1
|
Ben Abdallah M, Chamkha M, Karray F, Sayadi S. Microbial diversity in polyextreme salt flats and their potential applications. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:11371-11405. [PMID: 38180652 DOI: 10.1007/s11356-023-31644-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 12/17/2023] [Indexed: 01/06/2024]
Abstract
Recent geological, hydrochemical, and mineralogical studies performed on hypersaline salt flats have given insights into similar geo-morphologic features on Mars. These salt-encrusted depressions are widely spread across the Earth, where they are characterized by high salt concentrations, intense UV radiation, high evaporation, and low precipitation. Their surfaces are completely dry in summer; intermittent flooding occurs in winter turning them into transitory hypersaline lakes. Thanks to new approaches such as culture-dependent, culture-independent, and metagenomic-based methods, it is important to study microbial life under polyextreme conditions and understand what lives in these dynamic ecosystems and how they function. Regarding these particular features, new halophilic microorganisms have been isolated from some salt flats and identified as excellent producers of primary and secondary metabolites and granules such as halocins, enzymes, carotenoids, polyhydroxyalkanoates, and exopolysaccharides. Additionally, halophilic microorganisms are implemented in heavy metal bioremediation and hypersaline wastewater treatment. As a result, there is a growing interest in the distribution of halophilic microorganisms around the world that can be looked upon as good models to develop sustainable biotechnological processes for all fields. This review provides insights into diversity, ecology, metabolism, and genomics of halophiles in hypersaline salt flats worldwide as well as their potential uses in biotechnology.
Collapse
Affiliation(s)
- Manel Ben Abdallah
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia.
| | - Mohamed Chamkha
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Fatma Karray
- Laboratory of Environmental Bioprocesses, Centre of Biotechnology of Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Sami Sayadi
- Biotechnology Program, Center for Sustainable Development, College of Arts and Sciences, Qatar University, 2713, Doha, Qatar
| |
Collapse
|
2
|
Mohanta A, Prasad N, Khadim SR, Singh P, Singh S, Singh A, Kayastha AM, Asthana RK. Optimizing light regimes for neutral lipid accumulation in Dunaliella salina MCC 43: a study on physiological status and carbon allocation. World J Microbiol Biotechnol 2024; 40:82. [PMID: 38285311 DOI: 10.1007/s11274-024-03893-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/10/2024] [Indexed: 01/30/2024]
Abstract
Dunaliella salina is a favourable source of high lipid feedstock for biofuel and medicinal chemicals. Low biomass output from microalgae is a significant barrier to industrial-scale commercialisation. The current study aimed to determine how photosynthetic efficiency, carbon fixation, macromolecular synthesis, accumulation of neutral lipids, and antioxidative defence (ROS scavenging enzyme activities) of D. salina cells were affected by different light intensities (LI) (50, 100, 200, and 400 µmol m-2 s-1). The cells when exposed to strong light (400 µmol m-2 s-1) led to reduction in chlorophyll a but the carotenoid content increased by 19% in comparison to the control (LI 100). The amount of carbohydrate changed significantly under high light and in spite of stress inflicted on the cells by high irradiation, a considerable increase in activity of carbonic anhydrase and fixation rate of CO2 were recorded, thus, preserving the biomass content. The high light exposed biomass when subjected to nitrogen-deficient medium led to increase in lipid content (59.92% of the dry cell weight). However, neutral lipid made up 78.26% of the total lipid while other lipids like phospholipid and glycolipid content decreased, showing that the lipid was redistributed in these cells under nitrogen deprivation, making the organism more appropriate for biodiesel/jet fuel use. Although D. salina cells had a relatively longer generation time (3.5 d) than other microalgal cells, an economic analysis concluded that the amount of carotenoid they produced and the quality of their lipids made them more suited for commercialization.
Collapse
Affiliation(s)
- Abhishek Mohanta
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Nitesh Prasad
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Sk Riyazat Khadim
- P.G. Department of Botany, Dhenkanal Autonomous College, Dhenkanal, Odisha, India
| | - Prabhakar Singh
- Biochemistry Department, North-Eastern Hill University, Shillong, Meghalaya, 793022, India
| | - Savita Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Avinash Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
| | - A M Kayastha
- School of Biotechnology, Banaras Hindu University, Varanasi, 221005, India
| | - R K Asthana
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India.
| |
Collapse
|
3
|
Singh U, Singh P, Singh AK, Singh S, Kumar D, Shrivastava SK, Asthana RK. In silico and in vitro evaluation of extract derived from Dunaliella salina, a halotolerant microalga for its antifungal and antibacterial activity. J Biomol Struct Dyn 2023; 41:7069-7083. [PMID: 36017823 DOI: 10.1080/07391102.2022.2115556] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 08/14/2022] [Indexed: 10/15/2022]
Abstract
In the present study little explored halotolerant wall-less green alga Dunaliella salina was found to be a potent source of antibacterial and antifungal biomolecules. Both the target pathogens, bacteria (Escherischia coli, Klebsiella pneumoniae, and Acinetobacter baumannii) and fungi (Candida albicans, C. tropicalis, and Cryptococus sp.) were WHO prioritized. The bioassay guided approach led us to evaluate antibacterial and antifungal lead molecule(s) from an array of compounds using spectroscopic and in silico studies. The methanol derived crude extract was purified via thin layer chromatography (TLC) using solvent system methanol: chloroform (1:19). Maximum antimicrobial activity was observed in fractions D5, D6 and D7, the components of which were then recognized using high resolution-liquid chromatography/mass spectroscopy (Orbitrap) (HR-LC/MS). The screened compounds were then docked with target enzymes sterol-14-alpha demethylase and OmpF porin protein. The energy scores revealed that amongst all, lariciresinol-4-O-glucoside showed better binding affinity, in silico, using the Schrödinger Maestro 2018-1 platform. The 3-dimensional crystal structures of both the proteins were retrieved from the protein data bank (PDB), and showed binding energies of -14.35 kcal/mol, and -11.0 kcal/mol against respective drug targets. The molecular dynamics (MD) simulations were performed for 100 ns, using Desmond package, Schrödinger to evaluate the conformational stability and alteration of protein-ligand complexes during the simulation. Thus, our findings confirmed that lariciresinol-4-O-glucoside, a lignan derivative and known strong antioxidant, may be used as an important "lead" molecule to be developed as antibacterial and antifungal drugs in the future.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Urmilesh Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Prabhakar Singh
- Biochemistry Department, North Eastern Hill University, Shillong, Meghalaya, India
| | - Ankit Kumar Singh
- Department of Botany, Marwari College (a constituent unit of Lalit Narayan Mithila University), Darbhanga, Bihar, India
| | - Sweksha Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Deepak Kumar
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Sushant Kumar Shrivastava
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ravi Kumar Asthana
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| |
Collapse
|
4
|
Singh RP, Yadav P, Kumar A, Hashem A, Avila-Quezada GD, Abd_Allah EF, Gupta RK. Salinity-Induced Physiochemical Alterations to Enhance Lipid Content in Oleaginous Microalgae Scenedesmus sp. BHU1 via Two-Stage Cultivation for Biodiesel Feedstock. Microorganisms 2023; 11:2064. [PMID: 37630624 PMCID: PMC10459255 DOI: 10.3390/microorganisms11082064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock.
Collapse
Affiliation(s)
- Rahul Prasad Singh
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (R.P.S.); (P.Y.)
| | - Priya Yadav
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (R.P.S.); (P.Y.)
| | - Ajay Kumar
- Amity Institute of Biotechnology, Amity University, Noida 201303, India
| | - Abeer Hashem
- Botany and Microbiology Department, College of Science, King Saud University, P.O. Box. 2460, Riyadh 11451, Saudi Arabia;
| | | | - Elsayed Fathi Abd_Allah
- Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box. 2460, Riyadh 11451, Saudi Arabia;
| | - Rajan Kumar Gupta
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India; (R.P.S.); (P.Y.)
| |
Collapse
|
5
|
Singh P, Singh S, Maurya P, Mohanta A, Dubey H, Khadim SR, Singh AK, Pandey AK, Singh AK, Asthana RK. Bioaccumulation of selenium in halotolerant microalga Dunaliella salina and its impact on photosynthesis, reactive oxygen species, antioxidative enzymes, and neutral lipids. MARINE POLLUTION BULLETIN 2023; 190:114842. [PMID: 36965269 DOI: 10.1016/j.marpolbul.2023.114842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Selenium (Se) is an essential element for living systems, however, toxic at higher levels. In the present study, Dunaliella salina cells were exposed to different Se concentrations for their growth (EC50 195 mg L-1) as well as Se accumulation. The cells exposed to 50 mg L-1 Se showed photoautotrophic growth parallel to control and accumulated 65 μg Se g-1 DW. A decrease in photosynthetic quantum yield, chlorophyll content, and the increase in intracellular reactive oxygen species, proline content, and lipid peroxidation accompanied by higher neutral lipid accumulation, were recorded at higher Se level. The enzymes superoxide dismutase and catalase played a pivotal role in antioxidative defense. Heterogeneity in accumulated carotenoids at varying concentrations of selenium was prevalent. The cells exposed to 200 mg L-1 Se resulted in the disorganization of organelles. Thus, the Se enriched biomass obtained at 50 mg L-1 may be explored for bio-fortification of food and feed.
Collapse
Affiliation(s)
- Prabhakar Singh
- Biochemistry Department, North Eastern Hill University, Shillong 793022, India
| | - Sakshi Singh
- Interdisciplinary School of Life Sciences, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Priyanka Maurya
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India
| | - Abhishek Mohanta
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India
| | - Hardik Dubey
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India
| | - Sk Riyazat Khadim
- Department of Botany, Model Degree College, Nabarangpur, Odisha 764063, India
| | - Ankit K Singh
- Department of Botany, Marwari College (a Constituent Unit of Lalit Narayan Mithila University), Darbhanga 846004, India
| | - Adarsh K Pandey
- Sophisticated Analytical and Technical Help Institute (SATHI), Banaras Hindu University, Varanasi 221005, India
| | - Arvind K Singh
- Biochemistry Department, North Eastern Hill University, Shillong 793022, India
| | - Ravi K Asthana
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India.
| |
Collapse
|
6
|
Singh RP, Yadav P, Kumar A, Hashem A, Al-Arjani ABF, Abd Allah EF, Rodríguez Dorantes A, Gupta RK. Physiological and Biochemical Responses of Bicarbonate Supplementation on Biomass and Lipid Content of Green Algae Scenedesmus sp. BHU1 Isolated From Wastewater for Renewable Biofuel Feedstock. Front Microbiol 2022; 13:839800. [PMID: 35444634 PMCID: PMC9015788 DOI: 10.3389/fmicb.2022.839800] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/15/2022] [Indexed: 11/15/2022] Open
Abstract
In the present study, different microalgae were isolated from wastewater environment and evaluated for higher growth and lipid accumulation. The growth adaptability of all the isolated microalgae were tested for carbon source with supplementation of sodium bicarbonate in BG-11 N+ medium. Further based on the uptake rate of sodium bicarbonate and growth behavior, microalgal strains were selected for biofuel feedstock. During the study, growth parameters of all the isolates were screened after supplementation with various carbon sources, in which strain Scenedesmus sp. BHU1 was found highly effective among all. The efficacy of Scenedesmus sp. BHU1 strain under different sodium bicarbonate (4–20 mM) concentration, in which higher growth 1.4 times greater than control was observed at the concentration 12 mM sodium bicarbonate. In addition, total chlorophyll content (Chl-a + Chl-b), chlorophyll fluorescence (Fv/Fm, Y(II), ETR max, and NPQmax), and biomass productivity were found to be 11.514 μg/ml, 0.673, 0.675, and 31.167 μmol electrons m−2 s−1, 1.399, 59.167 mg/L/day, respectively, at the 12 mM sodium bicarbonate. However, under optimum sodium bicarbonate supplementation, 56.920% carbohydrate and 34.693% lipid content were accumulated, which showed potential of sodium bicarbonate supplementation in renewable biofuel feedstock by using Scenedesmus sp. BHU1 strain.
Collapse
Affiliation(s)
- Rahul Prasad Singh
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Priya Yadav
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Ajay Kumar
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Abeer Hashem
- Botany and Microbiology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | | | - Elsayed Fathi Abd Allah
- Plant Production Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
| | | | - Rajan Kumar Gupta
- Laboratory of Algal Research, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| |
Collapse
|
7
|
Wan Afifudeen CL, Teh KY, Cha TS. Bioprospecting of microalgae metabolites against cytokine storm syndrome during COVID-19. Mol Biol Rep 2022; 49:1475-1490. [PMID: 34751914 PMCID: PMC8576090 DOI: 10.1007/s11033-021-06903-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 10/29/2021] [Indexed: 01/18/2023]
Abstract
In viral respiratory infections, disrupted pathophysiological outcomes have been attributed to hyper-activated and unresolved inflammation responses of the immune system. Integration between available drugs and natural therapeutics have reported benefits in relieving inflammation-related physiological outcomes and microalgae may be a feasible source from which to draw from against future coronavirus-infections. Microalgae represent a large and diverse source of chemically functional compounds such as carotenoids and lipids that possess various bioactivities, including anti-inflammatory properties. Therefore in this paper, some implicated pathways causing inflammation in viral respiratory infections are discussed and juxtaposed along with available research done on several microalgal metabolites. Additionally, the therapeutic properties of some known anti-inflammatory, antioxidant and immunomodulating compounds sourced from microalgae are reported for added clarity.
Collapse
Affiliation(s)
- Che Lah Wan Afifudeen
- Satreps-Cosmos Laboratory, Central Laboratory Complex, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
- Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
| | - Kit Yinn Teh
- Satreps-Cosmos Laboratory, Central Laboratory Complex, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
- Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
| | - Thye San Cha
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
- Satreps-Cosmos Laboratory, Central Laboratory Complex, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu Malaysia
| |
Collapse
|
8
|
CRISPR/Cas technology promotes the various application of Dunaliella salina system. Appl Microbiol Biotechnol 2020; 104:8621-8630. [PMID: 32918585 DOI: 10.1007/s00253-020-10892-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/01/2020] [Accepted: 09/05/2020] [Indexed: 12/15/2022]
Abstract
Dunaliella salina (D. salina) has been widely applied in various fields because of its inherent advantages, such as the study of halotolerant mechanism, wastewater treatment, recombinant proteins expression, biofuel production, preparation of natural materials, and others. However, owing to the existence of low yield or in the laboratory exploration stage, D. salina system has been greatly restricted for practical production of various components. In past decade, significant progresses have been achieved for research of D. salina in these fields. Among them, D. salina as a novel expression system demonstrated a bright prospect, especially for large-scale production of foreign proteins, like the vaccines, antibodies, and other therapeutic proteins. Due to the low efficiency, application of traditional regulation tools is also greatly limited for exploration of D. salina system. The emergence of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system offers a precise editing tool to overcome the obstacles of D. salina system. This review not only comprehensively summarizes the recent progresses of D. salina in domain of gene engineering but also gives a deep analysis of problems and deficiencies in different fields of D. salina. Moreover, further prospects of CRISPR/Cas system and its significant challenges have been discussed in various aspects of D. salina. It provides a great referencing value for speeding up the maturity of D. salina system, and also supplies practical guiding significance to expand the new application fields for D. salina. KEY POINTS: • The review provides recent research progresses of various applications of D. salina. • The problems and deficiencies in different fields of D. salina were deeply analyzed. • The further prospects of CRISPR/Cas technology in D. salina system were predicted. • CRISPR/Cas system will promote the new application fields and maturity for D. salina.
Collapse
|
9
|
Tang Z, Cao X, Zhang Y, Jiang J, Qiao D, Xu H, Cao Y. Two splice variants of the DsMEK1 mitogen-activated protein kinase kinase (MAPKK) are involved in salt stress regulation in Dunaliella salina in different ways. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:147. [PMID: 32843896 PMCID: PMC7439689 DOI: 10.1186/s13068-020-01786-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/24/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND Dunaliella salina can produce glycerol under salt stress, and this production can quickly adapt to changes in external salt concentration. Notably, glycerol is an ideal energy source. In recent years, it has been reported that the mitogen-activated protein kinase cascade pathway plays an important role in regulating salt stress, and in Dunaliella tertiolecta DtMAPK can regulate glycerol synthesis under salt stress. Therefore, it is highly important to study the relationship between the MAPK cascade pathway and salt stress in D. salina and modify it to increase the production of glycerol. RESULTS In our study, we identified and analysed the alternative splicing of DsMEK1 (DsMEK1-X1, DsMEK1-X2) from the unicellular green alga D. salina. DsMEK1-X1 and DsMEK1-X2 were both localized in the cytoplasm. qRT-PCR assays showed that DsMEK1-X2 was induced by salt stress. Overexpression of DsMEK1-X2 revealed a higher increase rate of glycerol production compared to the control and DsMEK1-X1-oe under salt stress. Under salt stress, the expression of DsGPDH2/3/5/6 increased in DsMEK1-X2-oe strains compared to the control. This finding indicated that DsMEK1-X2 was involved in the regulation of DsGPDH expression and glycerol overexpression under salt stress. Overexpression of DsMEK1-X1 increased the proline content and reduced the MDA content under salt stress, and DsMEK1-X1 was able to regulate oxidative stress; thus, we hypothesized that DsMEK1-X1 could reduce oxidative damage under salt stress. Yeast two-hybrid analysis showed that DsMEK1-X2 could interact with DsMAPKKK1/2/3/9/10/17 and DsMAPK1; however, DsMEK1-X1 interacted with neither upstream MAPKKK nor downstream MAPK. DsMEK1-X2-oe transgenic lines increased the expression of DsMAPKKK1/3/10/17 and DsMAPK1, and DsMEK1-X2-RNAi lines decreased the expression of DsMAPKKK2/10/17. DsMEK1-X1-oe transgenic lines did not exhibit increased gene expression, except for DsMAPKKK9. CONCLUSION Our findings demonstrate that DsMEK1-X1 and DsMEK1-X2 can respond to salt stress by two different pathways. The DsMEK1-X1 response to salt stress reduces oxidative damage; however, the DsMAPKKK1/2/3/9/10/17-DsMEK1-X2-DsMAPK1 cascade is involved in the regulation of DsGPDH expression and thus glycerol synthesis under salt stress.
Collapse
Affiliation(s)
- Ziyi Tang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Xiyue Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Yiping Zhang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Jia Jiang
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Dairong Qiao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Hui Xu
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| | - Yi Cao
- Microbiology and Metabolic Engineering Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065 China
| |
Collapse
|
10
|
Singh AK, Tiwari R, Singh VK, Singh P, Khadim SR, Singh U, Laxmi, Srivastava V, Hasan S, Asthana R. Green synthesis of gold nanoparticles from Dunaliella salina, its characterization and in vitro anticancer activity on breast cancer cell line. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.02.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|