Light plays a key role in the modulation of heat shock response in the cyanobacterium Synechocystis sp. PCC 6803

Asadulghani,; Suzuki, Yukiko; Nakamoto, Hitoshi

doi:10.1016/s0006-291x(03)01085-4

Cited by 34 publications

(31 citation statements)

References 26 publications

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“…Additional cellular protection under PSII light is provided by HSPs. A role for HSPs in cellular protection under PSII light is consistent with earlier results obtained in Synechocystis suggesting that the transcription of HSP genes is induced in response to a reduced state of PQ and to oxidative stress (Glatz et al, 1997;Asadulghani et al, 2003;Singh et al, 2003;Li et al, 2004). Similarly, the TrxM/NTR system and HLIPs appear to protect cellular functions under PSI light (Fig.…”

Section: Discussionsupporting

confidence: 90%

“…Changes in transcript levels of the sll1384 gene by PSI light could be seen within 15 min of the onset of illumination and remained high throughout the duration of illumination. Induction of expression of several HSP genes during heat shock in cyanobacteria is known to be modulated by light (Glatz et al, 1997;Asadulghani et al, 2003); however, to our knowledge, expression of HSP genes has not been previously shown to be regulated by illumination with a specific spectrum of light.…”

Section: Cellular Processes Responsive To Psii Lightmentioning

confidence: 79%

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A Systems-Level Analysis of the Effects of Light Quality on the Metabolism of a Cyanobacterium

Singh

Bhattacharyya-Pakrasi

Elvitigala

et al. 2009

Plant Physiology

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Photosynthetic organisms experience changes in light quantity and light quality in their natural habitat. In response to changes in light quality, these organisms redistribute excitation energy and adjust photosystem stoichiometry to maximize the utilization of available light energy. However, the response of other cellular processes to changes in light quality is mostly unknown. Here, we report a systematic investigation into the adaptation of cellular processes in Synechocystis species PCC 6803 to light that preferentially excites either photosystem II or photosystem I. We find that preferential excitation of photosystem II and photosystem I induces massive reprogramming of the Synechocystis transcriptome. The rewiring of cellular processes begins as soon as Synechocystis senses the imbalance in the excitation of reaction centers. We find that Synechocystis utilizes the cyclic photosynthetic electron transport chain for ATP generation and a major part of the respiratory pathway to generate reducing equivalents and carbon skeletons during preferential excitation of photosystem I. In contrast, cytochrome c oxidase and photosystem I act as terminal components of the photosynthetic electron transport chain to produce sufficient ATP and limited amounts of NADPH and reduced ferredoxin during preferential excitation of photosystem II. To overcome the shortage of NADPH and reduced ferredoxin, Synechocystis preferentially activates transporters and acquisition pathways to assimilate ammonia, urea, and arginine over nitrate as a nitrogen source. This study provides a systematic analysis of cellular processes in cyanobacteria in response to preferential excitation and shows that the cyanobacterial cell undergoes significant adjustment of cellular processes, many of which were previously unknown.

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Section: Discussionsupporting

confidence: 90%

Section: Cellular Processes Responsive To Psii Lightmentioning

confidence: 79%

A Systems-Level Analysis of the Effects of Light Quality on the Metabolism of a Cyanobacterium

Singh

Bhattacharyya-Pakrasi

Elvitigala

et al. 2009

Plant Physiology

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“…In the unicellular adiazotrophic cyanobacterium Synechocystis sp. PCC6803, the two hsp60 genes show differential expression in response to heat stress and lightdark cycles (Asadulghani et al, 2003;Glatz et al, 1997;Kovacs et al, 2001;Mary et al, 2004) as well as photosynthetic electron transport (Glatz et al, 1997), or during exposure to UV or oxidative stress (Chitnis & Nelson, 1991). Functional differences in the two Hsp60 proteins have been observed in the complementation of the E. coli groEL44 mutant by the groESL operon and cpn60 gene of Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

Nitrogen status and heat-stress-dependent differential expression of the cpn60 chaperonin gene influences thermotolerance in the cyanobacterium Anabaena

Rajaram

Apte

2008

Microbiology

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“…This might apply to cph2 KO, which is characterized by a higher phycocyanin content compared with the wild type. Heat-induced redox imbalances within the ETC, particularly when combined with photons in excess of use capacity, may result in the generation of reactive oxygen species (Glatz et al, 1999;Asadulghani et al, 2003) and consequent membrane damage. Moreover, the redox state of components of the ETC, preferably the PQ pool, acts as a regulator of gene expression in Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

Cyanobacterial Phytochrome2 Regulates the Heterotrophic Metabolism and Has a Function in the Heat and High-Light Stress Response

et al. 2014

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Cyanobacteria combine the photosynthetic and respiratory electron transport in one membrane system, the thylakoid membrane. This feature requires an elaborate regulation mechanism to maintain a certain redox status of the electron transport chain, hence allowing proper photosynthetic and respiratory energy metabolism. In this context, metabolic adaptations, as seen in the light-todark and dark-to-light transitions, are particularly challenging. However, the molecular basis of the underlying regulatory mechanisms is not well-understood. Here, we describe a function of cyanobacterial phytochrome2 (Cph2), a phytochrome of the cyanobacterial model system Synechocystis sp. PCC 6803, in regulation of the primary energy metabolism. When cells are shifted from photoautotrophic planktonic growth to light-activated heterotrophic growth and biofilm initiation, knockout of Cph2 results in impaired growth, a decrease in the activity of Glc-6-P dehydrogenase, a decrease of the transcript abundance/activity of cytochromec-oxidase, and slower phycocyanin degradation. Measurements of the plastoquinone reduction confirm an impaired heterotrophic metabolism in the cph2 knockout. When cells that were adapted to heterotrophic metabolism are shifted back to light conditions, the knockout of Cph2 results in an altered photosystem II chlorophyll fluorescence induction curve, which is indicative of an impaired redox balance of the electron transport chain. Moreover, Cph2 plays a role in the heat and high-light stress response, particularly under photomixotrophic conditions. Our results show a function of Cph2 in the adaptation of the primary energy metabolism to changing trophic conditions. The physiological role of Cph2 in biofilm formation is discussed.

show abstract

Light plays a key role in the modulation of heat shock response in the cyanobacterium Synechocystis sp. PCC 6803

Cited by 34 publications

References 26 publications

A Systems-Level Analysis of the Effects of Light Quality on the Metabolism of a Cyanobacterium

A Systems-Level Analysis of the Effects of Light Quality on the Metabolism of a Cyanobacterium

Nitrogen status and heat-stress-dependent differential expression of the cpn60 chaperonin gene influences thermotolerance in the cyanobacterium Anabaena

Cyanobacterial Phytochrome2 Regulates the Heterotrophic Metabolism and Has a Function in the Heat and High-Light Stress Response

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