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Luqman M, Shahbaz M, Maqsood MF, Farhat F, Zulfiqar U, Siddiqui MH, Masood A, Aqeel M, Haider FU. Effect of strigolactone on growth, photosynthetic efficiency, antioxidant activity, and osmolytes accumulation in different maize ( Zea mays L.) hybrids grown under drought stress. PLANT SIGNALING & BEHAVIOR 2023; 18:2262795. [PMID: 37767863 PMCID: PMC10730227 DOI: 10.1080/15592324.2023.2262795] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023]
Abstract
Drought alters plant physiology, morphology, and biochemical pathways, necessitating effective mitigation strategies. Strigolactones (SLs) are phytohormones known to enhance plant growth under abiotic stress. However, their specific impact on drought stress in maize remains unclear. This study aimed to determine the optimal SL concentration for mitigating drought stress in two maize hybrids (HY-1898, FH-1046). Maize plants were subjected to 60% field capacity drought stress in a pot experiment. After 40 d, different concentrations (0, 0.001, 0.01, and 0.1 mg L-1) of the synthetic SL analogue GR24 were applied to evaluate their effects on growth features, photosynthesis attributes, and osmolyte accumulation in the maize hybrids. Results showed that exogenous SL application significantly increased photosynthetic pigments in maize hybrids under drought stress. Chlorophyll content, gas exchange characteristics, net CO2 assimilation rate, stomatal conductance, water use efficiency, and antioxidant activities were enhanced by GR24. Leaf ascorbic acid and total phenolics also increased with SL application. Organic osmolytes, such as glycine betaine and free proline, were elevated in both maize hybrids under drought stress. Yield-related parameters, including cob diameter, cob weight, number of seeds per cob, and number of seeds per plant, were significantly increased by GR24 under drought stress. Our findings highlight the potential of GR24 foliar application to mitigate drought stress and promote maize growth and grain yield in a concentration-dependent manner. The minimum effective SL concentration against drought stress was determined to be 0.01 mg L-1. Overall, foliar application of GR24 could serve as a sustainable approach for drought tolerance in agriculture.
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Affiliation(s)
- Muhammad Luqman
- Department of Botany, University of Agriculture, Faisalabad, Pakistan
| | - Muhammad Shahbaz
- Department of Botany, University of Agriculture, Faisalabad, Pakistan
| | | | - Fozia Farhat
- Department of Botany, Government College Women University, Faisalabad, Pakistan
| | - Usman Zulfiqar
- Department of Agronomy, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Manzer H. Siddiqui
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Atifa Masood
- The department of Botany, University of Lahore, Sargodha, Pakistan
| | - Muhammad Aqeel
- State key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Fasih Ullah Haider
- Ecology, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Ecology, University of Chinese Academy of Sciences, Beijing, China
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Li Y, Li S, Feng Q, Zhang J, Han X, Zhang L, Yang F, Zhou J. Effects of exogenous Strigolactone on the physiological and ecological characteristics of Pennisetum purpureum Schum. Seedlings under drought stress. BMC PLANT BIOLOGY 2022; 22:578. [PMID: 36510126 PMCID: PMC9743734 DOI: 10.1186/s12870-022-03978-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/03/2022] [Indexed: 05/31/2023]
Abstract
BACKGROUND Drought is one of the main environmental factors limiting plant growth and development. Pennisetum purpureum Schum. was used to explore the mitigation effects of exogenous strigolactone (SL) on drought stress during the seedling stage. The effects of different concentrations (1, 3, 5, and 7 μmol·L- 1) of SL on the photosynthesis characteristics, growth performance, and endogenous abscisic acid (ABA) of P. purpureum under drought stress were studied. RESULTS Exogenous SL could effectively alleviate the inhibitory effect of drought stress on P. purpureum growth. Compared with drought stress, the net photosynthesis rate, stomatal conductance, transpiration rate, and water-use efficiency of the leaves of P. purpureum after SL treatment significantly increased, thereby exerting a significant mitigation effect on the decrease in photosystem II maximum photochemical efficiency and the performance index based on light absorption caused by drought. Moreover, the exogenous application of SL can effectively increase the fresh and dry weight of the leaves and roots and the main-root length. After applying SL for 120 h, the ABA content of P. purpureum decreased significantly. The activity of key enzymes of photosynthesis significantly increased after 48 h of external application of SL to P. purpureum. CONCLUSIONS SL treatment can improve the photosynthesis performance of P. purpureum leaves under drought conditions and increase the antioxidant capacity of the leaves, thereby reducing the adverse effects of drought, promoting the growth of P. purpureum, and effectively improving the drought resistance of P. purpureum.
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Affiliation(s)
- Yan Li
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- National Engineering Research Center of Juncao Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Sutao Li
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- National Engineering Research Center of Juncao Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Qixian Feng
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Juan Zhang
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xuelin Han
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lei Zhang
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Fulin Yang
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Jing Zhou
- National Engineering Research Center of Juncao Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Insights into removal of antibiotics by selected microalgae (Chlamydomonas reinhardtii, Chlorella sorokiniana, Dunaliella tertiolecta and Pseudokirchneriella subcapitata). ALGAL RES 2022. [DOI: 10.1016/j.algal.2021.102560] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mogany T, Bhola V, Ramanna L, Bux F. Photosynthesis and pigment production: elucidation of the interactive effects of nutrients and light on Chlamydomonas reinhardtii. Bioprocess Biosyst Eng 2021; 45:187-201. [PMID: 34668053 DOI: 10.1007/s00449-021-02651-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/30/2021] [Indexed: 01/22/2023]
Abstract
Chlamydomonas reinhardtii produces a variety of compounds that can be beneficial to human and animal health. Among these compounds, application of photosynthetic pigments, such as chlorophylls and carotenoids, has gained considerable interest in numerous industries. A better understanding on the interactive effects of essential nutrients and light on microalgal physiology and pigment production would be beneficial in improving cultivation strategies. Therefore, this study evaluated biomass, carotenoid and chlorophyll yield and the following fluorescence parameters: quantum yield in PS II [Y(II)] and electron transport rate (ETR) using response surface methodology (RSM). The Fv/Fm, Y(NO) and Y(NPQ) were also monitored; however, no significant relationship was observed. From the investigation it was apparent that nitrogen and carbon; as well as the interactive effects of (nitrogen and carbon) and (carbon and light irradiance) were significant factors. The model predicted the optimum conditions for maximum carotenoids (8.15 ± 0.389 mg g-1) were 08.7 mol l-1 of nitrogen, 0.2 mol l-1 and 50 μmol photon m-2 s-1 of light irradiance. While maximum chlorophyll (33.6 ± 0.854 mg g-1) required a higher nitrogen (11.21 mol l-1). The photosynthetic parameters [Y(II), ETR] was correlated with the primary pigments and biomass production. Increased photosynthetic activity was associated with high carbon and light. The Y(II)and ETR of PSII under these conditions were 0.2 and ~ 14, respectively. This approach was accurate in developing the model, optimizing factors and analysing interaction effects. This study served to provide a better understanding on the interactions between factors influencing pigment biosynthesis and photosynthetic performance of Chlamydomonas reinhardtii.
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Affiliation(s)
- Trisha Mogany
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Virthie Bhola
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Luveshan Ramanna
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa.
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Mariam I, Kareya MS, Nesamma AA, Jutur PP. Delineating metabolomic changes in native isolate Aurantiochytrium for production of docosahexaenoic acid in presence of varying carbon substrates. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102285] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Stirbet A, Lazár D, Guo Y, Govindjee G. Photosynthesis: basics, history and modelling. ANNALS OF BOTANY 2020; 126:511-537. [PMID: 31641747 PMCID: PMC7489092 DOI: 10.1093/aob/mcz171] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/06/2019] [Accepted: 10/21/2019] [Indexed: 05/02/2023]
Abstract
BACKGROUND With limited agricultural land and increasing human population, it is essential to enhance overall photosynthesis and thus productivity. Oxygenic photosynthesis begins with light absorption, followed by excitation energy transfer to the reaction centres, primary photochemistry, electron and proton transport, NADPH and ATP synthesis, and then CO2 fixation (Calvin-Benson cycle, as well as Hatch-Slack cycle). Here we cover some of the discoveries related to this process, such as the existence of two light reactions and two photosystems connected by an electron transport 'chain' (the Z-scheme), chemiosmotic hypothesis for ATP synthesis, water oxidation clock for oxygen evolution, steps for carbon fixation, and finally the diverse mechanisms of regulatory processes, such as 'state transitions' and 'non-photochemical quenching' of the excited state of chlorophyll a. SCOPE In this review, we emphasize that mathematical modelling is a highly valuable tool in understanding and making predictions regarding photosynthesis. Different mathematical models have been used to examine current theories on diverse photosynthetic processes; these have been validated through simulation(s) of available experimental data, such as chlorophyll a fluorescence induction, measured with fluorometers using continuous (or modulated) exciting light, and absorbance changes at 820 nm (ΔA820) related to redox changes in P700, the reaction centre of photosystem I. CONCLUSIONS We highlight here the important role of modelling in deciphering and untangling complex photosynthesis processes taking place simultaneously, as well as in predicting possible ways to obtain higher biomass and productivity in plants, algae and cyanobacteria.
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Affiliation(s)
| | - Dušan Lazár
- Department of Biophysics, Center of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Jiangnan University, Wuxi, China
- University of Missouri, Columbia, MO, USA
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Tuttle JT, Williams JR, Higgs DC. Characterization of a Chlamydomonas reinhardtii mutant strain with tolerance to low nitrogen and increased growth and biomass under nitrogen stress. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Kareya MS, Mariam I, Shaikh KM, Nesamma AA, Jutur PP. Photosynthetic Carbon Partitioning and Metabolic Regulation in Response to Very-Low and High CO 2 in Microchloropsis gaditana NIES 2587. FRONTIERS IN PLANT SCIENCE 2020; 11:981. [PMID: 32719702 PMCID: PMC7348049 DOI: 10.3389/fpls.2020.00981] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 06/16/2020] [Indexed: 05/06/2023]
Abstract
Photosynthetic organisms fix inorganic carbon through carbon capture machinery (CCM) that regulates the assimilation and accumulation of carbon around ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, few constraints that govern the central carbon metabolism are regulated by the carbon capture and partitioning machinery. In order to divert the cellular metabolism toward lipids and/or biorenewables it is important to investigate and understand the molecular mechanisms of the CO2-driven carbon partitioning. In this context, strategies for enhancement of CO2 fixation which will increase the overall biomass and lipid yields, can provide clues on understanding the carbon assimilation pathway, and may lead to new targets for genetic engineering in microalgae. In the present study, we have focused on the physiological and metabolomic response occurring within marine oleaginous microalgae Microchloropsis gaditana NIES 2587, under the influence of very-low CO2 (VLC; 300 ppm, or 0.03%) and high CO2 (HC; 30,000 ppm, or 3% v/v). Our results demonstrate that HC supplementation in M. gaditana channelizes the carbon flux toward the production of long chain polyunsaturated fatty acids (LC-PUFAs) and also increases the overall biomass productivities (up to 2.0 fold). Also, the qualitative metabolomics has identified nearly 31 essential metabolites, among which there is a significant fold change observed in accumulation of sugars and alcohols such as galactose and phytol in VLC as compared to HC. In conclusion, our focus is to understand the entire carbon partitioning and metabolic regulation within these photosynthetic cell factories, which will be further evaluated through multiomics approach for enhanced productivities of biomass, biofuels, and bioproducts (B3).
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Affiliation(s)
| | | | | | | | - Pannaga Pavan Jutur
- Omics of Algae Group, Industrial Biotechnology, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Slocombe SP, Zúñiga-Burgos T, Chu L, Wood NJ, Camargo-Valero MA, Baker A. Fixing the Broken Phosphorus Cycle: Wastewater Remediation by Microalgal Polyphosphates. FRONTIERS IN PLANT SCIENCE 2020; 11:982. [PMID: 32695134 PMCID: PMC7339613 DOI: 10.3389/fpls.2020.00982] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/16/2020] [Indexed: 05/06/2023]
Abstract
Phosphorus (P), in the form of phosphate derived from either inorganic (Pi) or organic (Po) forms is an essential macronutrient for all life. P undergoes a biogeochemical cycle within the environment, but anthropogenic redistribution through inefficient agricultural practice and inadequate nutrient recovery at wastewater treatment works have resulted in a sustained transfer of P from rock deposits to land and aquatic environments. Our present and near future supply of P is primarily mined from rock P reserves in a limited number of geographical regions. To help ensure that this resource is adequate for humanity's food security, an energy-efficient means of recovering P from waste and recycling it for agriculture is required. This will also help to address excess discharge to water bodies and the resulting eutrophication. Microalgae possess the advantage of polymeric inorganic polyphosphate (PolyP) storage which can potentially operate simultaneously with remediation of waste nitrogen and phosphorus streams and flue gases (CO2, SOx, and NOx). Having high productivity in photoautotrophic, mixotrophic or heterotrophic growth modes, they can be harnessed in wastewater remediation strategies for biofuel production either directly (biodiesel) or in conjunction with anaerobic digestion (biogas) or dark fermentation (biohydrogen). Regulation of algal P uptake, storage, and mobilization is intertwined with the cellular status of other macronutrients (e.g., nitrogen and sulphur) in addition to the manufacture of other storage products (e.g., carbohydrate and lipids) or macromolecules (e.g., cell wall). A greater understanding of controlling factors in this complex interaction is required to facilitate and improve P control, recovery, and reuse from waste streams. The best understood algal genetic model is Chlamydomonas reinhardtii in terms of utility and shared resources. It also displays mixotrophic growth and advantageously, species of this genus are often found growing in wastewater treatment plants. In this review, we focus primarily on the molecular and genetic aspects of PolyP production or turnover and place this knowledge in the context of wastewater remediation and highlight developments and challenges in this field.
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Affiliation(s)
- Stephen P. Slocombe
- Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Tatiana Zúñiga-Burgos
- Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
- BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom
| | - Lili Chu
- Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Nicola J. Wood
- Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
- Centre for Doctoral Training in Bioenergy, School of Chemical and Process Engineering, University of Leeds, Leeds, United Kingdom
| | - Miller Alonso Camargo-Valero
- BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom
- Departamento de Ingeniería Química, Universidad Nacional de Colombia, Manizales, Colombia
| | - Alison Baker
- Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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Agarwal A, Shaikh KM, Gharat K, Jutur PP, Pandit RA, Lali AM. Investigating the modulation of metabolites under high light in mixotrophic alga Asteracys sp. using a metabolomic approach. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Lu T, Yu H, Li Q, Chai L, Jiang W. Improving Plant Growth and Alleviating Photosynthetic Inhibition and Oxidative Stress From Low-Light Stress With Exogenous GR24 in Tomato ( Solanum lycopersicum L.) Seedlings. FRONTIERS IN PLANT SCIENCE 2019; 10:490. [PMID: 31057589 PMCID: PMC6477451 DOI: 10.3389/fpls.2019.00490] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 04/01/2019] [Indexed: 05/20/2023]
Abstract
Low light (LL) is one of the main limiting factors that negatively affect tomato growth and yield. Techniques of chemical regulation are effective horticultural methods to improve stress resistance. Strigolactones (SLs), newly discovered phytohormones, are considered as important regulators of physiological responses. We investigated the effects of foliage spray of GR24, a synthesized SLs, on tomato seedlings grown under LL stress conditions. The results showed that application of GR24 effectively mitigated the inhibition of plant growth and increased the fresh and dry weight of tomato plants under LL. Additionally, GR24 also increased the chlorophyll content (Chla and Chlb), the net photosynthetic rate (Pn), the photochemical efficiency of photosystem (PS) II (Fv/Fm), and the effective quantum yield of PSII and I [Y(II) and Y(I)], but decreased the excitation pressure of PSII (1-qP), the non-regulatory quantum yield of energy dissipation [Y(NO)] and the donor side limitation of PSI [Y(ND)] under LL. Moreover, application of GR24 to LL-stressed tomato leaves increased the electron transport rate of PSII and PSI [ETR(II) and ETR(I)], the ratio of the quantum yield of cyclic electron flow (CEF) to Y(II) [Y(CEF)/Y(II)], the oxidized plastoquinone (PQ) pool size and the non-photochemical quenching. Besides, GR24 application increased the activity and gene expression of antioxidant enzymes, but it reduced malonaldehyde (MDA) and hydrogen peroxide (H2O2) content in LL-stressed plants. These results suggest that exogenous application of GR24 enhances plant tolerance to LL by promoting plant utilization of light energy to alleviate the photosystem injuries induced by excess light energy and ROS, and enhancing photosynthesis efficiency to improve plant growth.
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Affiliation(s)
| | | | | | | | - Weijie Jiang
- Key Laboratory of Horticultural Crops Genetic Improvement (Ministry of Agriculture), Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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Agarwal A, Patil S, Gharat K, Pandit RA, Lali AM. Modulation in light utilization by a microalga Asteracys sp. under mixotrophic growth regimes. PHOTOSYNTHESIS RESEARCH 2019; 139:553-567. [PMID: 29860703 DOI: 10.1007/s11120-018-0526-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/28/2018] [Indexed: 05/22/2023]
Abstract
This study is the first to explore the influence of incident light intensity on the photosynthetic responses under mixotrophic growth of microalga Asteracys sp. When grown mixotrophically, there was an enhanced regulation of non-photochemical quenching (NPQ) of the excited state of chlorophyll (Chl) a within the cells in response to white cool fluorescent high light (HL; 600 µmol photons m-2 s-1). Simultaneous measurement of reactive oxygen species (ROS) production as malondialdehyde (MDA) and ascorbate peroxidase (APX), an ROS scavenger, showed improved management of stress within mixotrophic cells under HL. Despite the observed decrease in quantum yield of photosynthesis measured through the Chl a fluorescence transient, no reduction in biomass accumulation was observed under HL for mixotrophy. However, biomass loss owing to photoinhibition was observed in cells grown phototrophically under the same irradiance. The measurements of dark recovery of NPQ suggested that "state transitions" may be partly responsible for regulating overall photosynthesis in Asteracys sp. The partitioning of photochemical and non-photochemical processes to sustain HL stress was analysed. Collectively, this study proposes that mixotrophy using glucose leads to a change in the photosynthetic abilities of Asteracys sp. while enhancing the adaptability of the alga to high irradiances.
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Affiliation(s)
- Akanksha Agarwal
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India
| | - Smita Patil
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India
| | - Krushna Gharat
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India
| | - Reena A Pandit
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India.
| | - Arvind M Lali
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India
- Department of Chemical Engineering, Institute of Chemical Technology, Mumbai, Maharashtra, 400019, India
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13
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Stirbet A. The slow phase of chlorophyll a fluorescence induction in silico: Origin of the S-M fluorescence rise. PHOTOSYNTHESIS RESEARCH 2016; 130:193-213. [PMID: 26995191 DOI: 10.1007/s11120-016-0243-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/04/2016] [Indexed: 06/05/2023]
Abstract
In higher plants, algae, and cyanobacteria, chlorophyll (Chl) a fluorescence induction (ChlFI) has a fast (under a second) increasing OJIP phase and a slow (few minutes) PS(M)T phase, where O is for origin, the minimum fluorescence, J and I for intermediate levels, P for peak, S for a semi-steady state, M for a maximum (which is sometimes missing), and T for the terminal steady-state level. We have used a photosynthesis model of Ebenhöh et al. (Philos Trans R Soc B, 2014, doi: 10.1098/rstb.2013.0223 ) in an attempt to simulate the slow PS(M)T phase and to determine the origin of the S-M rise in Chlamydomonas (C.) reinhardtii cells. Our experiments in silico show that a slow fluorescence S-M rise (as that observed, e.g., by Kodru et al. (Photosynth Res 125:219-231, 2015) can be simulated only if the photosynthetic samples are initially in a so-called "state 2," when the absorption cross section (CS) of Photosystem II (PSII) is lower than that of PSI, and Chl a fluorescence is low (see, e.g., a review by Papageorgiou and Govindjee (J Photochem Photobiol B 104:258-270, 2011). In this case, simulations show that illumination induces a state 2 (s2) to state 1 (s1) transition (qT21), and a slow S-M rise in the simulated ChlFI curve, since the fluorescence yield is known to be higher in s1, when CS of PSII is larger than that of PSI. Additionally, we have analyzed how light intensity and several photosynthetic processes influence the degree of this qT21, and thus the relative amplitude of the simulated S-M phase. A refinement of the photosynthesis model is, however, necessary in order to obtain a better fit of the simulation data with the measured ChlFI curves.
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Banerjee C, Dubey KK, Shukla P. Metabolic Engineering of Microalgal Based Biofuel Production: Prospects and Challenges. Front Microbiol 2016; 7:432. [PMID: 27065986 PMCID: PMC4815533 DOI: 10.3389/fmicb.2016.00432] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/17/2016] [Indexed: 12/14/2022] Open
Abstract
The current scenario in renewable energy is focused on development of alternate and sustainable energy sources, amongst which microalgae stands as one of the promising feedstock for biofuel production. It is well known that microalgae generate much larger amounts of biofuels in a shorter time than other sources based on plant seeds. However, the greatest challenge in a transition to algae-based biofuel production is the various other complications involved in microalgal cultivation, its harvesting, concentration, drying and lipid extraction. Several green microalgae accumulate lipids, especially triacylglycerols (TAGs), which are main precursors in the production of lipid. The various aspects on metabolic pathway analysis of an oleaginous microalgae i.e., Chlamydomonas reinhardtii have elucidated some novel metabolically important genes and this enhances the lipid production in this microalgae. Adding to it, various other aspects in metabolic engineering using OptFlux and effectual bioprocess design also gives an interactive snapshot of enhancing lipid production which ultimately improvises the oil yield. This article reviews the current status of microalgal based technologies for biofuel production, bioreactor process design, flux analysis and it also provides various strategies to increase lipids accumulation via metabolic engineering.
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Affiliation(s)
- Chiranjib Banerjee
- Department of Environmental Science and Engineering, Indian School of Mines Dhanbad, India
| | - Kashyap K Dubey
- Department of Biotechnology, University Institute of Engineering and Technology, Maharshi Dayanand University Rohtak, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University Rohtak, India
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15
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Zalutskaya Z, Lapina T, Ermilova E. The Chlamydomonas reinhardtii alternative oxidase 1 is regulated by heat stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 97:229-34. [PMID: 26492131 DOI: 10.1016/j.plaphy.2015.10.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/03/2015] [Accepted: 10/09/2015] [Indexed: 05/27/2023]
Abstract
The alternative oxidase (AOX) is a non-energy conserving terminal oxidase that has emerged as an important mitochondrial component of the cell stress responses. Although the most studied abiotic condition in relation to Chlamydomonas reinhardtii is high temperature, changes in AOX capacity of the alga were studied only under oxidative stress and cold. To examine whether elevated temperatures affected AOX1 expression, we applied quantitative real-time PCR and pharmaceutical approaches. In this work, we demonstrated a sharp increase in AOX1 transcript and protein abundance under heat stress. Furthermore, C. reinhardtii cells displayed a large increase in alternative respiration in response to high temperature. Feeding with the protein kinase inhibitor staurosporine strongly retarded the AOX1 transcription. Finally, the addition of the calcium chelator EGTA prevented heat-induced AOX1 expression. Together, our results imply that heat-inducible Ca(2+) influx and protein kinase(s) may mediate AOX1 expression at elevated temperatures. Characterization of heat-induced AOX1 regulation in the green alga C. reinhardtii provides a framework for a more complete understanding of the function of this conserved protein.
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Affiliation(s)
- Zhanneta Zalutskaya
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Tatiana Lapina
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Elena Ermilova
- Lab Adaptation in Microorganisms, Biological Faculty, Saint-Petersburg State University, Saint-Petersburg, Russia.
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