Co-expression analysis, proteomic and metabolomic study on the impact of a Deg/HtrA protease triple mutant in Synechocystis sp. PCC 6803 exposed to temperature and high light stress

Photosystem II (PSII) is prone to irreversible light–induced damage, with the D1 polypeptide a major target. Repair processes operate in the cell to replace a damaged D1 subunit within the complex with a newly synthesized copy. As yet, the molecular details of PSII repair are relatively obscure despite the critical importance of this process for maintaining PSII activity and cell viability. We are using the cyanobacterium Synechocystis sp. PCC 6803 to identify the various proteases and chaperones involved in D1 turnover in vivo . Two families of proteases are being studied: the FtsH family (four members) of Zn 2+ –activated nucleotide–dependent proteases; and the HtrA (or DegP) family (three members) of serine–type proteases. In this paper, we report the results of our studies on a triple mutant in which all three copies of the htrA gene family have been inactivated. Growth of the mutant on agar plates was inhibited at high light intensities, especially in the presence of glucose. Oxygen evolution measurements indicated that, under conditions of high light, the rate of synthesis of functional PSII was less in the mutant than in the wild–type. Immunoblotting experiments conducted on cells blocked in protein synthesis further indicated that degradation of D1 was slowed in the mutant. Overall, our observations indicate that the HtrA family of proteases are involved in the resistance of Synechocystis 6803 to light stress and play a part, either directly or indirectly, in the repair of PSII in vivo .

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Lack of digalactosyldiacylglycerol increases the sensitivity ofSynechocystissp. PCC 6803 to high light stress

FEBS Letters ◽

10.1016/j.febslet.2009.01.021 ◽

2009 ◽

Vol 583 (4) ◽

pp. 718-722 ◽

Cited By ~ 25

Author(s):

Naoki Mizusawa ◽

Isamu Sakurai ◽

Naoki Sato ◽

Hajime Wada

Keyword(s):

Light Stress ◽

High Light ◽

High Light Stress ◽

Pcc 6803

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Color-Specific Recovery to Extreme High-Light Stress in Plants

Life ◽

10.3390/life11080812 ◽

2021 ◽

Vol 11 (8) ◽

pp. 812

Author(s):

Débora Parrine ◽

Todd M. Greco ◽

Bilal Muhammad ◽

Bo-Sen Wu ◽

Xin Zhao ◽

...

Keyword(s):

Blue Light ◽

Light Stress ◽

Red Light ◽

Light Treatment ◽

High Light ◽

Mrna Levels ◽

Light Conditions ◽

High Light Stress ◽

General Response ◽

The Impact

Plants pigments, such as chlorophyll and carotenoids, absorb light within specific wavelength ranges, impacting their response to environmental light changes. Although the color-specific response of plants to natural levels of light is well described, extreme high-light stress is still being discussed as a general response, without considering the impact of wavelengths in particular response processes. In this study, we explored how the plant proteome coordinated the response and recovery to extreme light conditions (21,000 µmol m−2 s−1) under different wavelengths. Changes at the protein and mRNA levels were measured, together with the photosynthetic parameters of plants under extreme high-light conditions. The changes in abundance of four proteins involved in photoinhibition, and in the biosynthesis/assembly of PSII (PsbS, PsbH, PsbR, and Psb28) in both light treatments were measured. The blue-light treatment presented a three-fold higher non-photochemical quenching and did not change the level of the oxygen-evolving complex (OEC) or the photosystem II (PSII) complex components when compared to the control, but significantly increased psbS transcripts. The red-light treatment caused a higher abundance of PSII and OEC proteins but kept the level of psbS transcripts the same as the control. Interestingly, the blue light stimulated a more efficient energy dissipation mechanism when compared to the red light. In addition, extreme high-light stress mechanisms activated by blue light involve the role of OEC through increasing PsbS transcript levels. In the proteomics spatial analysis, we report disparate activation of multiple stress pathways under three differently damaged zones as the enriched function of light stress only found in the medium-damaged zone of the red LED treatment. The results indicate that the impact of extreme high-light stress on the proteomic level is wavelength-dependent.

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