Artículo
Depletion of m-type thioredoxin impairs photosynthesis, carbon fixation, and oxidative stress in cyanobacteria
Autor/es | Mallén Ponce, Manuel J.
Huertas Romera, María José Sánchez Riego, Ana María Florencio Bellido, Francisco Javier |
Departamento | Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular |
Fecha de publicación | 2021 |
Fecha de depósito | 2022-05-23 |
Publicado en |
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Resumen | Thioredoxins (Trxs) are disulfide oxidoreductases that regulate many biological processes. The m-type thioredoxin (TrxA) is the only Trx present in all oxygenic photosynthetic organisms. Extensive biochemical and proteomic ... Thioredoxins (Trxs) are disulfide oxidoreductases that regulate many biological processes. The m-type thioredoxin (TrxA) is the only Trx present in all oxygenic photosynthetic organisms. Extensive biochemical and proteomic analyses have identified many TrxA target proteins in different photosynthetic organisms. However, the precise function of this essential protein in vivo is still poorly known. In this study, we generated a conditional Synechocystis sp. PCC 6803 mutant strain (STXA2) using an on-off promoter that is able to survive with only 2% of the TrxA level of the wild-type (WT) strain. STXA2 characterization revealed that TrxA depletion results in growth arrest and pronounced impairment of photosynthesis and the Calvin–Benson–Bassham (CBB) cycle. Analysis of the in vivo redox state of the bifunctional enzyme fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase showed higher levels of oxidation that affected enzyme activity in STXA2. This result implies that TrxA-mediated redox regulation of the CBB cycle is conserved in both cyanobacteria and chloroplasts, although the targets have different evolutionary origins. The STXA2 strain also accumulated more reactive oxygen species and was more sensitive to oxidative stress than the WT. Analysis of the in vivo redox state of 2-Cys peroxiredoxin revealed full oxidation, corresponding with TrxA depletion. Overall, these results indicate that depletion of TrxA in STXA2 greatly alters the cellular redox state, interfering with essential processes such as photosynthetic machinery operativity, carbon assimilation, and oxidative stress response. The TrxA regulatory role appears to be conserved along the evolution of oxygenic photosynthetic organisms. |
Agencias financiadoras | Agencia Estatal de Investigación. España Ministerio de Economía y Competitividad (MINECO). España Junta de Andalucía European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER) |
Identificador del proyecto | PID2019-104513GB-I00/AEI/10.13039/501100011033
BIO2016-75634-P BIO-284 |
Cita | Mallén Ponce, M.J., Huertas Romera, M.J., Sánchez Riego, A.M. y Florencio Bellido, F.J. (2021). Depletion of m-type thioredoxin impairs photosynthesis, carbon fixation, and oxidative stress in cyanobacteria. Plant Physiology, 187 (3), 1325-1340. |
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