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He J, Li P, Huo H, Liu L, Tang T, He M, Huang J, Liu L. Heterologous expression of HpBHY and CrBKT increases heat tolerance in Physcomitrella patens. PLANT DIVERSITY 2019; 41:266-274. [PMID: 31528786 PMCID: PMC6742491 DOI: 10.1016/j.pld.2019.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 05/27/2023]
Abstract
Heat stress can restrict plant growth, development, and crop yield. As essential plant antioxidants, carotenoids play significant roles in plant stress resistance. β-carotene hydroxylase (BHY) and β-carotene ketolase (BKT), which catalyze the conversions of β-carotene to zeaxanthin and β-carotene to canthaxanthin, respectively, are key enzymes in the carotenoid biosynthetic pathway, but little is known about their potential functions in stress resistance. Here, we investigated the roles of β-carotene hydroxylase and β-carotene ketolase during heat stress in Physcomitrella patens through expressing a β-carotene ketolase gene from Chlamydomonas reinhardtii (CrBKT) and a β-carotene hydroxylase gene from Haematococcus pluvialis (HpBHY) in the moss P. patens. In transgenic moss expressing these genes, carotenoids content increased (especially lutein content), and heat stress tolerance increased, with reduced leafy tissue necrosis. To investigate the mechanism of this heat stress resistance, we measured various physiological indicators and found a lower malondialdehyde level, higher peroxidase and superoxide dismutase activities, and higher endogenous abscisic acid and salicylate content in the transgenic plants in response to high-temperature stress. These results demonstrate that CrBKT and HpBHY increase plant heat stress resistance through the antioxidant and damage repair metabolism, which is related to abscisic acid and salicylate signaling.
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Affiliation(s)
- Jianfang He
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Li
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Heqiang Huo
- Mid-Florida Research and Education Center, Department of Environmental Horticulture, University of Florida, FL, 32703, USA
| | - Lina Liu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ting Tang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
| | - Mingxia He
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
| | - Junchao Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
| | - Li Liu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
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Ho J, Theg SM. The Formation of Stromules In Vitro from Chloroplasts Isolated from Nicotiana benthamiana. PLoS One 2016; 11:e0146489. [PMID: 26840974 PMCID: PMC4739594 DOI: 10.1371/journal.pone.0146489] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/17/2015] [Indexed: 11/23/2022] Open
Abstract
Stromules are stroma-containing tubules that have been observed to emanate from the main plastidic body in vivo. These structures have been shown to require cytoskeletal components for movement. Though numerous studies have shown a close association with the endoplasmic reticulum, nucleus, mitochondria, and other plastids, the mechanism of formation and their overall function remain unknown. A limiting factor in studying these structures has been the lack of a reconstituted system for in vitro stromule formation. In this study, stromule formation was induced in vitro by adding a plant extract fraction that is greater than 100 kDa to a population of isolated chloroplasts. Kinetic measurements show that stromule formation occurs within ~10 seconds after the addition of the plant extract fraction. Heat inactivation and apyrase treatment reveal that the stromule stimulating compound found in the extract fraction is a protein or protein complex 100 kDa or greater. The formation of the stromules in vitro with isolated chloroplasts and a concentrated fraction of cell extract opens an avenue for the biochemical dissection of this process that has heretofore been studied only in vivo.
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Affiliation(s)
- Jonathan Ho
- Department of Plant Biology, University of California Davis, Davis, California, United States of America
| | - Steven M. Theg
- Department of Plant Biology, University of California Davis, Davis, California, United States of America
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Kwon KC, Verma D, Jin S, Singh ND, Daniell H. Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress. PLoS One 2013; 8:e67106. [PMID: 23799142 PMCID: PMC3682959 DOI: 10.1371/journal.pone.0067106] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 05/15/2013] [Indexed: 12/17/2022] Open
Abstract
Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress) or paraquat (abiotic stress), GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II) made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide), which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These results suggest a novel signaling mechanism, especially for participation of chloroplast proteins (e.g. transcription factors) in retrograde signaling, thereby offering new opportunities to regulate pathways outside chloroplasts.
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Affiliation(s)
- Kwang-Chul Kwon
- Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- Departments of Biochemistry and Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, Pennsylvania, United States of America
| | - Dheeraj Verma
- Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Shuangxia Jin
- Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Nameirakpam D. Singh
- Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
| | - Henry Daniell
- Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Orlando, Florida, United States of America
- Departments of Biochemistry and Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, Pennsylvania, United States of America
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Lo SM, Theg SM. Role of vesicle-inducing protein in plastids 1 in cpTat transport at the thylakoid. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:656-68. [PMID: 22487220 DOI: 10.1111/j.1365-313x.2012.05020.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
VIPP1 has been shown to be required for the proper formation of thylakoid membranes. However, studies on VIPP1 itself, as well as on PspA, its bacterial homolog, suggests that this protein may be involved in a number of additional functions, including protein translocation. The role of VIPP1 in protein translocation in the chloroplast has not been investigated. To this end, we conducted in vitro thylakoid protein transport assays to look at the effect of VIPP1 on the cpTat pathway, which is one of three translocation pathways found in both the chloroplast and its bacterial progenitor. We found that VIPP1 does indeed enhance protein transport through the cpTat pathway by up to 100%. The VIPP1 effect on cpTat activity occurs without interacting with the substrates or components of the translocon, and does not alter the energy potentials driving this translocation pathway. Instead, VIPP1 greatly enhances the amount of substrate bound productively to the thylakoids. Moreover, the presence of increasing VIPP1 concentrations in the reactions resulted in greater interactions between thylakoid membranes. Taken together, these results demonstrate a stimulatory role for VIPP1 in cpTat transport by enhancement of substrate binding, probably to the membrane lipid regions of the thylakoid. We propose a model in which VIPP1 facilitates reorganization of the thylakoid structure to increase substrate access to productive binding regions of the membrane as an early step in the cpTat pathway.
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Affiliation(s)
- Shari M Lo
- Section of Plant Biology, University of California at Davis, Davis, CA 95616, USA
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