Hydrogen production by indigenous photosynthetic bacterium Rhodopseudomonas palustris WP3–5 using optical fiber-illuminating photobioreactors

ABSTRACT A major route for hydrogen production by purple photosynthetic bacteria is biological nitrogen fixation. Nitrogenases reduce atmospheric nitrogen to ammonia with the concomitant obligate production of molecular hydrogen. However, hydrogen production in the context of nitrogen fixation is a rather inefficient process because about 75% of the reductant consumed by the nitrogenase is used to generate ammonia. In this study we describe a selection strategy to isolate strains of purple photosynthetic bacteria in which hydrogen production is necessary for growth and independent of nitrogen fixation. We obtained four mutant strains of the photosynthetic bacterium Rhodopseudomonas palustris that produce hydrogen constitutively, even in the presence of ammonium, a condition where wild-type cells do not accumulate detectable amounts of hydrogen. Some of these strains produced up to five times more hydrogen than did wild-type cells growing under nitrogen-fixing conditions. Transcriptome analyses of the hydrogen-producing mutant strains revealed that in addition to the nitrogenase genes, 18 other genes are potentially required to produce hydrogen. The mutations that caused constitutive hydrogen production mapped to four different sites in the NifA transcriptional regulator in the four different strains. The strategy presented here can be applied to the large number of diverse species of anoxygenic photosynthetic bacteria that are known to exist in nature to identify strains for which there are fitness incentives to produce hydrogen.

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Efficient hydrogen production using a multi-layered photobioreactor and a photosynthetic bacterium mutant with reduced pigment

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2006.06.019 ◽

2006 ◽

Vol 31 (11) ◽

pp. 1522-1526 ◽

Cited By ~ 48

Author(s):

T KONDO ◽

T WAKAYAMA ◽

J MIYAKE

Keyword(s):

Hydrogen Production ◽

Photosynthetic Bacterium

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Dynamic photocatalytic hydrogen production from ethanol–water mixtures in an optical fiber honeycomb reactor loaded with Au/TiO2

Journal of Catalysis ◽

10.1016/j.jcat.2013.10.025 ◽

2014 ◽

Vol 309 ◽

pp. 460-467 ◽

Cited By ~ 48

Author(s):

Elena Taboada ◽

Inma Angurell ◽

Jordi Llorca

Keyword(s):

Hydrogen Production ◽

Optical Fiber ◽

Photocatalytic Hydrogen Production

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Effects of the deletion of hup genes encoding the uptake hydrogenase on the activity of hydrogen production in the purple photosynthetic bacterium Rubrivivax gelatinosus IL144

The Journal of General and Applied Microbiology ◽

10.2323/jgam.2017.01.003 ◽

2017 ◽

Vol 63 (5) ◽

pp. 274-279 ◽

Cited By ~ 3

Author(s):

Takeshi Sato ◽

Kazuhito Inoue ◽

Hidehiro Sakurai ◽

Kenji V. P. Nagashima

Keyword(s):

Hydrogen Production ◽

Photosynthetic Bacterium ◽

Uptake Hydrogenase ◽

Genes Encoding ◽

Purple Photosynthetic Bacterium ◽

Rubrivivax Gelatinosus

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Rhodopseudomonas palustris quorum sensing molecule pC-HSL induces systemic resistance to TMV infection via up-regulation of NbSIPK/NbWIPK expressions in Nicotiana benthamiana

Phytopathology ◽

10.1094/phyto-05-20-0177-r ◽

2020 ◽

Author(s):

Xiaohua Du ◽

Renyan Huang ◽

Zhuo Zhang ◽

Deyong Zhang ◽

Ju`e Cheng ◽

...

Keyword(s):

Quorum Sensing ◽

Nicotiana Benthamiana ◽

Biological Activities ◽

Plant Immunity ◽

Rhodopseudomonas Palustris ◽

Photosynthetic Bacterium ◽

Homoserine Lactone ◽

Systemic Resistance ◽

Marker Genes ◽

Ros Scavenging

G-negative bacteria produce a myriad of N-acyl-homoserine lactones (AHLs) that can function as quorum sensing (QS) signaling molecules. AHLs are also known to regulate various plant biological activities. p-Coumaroyl-homoserine lactone (pC-HSL) is the only QS molecule produced by a photosynthetic bacterium, Rhodopseudomonas palustris (R. palustris). The role of pC-HSL in the interaction between R. palustris and plant has not been investigated. In this study, we investigated the effect of pC-HSL on plant immunity and have found that this QS molecule can induce a systemic resistance to Tobacco mosaic virus (TMV) infection in Nicotiana benthamiana (N. benthamiana). The results show that pC-HSL treatment can prolong the activation of two mitogen-associated protein kinase (MAPK) genes (i.e., NbSIPK and NbWIPK) and enhance the expression of transcription factor WRKY8 as well as immune response marker genes NbPR1 and NbPR10, leading to an increased accumulation of reactive oxygen species (ROS) in the TMV infected plants. Our results also show that pC-HSL treatment can increase activities of two ROS-scavenging enzymes, POD and SOD. Knockdown of NbSIPK or NbWIPK expression in N. benthamiana plants through VIGS nullified or attenuated pC-HSL-induced systemic resistance, indicating that the functioning of pC-HSL relies on the activity of those two kinases. Meanwhile, pC-HSL pre-treated plants also showed a strong induction of kinase activities of NbSIPK and NbWIPK post TMV inoculation. Taken together, our results demonstrate that pC-HSL treatment results in enhanced plant resistance to TMV infection, which is helpful to uncover the outcome of interaction between R. palustris and its host plants.

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