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Abu-Ghosh S, Iluz D, Dubinsky Z, Miller G. Exogenous Abscisic Acid Confers Salinity Tolerance in Chlamydomonas reinhardtii During Its Life Cycle. JOURNAL OF PHYCOLOGY 2021; 57:1323-1334. [PMID: 33963561 DOI: 10.1111/jpy.13174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
The plant hormone abscisic acid (ABA) coordinates responses to environmental signals with developmental changes and is important for stress resilience and crop yield. However, fundamental questions remain about how this phytohormone affects microalgal growth and stress regulation throughout the different stages of their life cycle. In this study, the effects of ABA on the physiology of the freshwater microalga Chlamydomonas reinhardtii at its different life cycle stages were investigated. Exogenously added ABA enhanced the growth and photosynthesis of C. reinhardtii during the vegetative stage. The hormone also increased the tolerance of this alga to high-salinity stress during gamete formation under nutrient depletion, as well as it extended their survival. We show that the level of reactive oxygen species (ROS) generated in the ABA-treated cells was significantly less than that in the untreated cells under inhibiting NaCl concentrations. Cell size examination showed that ABA prevents cells from forming palmella when exposed to high salinity. All together, these results suggest that ABA can support the vitality and survival of C. reinhardtii under high salt conditions.
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Affiliation(s)
- Said Abu-Ghosh
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
- Bar Ilan Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - David Iluz
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
- Environmental Sciences and Agriculture, Beit Berl Academic College, Kfar Saba, Israel
- Deptartment of science, Talpiot Academic College, Holon, Israel
| | - Zvy Dubinsky
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
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Zheng C, Aslam M, Liu X, Du H, Xie X, Jia H, Huang N, Tang K, Yang Y, Li P. Impact of Pb on Chlamydomonas reinhardtii at Physiological and Transcriptional Levels. Front Microbiol 2020; 11:1443. [PMID: 32676066 PMCID: PMC7333365 DOI: 10.3389/fmicb.2020.01443] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Trace elements stress is one of the most damaging abiotic stresses in environment. Nevertheless, the defense mechanism in microalgae remains poorly understood. In this study, physiological and molecular methods were performed to analyze the defense responses in green alga Chlamydomonas reinhardtii. It was speculated that the defense responses might mainly be due to the regulation of hormone signaling, indicating its potential role in alleviating the Pb toxicity besides other physiological and molecular defense responses like decrease in growth rate, chlorophyll content and photosynthesis efficiency, intensification of antioxidative mechanisms, regulation of transcription factors, trace elements chelation, and sequestration into vacuole via trace elements transporters. The sole differentially expressed ATP-binding cassette (ABC) transporters indicated that ABC transporters might play a very important role in the transport and relocation of Pb in C. reinhardtii. Additionally, our data provide the required knowledge for future investigations regarding Pb toxicity and defense mechanisms in algae, and detection of trace elements pollution in environment.
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Affiliation(s)
- Canqi Zheng
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Muhammad Aslam
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Xiaojuan Liu
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Hong Du
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Xihui Xie
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Haojie Jia
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Nan Huang
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Kaiming Tang
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Yingquan Yang
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
| | - Ping Li
- Institute of Marine Sciences, Guangdong Provincial Key Laboratory of Marine Biotechnology and STU-UNIVPM Joint Algal Research Center, College of Sciences, Shantou University, Shantou, China.,Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
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The dynamin-like protein Fzl promotes thylakoid fusion and resistance to light stress in Chlamydomonas reinhardtii. PLoS Genet 2019; 15:e1008047. [PMID: 30875368 PMCID: PMC6436760 DOI: 10.1371/journal.pgen.1008047] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 03/27/2019] [Accepted: 02/25/2019] [Indexed: 12/22/2022] Open
Abstract
Large GTPases of the Dynamin Related Proteins (DRP) family shape lipid bilayers through membrane fission or fusion processes. Despite the highly organized photosynthetic membranes of thylakoids, a single DRP is known to be targeted inside the chloroplast. Fzl from the land plant Arabidopsis thaliana is inserted in the inner envelope and thylakoid membranes to regulate their morphology. Fzl may promote the fusion of thylakoids but this remains to be proven. Moreover, the physiological requirement for fusing thylakoids is currently unknown. Here, we find that the unicellular microalga Chlamydomonas reinhardtii encodes an Fzl ortholog (CrFzl) that is localized in the chloroplast where it is soluble. To explore its function, the CRISPR/Cas9 technology was employed to generate multiple CrFzl knock out strains. Phenotypic analyzes revealed a specific requirement of CrFzl for survival upon light stress. Consistent with this, strong irradiance lead to increased photoinhibition of photosynthesis in mutant cells. Fluorescence and electron microscopy analysis demonstrated that upon exposure to high light, CrFzl mutants show defects in chloroplast morphology but also large cytosolic vacuoles in close contact with the plastid. We further observe that strong irradiance induces an increased recruitment of the DRP to thylakoid membranes. Most importantly, we show that CrFzl is required for the fusion of thylakoids during mating. Together, our results suggest that thylakoids fusion may be necessary for resistance to light stress. All eukaryotic cells are composed of compartments with defined functions. Among those, mitochondria generate the main source of energy in human and animal cells. Their capacity to generate and diffuse energy in the cell is regulated by fusion and fragmentation processes. Together with mitochondria that produce energy from oxygen, plant cells include an additional compartment called the chloroplast that produces energy from light. The machinery that converts light into energy is more precisely located inside the chloroplast within stacks of membranes called the thylakoids. Here, we elucidate the function of CrFzl, a previously uncharacterized protein encoded by the genome of the unicellular alga Chlamydomonas reinhardtii. Algal cells that do not contain CrFzl are impaired in their capacity to grow when they receive too much light and our results indicate that CrFzl promotes the fusion of thylakoids during mating. These results suggest that membrane fusion is an essential tool for energy production in stress conditions by living organisms.
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Li Y, Fei X, Dai H, Li J, Zhu W, Deng X. Genome-Wide Identification of Calcium-Dependent Protein Kinases in Chlamydomonas reinhardtii and Functional Analyses in Nitrogen Deficiency-Induced Oil Accumulation. FRONTIERS IN PLANT SCIENCE 2019; 10:1147. [PMID: 31695707 PMCID: PMC6818280 DOI: 10.3389/fpls.2019.01147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/22/2019] [Indexed: 05/15/2023]
Abstract
Calcium-dependent protein kinases (CDPKs) are recognized as important calcium (Ca2+) sensors in signal transduction and play multiple roles in plant growth and developmental processes, as well as in response to various environmental stresses. However, little information is available about the CDPK family in the green microalga Chlamydomonas reinhardtii. In this study, 15 CrCDPK genes were identified in C. reinhardtii genome, and their functions in nitrogen (N) deficiency-induced oil accumulation were analyzed. Our results showed that all CrCDPK proteins harbored the typical elongation factor (EF)-hand Ca2+-binding and protein kinase domains. Phylogenetic analysis revealed that these CrCDPKs were clustered into one group together with a subclade of several CPKs from Arabidopsis and rice, clearly separating from the remaining AtCPKs and OsCPKs. These genes were located in 10 chromosomes and one scaffold of C. reinhardtii and contained 6-17 exons. RNA sequencing and quantitative reverse transcription (qRT)-PCR assays indicated that most of these CrCDPKs were significantly induced by N deficiency and salt stress. Lanthanum chloride (LaCl3), a plasma membrane Ca2+ channel blocker, limited oil accumulation in C. reinhardtii under N-deficient conditions, suggesting that Ca2+ was involved in N deficiency-induced oil accumulation. Furthermore, RNA interference (RNAi) silencing analyses demonstrated that six CrCDPKs played positive roles and three CrCDPKs played negative roles in N deficiency-induced oil accumulation in C. reinhardtii.
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Affiliation(s)
- Yajun Li
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Xiaowen Fei
- Biochemistry and Molecular Biology Department, Hainan Medical College, Haikou, China
| | - Haofu Dai
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Jiangyue Li
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Weiju Zhu
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Xiaodong Deng
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
- *Correspondence: Xiaodong Deng,
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