methods to protect birds from the debilitating effects of SLD.

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PHB Biosynthesis Counteracts Redox Stress in Herbaspirillum seropedicae

Cited by 50 publications

References 48 publications

On the Role and Production of Polyhydroxybutyrate (PHB) in the Cyanobacterium Synechocystis sp. PCC 6803

On the Role and Production of Polyhydroxybutyrate (PHB) in the Cyanobacterium Synechocystis sp. PCC 6803

Importance of Poly-3-Hydroxybutyrate Metabolism to the Ability of Herbaspirillum seropedicae To Promote Plant Growth

Survival Mechanisms of Campylobacter hepaticus Identified by Genomic Analysis and Comparative Transcriptomic Analysis of in vivo and in vitro Derived Bacteria

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