Development and utilization of“liquid sunshine”could be one of key solutions to deal with the issues of fossil fuel depletion and increasing carbon dioxide.Cyanobacteria are the only prokaryotes capable of performin...Development and utilization of“liquid sunshine”could be one of key solutions to deal with the issues of fossil fuel depletion and increasing carbon dioxide.Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis,and their activity accounts for~25%of the total carbon fixation on earth.More importantly,besides their traditional roles as primary producers,cyanobacteria could be modified as“photosynthetic cell factories”to produce renewable fuels and chemicals directly from CO_(2) driven by solar energy,with the aid of cutting-edging synthetic biology technology.Towards their large-scale biotechnological application in the future,many challenges still need to be properly addressed,among which is cyanobacterial cell factories inevitably suffer from high light(HL)stress during large-scale outdoor cultivation,resulting in photodamage and even cell death,limiting their productivity.In this review,we critically summarized recent progress on deciphering molecular mechanisms to HL and developing HL-tolerant chassis in cyanobacteria,aiming at facilitating construction of HLresistant chassis and promote the future application of the large-scale outdoor cultivation of cyanobacterial cell factories.Finally,the future directions on cyanobacterial chassis engineering were discussed.展开更多
High-light stress strongly limits agricultural production in subtropical and tropical regions owing to photo-oxidative damage,decreased growth,and decreased yield.Here,we investigated whether beneficial mi-crobes can p...High-light stress strongly limits agricultural production in subtropical and tropical regions owing to photo-oxidative damage,decreased growth,and decreased yield.Here,we investigated whether beneficial mi-crobes can protect plants under high-light stress.We found that Enterobacter sp.SA187(SA187)supports the growth of Arabidopsis thaliana under high-light stress by reducing the accumulation of reactive oxygen species and maintaining photosynthesis.Under high-light stress,SA187 triggers dynamic changes in the expression of Arabidopsis genes related to fortified iron metabolism and redox regulation,thereby enhancing the antioxidative glutathione/glutaredoxin redox system of the plant.Genetic analysis showed that the enhancement of iron and sulfur metabolism by SA187 is coordinated by ethylene signaling.In sum-mary,beneficial microbes could be an effective and inexpensive means of enhancing high-light-stress tolerance in plants.展开更多
The genome of unicellular green alga Chlamydomonas reinhardtii contains four genes encoding B-type methionine sulfoxide reductases, MSRBI.1, MSRB1.2, MSRB2.1, and MSRB2.2, with functions largely unknown. To understand...The genome of unicellular green alga Chlamydomonas reinhardtii contains four genes encoding B-type methionine sulfoxide reductases, MSRBI.1, MSRB1.2, MSRB2.1, and MSRB2.2, with functions largely unknown. To understand the cell defense system mediated by the methionine suifoxide reductases in Chlamydomonas, we analyzed expression and physiological roles of the MSRBs under different abiotic stress conditions using immunoblotting and quantitative polymerase chain reaction （PCR） analyses. We showed that the MSRB2.2 protein was accumulated in cells treated with high light （1,300 μE-/m2 per s）, whereas MSRBI.1 was accumulated in the cells under 1 mmol/L H2O2 treatment or sulfur depletion. We observed that the cells with the MSRB2.2 knockdown and overexpression displayed increased and decreased sensitivity to high light, respectively, based on in situ chlorophyll a fluorescence measures. We also observed that the cells with the MSRBI.1 knockdown and overexpression displayed decreased and increased tolerance to sulfur-depletion and oxidative stresses, respectively, based on growth and H2- producing performance. The physiological implications revealed from the experimental data highlight the importance of MSRB2.2 and MSRBI.1 in protecting Chlamydomonas cells against adverse conditions such as high-light, sulfur-depletion, and oxidative stresses.展开更多
基金This research was supported by grants from the National Key Research and Development Program of China(No.2019YFA0904600,2018YFA0903600,2020YFA0906800 and 2018YFA0903000)the National Natural Science Foundation of China(No.31770035,31972931,91751102,31770100,31901017,31901016,32070083 and 21621004)Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(No.TSBICIP-KJGG-007).
文摘Development and utilization of“liquid sunshine”could be one of key solutions to deal with the issues of fossil fuel depletion and increasing carbon dioxide.Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis,and their activity accounts for~25%of the total carbon fixation on earth.More importantly,besides their traditional roles as primary producers,cyanobacteria could be modified as“photosynthetic cell factories”to produce renewable fuels and chemicals directly from CO_(2) driven by solar energy,with the aid of cutting-edging synthetic biology technology.Towards their large-scale biotechnological application in the future,many challenges still need to be properly addressed,among which is cyanobacterial cell factories inevitably suffer from high light(HL)stress during large-scale outdoor cultivation,resulting in photodamage and even cell death,limiting their productivity.In this review,we critically summarized recent progress on deciphering molecular mechanisms to HL and developing HL-tolerant chassis in cyanobacteria,aiming at facilitating construction of HLresistant chassis and promote the future application of the large-scale outdoor cultivation of cyanobacterial cell factories.Finally,the future directions on cyanobacterial chassis engineering were discussed.
基金King Abdullah University of Science and Technology(KAUST)base fund for H.H.no.BAS/1/1062-01-01.J.-P.R.was supported by the Agropolis Fondation(Flagship Project CalClim grant no.1802-002).
文摘High-light stress strongly limits agricultural production in subtropical and tropical regions owing to photo-oxidative damage,decreased growth,and decreased yield.Here,we investigated whether beneficial mi-crobes can protect plants under high-light stress.We found that Enterobacter sp.SA187(SA187)supports the growth of Arabidopsis thaliana under high-light stress by reducing the accumulation of reactive oxygen species and maintaining photosynthesis.Under high-light stress,SA187 triggers dynamic changes in the expression of Arabidopsis genes related to fortified iron metabolism and redox regulation,thereby enhancing the antioxidative glutathione/glutaredoxin redox system of the plant.Genetic analysis showed that the enhancement of iron and sulfur metabolism by SA187 is coordinated by ethylene signaling.In sum-mary,beneficial microbes could be an effective and inexpensive means of enhancing high-light-stress tolerance in plants.
基金supported by the Ministry of Science and Technology of China (2009CB220000)Chinese Ministry of Agriculture (2009ZX08009-121B)the Chinese Academy of Sciences
文摘The genome of unicellular green alga Chlamydomonas reinhardtii contains four genes encoding B-type methionine sulfoxide reductases, MSRBI.1, MSRB1.2, MSRB2.1, and MSRB2.2, with functions largely unknown. To understand the cell defense system mediated by the methionine suifoxide reductases in Chlamydomonas, we analyzed expression and physiological roles of the MSRBs under different abiotic stress conditions using immunoblotting and quantitative polymerase chain reaction （PCR） analyses. We showed that the MSRB2.2 protein was accumulated in cells treated with high light （1,300 μE-/m2 per s）, whereas MSRBI.1 was accumulated in the cells under 1 mmol/L H2O2 treatment or sulfur depletion. We observed that the cells with the MSRB2.2 knockdown and overexpression displayed increased and decreased sensitivity to high light, respectively, based on in situ chlorophyll a fluorescence measures. We also observed that the cells with the MSRBI.1 knockdown and overexpression displayed decreased and increased tolerance to sulfur-depletion and oxidative stresses, respectively, based on growth and H2- producing performance. The physiological implications revealed from the experimental data highlight the importance of MSRB2.2 and MSRBI.1 in protecting Chlamydomonas cells against adverse conditions such as high-light, sulfur-depletion, and oxidative stresses.
