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Chen D, Chen J, Dai R, Zheng X, Han Y, Chen Y, Xue T. Integration analysis of ATAC-seq and RNA-seq provides insight into fatty acid biosynthesis in Schizochytrium limacinum under nitrogen limitation stress. BMC Genomics 2024; 25:141. [PMID: 38311722 PMCID: PMC10840233 DOI: 10.1186/s12864-024-10043-5] [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: 06/08/2023] [Accepted: 01/22/2024] [Indexed: 02/06/2024] Open
Abstract
BACKGROUND Schizochytrium limacinum holds significant value utilized in the industrial-scale synthesis of natural DHA. Nitrogen-limited treatment can effectively increase the content of fatty acids and DHA, but there is currently no research on chromatin accessibility during the process of transcript regulation. The objective of this research was to delve into the workings of fatty acid production in S. limacinum by examining the accessibility of promoters and profiling gene expressions. RESULTS Results showed that differentially accessible chromatin regions (DARs)-associated genes were enriched in fatty acid metabolism, signal transduction mechanisms, and energy production. By identifying and annotating DARs-associated motifs, the study obtained 54 target transcription factor classes, including BPC, RAMOSA1, SPI1, MYC, and MYB families. Transcriptomics results revealed that several differentially expressed genes (DEGs), including SlFAD2, SlALDH, SlCAS1, SlNSDHL, and SlDGKI, are directly related to the biosynthesis of fatty acids, meanwhile, SlRPS6KA, SlCAMK1, SlMYB3R1, and SlMYB3R5 serve as transcription factors that could potentially influence the regulation of fatty acid production. In the integration analysis of DARs and ATAC-seq, 13 genes were identified, which were shared by both DEGs and DARs-associated genes, including SlCAKM, SlRP2, SlSHOC2, SlTN, SlSGK2, SlHMP, SlOGT, SlclpB, and SlDNAAF3. CONCLUSIONS SlCAKM may act as a negative regulator of fatty acid and DHA synthesis, while SlSGK2 may act as a positive regulator, which requires further study in the future. These insights enhance our comprehension of the processes underlying fatty acid and DHA production in S. limacinum. They also supply a foundational theoretical framework and practical assistance for the development of strains rich in fatty acids and DHA.
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Affiliation(s)
- Duo Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Jing Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Rongchun Dai
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Xuehai Zheng
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Yuying Han
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Youqiang Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China
| | - Ting Xue
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Products of the State Oceanic Administration, Center of Engineering Technology Research for Microalga Germplasm Improvement of Fujian, Fujian Key Laboratory of Special Marine Bioresource Sustainable Utilization, College of Life Sciences, Fujian Normal University, Fuzhou, China.
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Konte T, Terpitz U, Plemenitaš A. Reconstruction of the High-Osmolarity Glycerol (HOG) Signaling Pathway from the Halophilic Fungus Wallemia ichthyophaga in Saccharomyces cerevisiae. Front Microbiol 2016; 7:901. [PMID: 27379041 PMCID: PMC4904012 DOI: 10.3389/fmicb.2016.00901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/26/2016] [Indexed: 11/13/2022] Open
Abstract
The basidiomycetous fungus Wallemia ichthyophaga grows between 1.7 and 5.1 M NaCl and is the most halophilic eukaryote described to date. Like other fungi, W. ichthyophaga detects changes in environmental salinity mainly by the evolutionarily conserved high-osmolarity glycerol (HOG) signaling pathway. In Saccharomyces cerevisiae, the HOG pathway has been extensively studied in connection to osmotic regulation, with a valuable knock-out strain collection established. In the present study, we reconstructed the architecture of the HOG pathway of W. ichthyophaga in suitable S. cerevisiae knock-out strains, through heterologous expression of the W. ichthyophaga HOG pathway proteins. Compared to S. cerevisiae, where the Pbs2 (ScPbs2) kinase of the HOG pathway is activated via the SHO1 and SLN1 branches, the interactions between the W. ichthyophaga Pbs2 (WiPbs2) kinase and the W. ichthyophaga SHO1 branch orthologs are not conserved: as well as evidence of poor interactions between the WiSho1 Src-homology 3 (SH3) domain and the WiPbs2 proline-rich motif, the absence of a considerable part of the osmosensing apparatus in the genome of W. ichthyophaga suggests that the SHO1 branch components are not involved in HOG signaling in this halophilic fungus. In contrast, the conserved activation of WiPbs2 by the S. cerevisiae ScSsk2/ScSsk22 kinase and the sensitivity of W. ichthyophaga cells to fludioxonil, emphasize the significance of two-component (SLN1-like) signaling via Group III histidine kinase. Combined with protein modeling data, our study reveals conserved and non-conserved protein interactions in the HOG signaling pathway of W. ichthyophaga and therefore significantly improves the knowledge of hyperosmotic signal processing in this halophilic fungus.
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Affiliation(s)
- Tilen Konte
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana Ljubljana, Slovenia
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University of Würzburg Würzburg, Germany
| | - Ana Plemenitaš
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana Ljubljana, Slovenia
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Wang ZY, Gehring C, Zhu J, Li FM, Zhu JK, Xiong L. The Arabidopsis Vacuolar Sorting Receptor1 is required for osmotic stress-induced abscisic acid biosynthesis. PLANT PHYSIOLOGY 2015; 167:137-52. [PMID: 25416474 PMCID: PMC4281004 DOI: 10.1104/pp.114.249268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.
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Affiliation(s)
- Zhen-Yu Wang
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
| | - Chris Gehring
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
| | - Jianhua Zhu
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
| | - Feng-Min Li
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
| | - Jian-Kang Zhu
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
| | - Liming Xiong
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Z.-Y.W., C.G., L.X.);State Key Laboratory of Grassland Agroecosystem, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China (Z.-Y.W., F.-M.L.);Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742 (J.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907 (J.-K.Z.); andShanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (J.-K.Z.)
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Forde BG. Nitrogen signalling pathways shaping root system architecture: an update. CURRENT OPINION IN PLANT BIOLOGY 2014; 21:30-36. [PMID: 24997289 DOI: 10.1016/j.pbi.2014.06.004] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 06/12/2014] [Indexed: 05/03/2023]
Abstract
Root system architecture is a fundamentally important trait for resource acquisition in both ecological and agronomic contexts. Because of the plasticity of root development and the almost infinite complexity of the soil, root system architecture is shaped by environmental factors to a much greater degree than shoot architecture. In attempting to understand how roots sense and respond to environmental cues, the striking effects of nitrate and other forms of nitrogen on root growth and branching have received particular attention. This minireview focuses on the latest advances in our understanding of the diverse nitrogen signalling pathways that are now known to act at multiple stages in the process of lateral root development, as well as on primary root growth.
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Affiliation(s)
- Brian G Forde
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
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Abstract
As a signalling molecule, glutamate is best known for its role as a fast excitatory neurotransmitter in the mammalian nervous system, a role that requires the activity of a family of ionotropic glutamate receptors (iGluRs). The unexpected discovery in 1998 that Arabidopsis thaliana L. possesses a family of iGluR-related (GLR) genes laid the foundations for an assessment of glutamate's potential role as a signalling molecule in plants that is still in progress. Recent advances in elucidating the function of Arabidopsis GLR receptors has revealed similarities with iGluRs in their channel properties, but marked differences in their ligand specificities. The ability of plant GLR receptors to act as amino-acid-gated Ca(2+) channels with a broad agonist profile, combined with their expression throughout the plant, makes them strong candidates for a multiplicity of amino acid signalling roles. Although root growth is inhibited in the presence of a number of amino acids, only glutamate elicits a specific sequence of changes in growth, root tip morphology, and root branching. The recent finding that the MEKK1 gene is a positive regulator of glutamate sensitivity at the root tip has provided genetic evidence for the existence in plants of a glutamate signalling pathway analogous to those found in animals. This short review will discuss the most recent advances in understanding glutamate signalling in roots, considering them in the context of previous work in plants and animals.
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Affiliation(s)
- Brian G Forde
- Centre for Sustainable Agriculture, Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
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Identification and characterization of a salt stress-inducible zinc finger protein from Festuca arundinacea. BMC Res Notes 2012; 5:66. [PMID: 22272737 PMCID: PMC3305619 DOI: 10.1186/1756-0500-5-66] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 01/24/2012] [Indexed: 11/21/2022] Open
Abstract
Background Increased biotic and abiotic plant stresses due to climate change together with an expected global human population of over 9 billion by 2050 intensifies the demand for agricultural production on marginal lands. Soil salinity is one of the major abiotic stresses responsible for reduced crop productivity worldwide and the salinization of arable land has dramatically increased over the last few decades. Consequently, as land becomes less amenable for conventional agriculture, plants grown on marginal soils will be exposed to higher levels of soil salinity. Forage grasses are a critical component of feed used in livestock production worldwide, with many of these same species of grasses being utilized for lawns, erosion prevention, and recreation. Consequently, it is important to develop a better understanding of salt tolerance in forage and related grass species. Findings A gene encoding a ZnF protein was identified during the analysis of a salt-stress suppression subtractive hybridization (SSH) expression library from the forage grass species Festuca arundinacea. The expression pattern of FaZnF was compared to that of the well characterized gene for delta 1-pyrroline-5-carboxylate synthetase (P5CS), a key enzyme in proline biosynthesis, which was also identified in the salt-stress SSH library. The FaZnF and P5CS genes were both up-regulated in response to salt and drought stresses suggesting a role in dehydration stress. FaZnF was also up-regulated in response to heat and wounding, suggesting that it might have a more general function in multiple abiotic stress responses. Additionally, potential downstream targets of FaZnF (a MAPK [Mitogen-Activated Protein Kinase], GST [Glutathione-S-Transferase] and lipoxygenase L2) were found to be up-regulated in calli overexpressing FaZnF when compared to control cell lines. Conclusions This work provides evidence that FaZnF is an AN1/A20 zinc finger protein that is involved in the regulation of at least two pathways initiated by the salt stress response, thus furthering our understanding of the mechanisms of cellular action during a stress that is applicable to commercial crops worldwide.
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Wang Q, Han C, Ferreira AO, Yu X, Ye W, Tripathy S, Kale SD, Gu B, Sheng Y, Sui Y, Wang X, Zhang Z, Cheng B, Dong S, Shan W, Zheng X, Dou D, Tyler BM, Wang Y. Transcriptional programming and functional interactions within the Phytophthora sojae RXLR effector repertoire. THE PLANT CELL 2011; 23:2064-86. [PMID: 21653195 PMCID: PMC3160037 DOI: 10.1105/tpc.111.086082] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 04/05/2011] [Accepted: 05/25/2011] [Indexed: 05/18/2023]
Abstract
The genome of the soybean pathogen Phytophthora sojae contains nearly 400 genes encoding candidate effector proteins carrying the host cell entry motif RXLR-dEER. Here, we report a broad survey of the transcription, variation, and functions of a large sample of the P. sojae candidate effectors. Forty-five (12%) effector genes showed high levels of polymorphism among P. sojae isolates and significant evidence for positive selection. Of 169 effectors tested, most could suppress programmed cell death triggered by BAX, effectors, and/or the PAMP INF1, while several triggered cell death themselves. Among the most strongly expressed effectors, one immediate-early class was highly expressed even prior to infection and was further induced 2- to 10-fold following infection. A second early class, including several that triggered cell death, was weakly expressed prior to infection but induced 20- to 120-fold during the first 12 h of infection. The most strongly expressed immediate-early effectors could suppress the cell death triggered by several early effectors, and most early effectors could suppress INF1-triggered cell death, suggesting the two classes of effectors may target different functional branches of the defense response. In support of this hypothesis, misexpression of key immediate-early and early effectors severely reduced the virulence of P. sojae transformants.
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Affiliation(s)
- Qunqing Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Changzhi Han
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Adriana O. Ferreira
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
| | - Xiaoli Yu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Sucheta Tripathy
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
| | - Shiv D. Kale
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
| | - Biao Gu
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yuting Sheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yangyang Sui
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoli Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhengguang Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Baoping Cheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Weixing Shan
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaobo Zheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing 210095, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing 210095, China
| | - Brett M. Tyler
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia 24061
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing 210095, China
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Ning J, Li X, Hicks LM, Xiong L. A Raf-like MAPKKK gene DSM1 mediates drought resistance through reactive oxygen species scavenging in rice. PLANT PHYSIOLOGY 2010; 152:876-90. [PMID: 20007444 PMCID: PMC2815886 DOI: 10.1104/pp.109.149856] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/02/2009] [Indexed: 05/18/2023]
Abstract
Mitogen-activated protein kinase (MAPK) cascades have been identified in various signaling pathways involved in plant development and stress responses. We identified a drought-hypersensitive mutant (drought-hypersensitive mutant1 [dsm1]) of a putative MAPK kinase kinase (MAPKKK) gene in rice (Oryza sativa). Two allelic dsm1 mutants were more sensitive than wild-type plants to drought stress at both seedling and panicle development stages. The dsm1 mutants lost water more rapidly than wild-type plants under drought stress, which was in agreement with the increased drought-sensitivity phenotype of the mutant plants. DSM1-RNA interference lines were also hypersensitive to drought stress. The predicted DSM1 protein belongs to a B3 subgroup of plant Raf-like MAPKKKs and was localized in the nucleus. By real-time PCR analysis, the DSM1 gene was induced by salt, drought, and abscisic acid, but not by cold. Microarray analysis revealed that two peroxidase (POX) genes, POX22.3 and POX8.1, were sharply down-regulated compared to wild type, suggesting that DSM1 may be involved in reactive oxygen species (ROS) signaling. Peroxidase activity, electrolyte leakage, chlorophyll content, and 3,3'-diaminobenzidine staining revealed that the dsm1 mutant was more sensitive to oxidative stress due to an increase in ROS damage caused by the reduced POX activity. Overexpression of DSM1 in rice increased the tolerance to dehydration stress at the seedling stage. Together, these results suggest that DSM1 might be a novel MAPKKK functioning as an early signaling component in regulating responses to drought stress by regulating scavenging of ROS in rice.
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Jain D, Roy N, Chattopadhyay D. CaZF, a plant transcription factor functions through and parallel to HOG and calcineurin pathways in Saccharomyces cerevisiae to provide osmotolerance. PLoS One 2009; 4:e5154. [PMID: 19365545 PMCID: PMC2664467 DOI: 10.1371/journal.pone.0005154] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 03/13/2009] [Indexed: 01/19/2023] Open
Abstract
Salt-sensitive yeast mutants were deployed to characterize a gene encoding a C2H2 zinc finger protein (CaZF) that is differentially expressed in a drought-tolerant variety of chickpea (Cicer arietinum) and provides salinity-tolerance in transgenic tobacco. In Saccharomyces cerevisiae most of the cellular responses to hyper-osmotic stress is regulated by two interconnected pathways involving high osmolarity glycerol mitogen-activated protein kinase (Hog1p) and Calcineurin (CAN), a Ca(2+)/calmodulin-regulated protein phosphatase 2B. In this study, we report that heterologous expression of CaZF provides osmotolerance in S. cerevisiae through Hog1p and Calcineurin dependent as well as independent pathways. CaZF partially suppresses salt-hypersensitive phenotypes of hog1, can and hog1can mutants and in conjunction, stimulates HOG and CAN pathway genes with subsequent accumulation of glycerol in absence of Hog1p and CAN. CaZF directly binds to stress response element (STRE) to activate STRE-containing promoter in yeast. Transactivation and salt tolerance assays of CaZF deletion mutants showed that other than the transactivation domain a C-terminal domain composed of acidic and basic amino acids is also required for its function. Altogether, results from this study suggests that CaZF is a potential plant salt-tolerance determinant and also provide evidence that in budding yeast expression of HOG and CAN pathway genes can be stimulated in absence of their regulatory enzymes to provide osmotolerance.
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Affiliation(s)
- Deepti Jain
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Nilanjan Roy
- National Institute for Pharmaceutical Education and Research, SAS Nagar, Punjab, India
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Pitzschke A, Djamei A, Bitton F, Hirt H. A major role of the MEKK1-MKK1/2-MPK4 pathway in ROS signalling. MOLECULAR PLANT 2009; 2:120-37. [PMID: 19529823 PMCID: PMC2639734 DOI: 10.1093/mp/ssn079] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 10/24/2008] [Indexed: 05/18/2023]
Abstract
Over the last few years, it has become evident that reactive oxygen species (ROS) signalling plays an important role in various physiological responses, including pathogen defense and stomatal opening/closure. On the other hand, ROS overproduction is detrimental for proper plant growth and development, indicating that the regulation of an appropriate redox balance is essential for plants. ROS homeostasis in plants involves the mitogen-activated protein kinase (MAPK) pathway consisting of the MAPK kinase kinase MEKK1 and the MAPK MPK4. Phenotypic and molecular analysis revealed that the MAPK kinases MKK1 and MKK2 are part of a cascade, regulating ROS and salicylic acid (SA) accumulation. Gene expression analysis shows that of 32 transcription factors reported to be highly responsive to multiple ROS-inducing conditions, 20 are regulated by the MEKK1, predominantly via the MEKK1-MKK1/2-MPK4 pathway. However, MEKK1 also functions on other as yet unknown pathways and part of the MEKK1-dependent MPK4 responses are regulated independently of MKK1 and MKK2. Overall, this analysis emphasizes the central role of this MAPK cascade in oxidative stress signalling, but also indicates the high level of complexity revealed by this signalling network.
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Affiliation(s)
- Andrea Pitzschke
- Department of Plant Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Dr.-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Armin Djamei
- Department of Plant Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Dr.-Bohr-Gasse 9, 1030 Vienna, Austria
- Present address: Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Frédérique Bitton
- URGV Plant Genomics Laboratory, 2 Rue Gaston Crémieux, 91057 Evry, France
| | - Heribert Hirt
- Department of Plant Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Dr.-Bohr-Gasse 9, 1030 Vienna, Austria
- URGV Plant Genomics Laboratory, 2 Rue Gaston Crémieux, 91057 Evry, France
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Suarez-Rodriguez MC, Adams-Phillips L, Liu Y, Wang H, Su SH, Jester PJ, Zhang S, Bent AF, Krysan PJ. MEKK1 is required for flg22-induced MPK4 activation in Arabidopsis plants. PLANT PHYSIOLOGY 2007; 143:661-9. [PMID: 17142480 PMCID: PMC1803745 DOI: 10.1104/pp.106.091389] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) gene MEKK1 encodes a mitogen-activated protein kinase kinase kinase that has been implicated in the activation of the map kinases MPK3 and MPK6 in response to the flagellin elicitor peptide flg22. In this study, analysis of plants carrying T-DNA knockout alleles indicated that MEKK1 is required for flg22-induced activation of MPK4 but not MPK3 or MPK6. Experiments performed using a kinase-impaired version of MEKK1 (K361M) showed that the kinase activity of MEKK1 may not be required for flg22-induced MPK4 activation or for other macroscopic FLS2-mediated responses. MEKK1 may play a structural role in signaling, independent of its protein kinase activity. mekk1 knockout mutants display a severe dwarf phenotype, constitutive callose deposition, and constitutive expression of pathogen response genes. This dwarf phenotype was largely rescued by introduction into mekk1 knockout plants of either the MEKK1 (K361M) construct or a nahG transgene that degrades salicylic acid. When treated with pathogenic bacteria, the K361M plants were slightly more susceptible to an avirulent strain of Pseudomonas syringae and showed a delayed hypersensitive response, suggesting a role for MEKK1 kinase activity in this aspect of plant disease resistance. Our results indicate that MEKK1 acts upstream of MPK4 as a negative regulator of pathogen response pathways, a function that may not require MEKK1's full kinase activity.
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Mishra NS, Tuteja R, Tuteja N. Signaling through MAP kinase networks in plants. Arch Biochem Biophys 2006; 452:55-68. [PMID: 16806044 DOI: 10.1016/j.abb.2006.05.001] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 05/04/2006] [Accepted: 05/05/2006] [Indexed: 01/01/2023]
Abstract
Protein phosphorylation is the most important mechanism for controlling many fundamental cellular processes in all living organisms including plants. A specific class of serine/threonine protein kinases, the mitogen-activated protein kinases (MAP kinases) play a central role in the transduction of various extra- and intracellular signals and are conserved throughout eukaryotes. These generally function via a cascade of networks, where MAP kinase (MAPK) is phosphorylated and activated by MAPK kinase (MAPKK), which itself is activated by MAPKK kinase (MAPKKK). Signaling through MAP kinase cascade can lead to cellular responses including cell division, differentiation as well as response to various stresses. In plants, MAP kinases are represented by multigene families and are organized into a complex network for efficient transmission of specific stimuli. Putative plant MAP kinase cascades have been postulated based on experimental analysis of in vitro interactions between specific MAP kinase components. These cascades have been tested in planta following expression of epitope-tagged kinases in protoplasts. It is known that signaling for cell division and stress responses in plants are mediated through MAP kinases and even auxin, ABA and possibly ethylene and cytokinin also utilize a MAP kinase pathway. Most of the biotic (pathogens and pathogen-derived elicitors) including wounding and abiotic stresses (salinity, cold, drought, and oxidative) can induce defense responses in plants through MAP kinase pathways. In this article we have covered the historical background, biochemical assay, activation/inactivation, and targets of MAP kinases with emphasis on plant MAP kinases and the responses regulated by them. The cross-talk between plant MAP kinases is also discussed to bring out the complexity within this three-component module.
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Affiliation(s)
- Neeti Sanan Mishra
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Droillard MJ, Boudsocq M, Barbier-Brygoo H, Laurière C. Involvement of MPK4 in osmotic stress response pathways in cell suspensions and plantlets of Arabidopsis thaliana: activation by hypoosmolarity and negative role in hyperosmolarity tolerance. FEBS Lett 2004; 574:42-8. [PMID: 15358537 DOI: 10.1016/j.febslet.2004.08.001] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 07/30/2004] [Accepted: 08/03/2004] [Indexed: 11/28/2022]
Abstract
Three of the protein kinases activated by hypoosmotic stress in Arabidopsis thaliana cell suspensions were previously characterized [FEBS, 2002, 527, 43-50] as mitogen-activated protein (MAP) kinases and two of them corresponded to Arabidopsis mitogen-activated protein kinase 6 (MPK6) (44 kDa) and MPK3 (39 kDa). The third MAP kinase was identified here to MPK4, using a corresponding specific antibody. Like MPK6 and MPK3, MPK4 activity is clearly inhibited by apigenin and MPK4 activation by hypoosmolarity needs upstream phosphorylation events. Activation of the 3 MAP kinases, MPK3, 4 and 6, was confirmed in plantlets submitted to hypoosmotic stress. The action of a biotic signal, flagellin, was also demonstrated to induce the activations of the 3 MAP kinases. Using the mutant displaying MPK4 gene inactivation, the independence of the MPK3 and MPK6 activations towards the presence of MPK4 was demonstrated, both in hypoosmotic and flagellin signalling pathways. Although MPK4 was not activated by hyperosmolarity in cell suspensions nor in seedlings, a possible negative regulation of hyperosmolarity resistance by MPK4 is suggested, based both on phenotype and downstream gene expression studies.
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Affiliation(s)
- Marie-Jo Droillard
- Institut des Sciences du Végétal, UPR 2355, CNRS, 1 av. de la terrasse, 91198 Gif s/Yvette Cedex, France
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Boudsocq M, Barbier-Brygoo H, Laurière C. Identification of nine sucrose nonfermenting 1-related protein kinases 2 activated by hyperosmotic and saline stresses in Arabidopsis thaliana. J Biol Chem 2004; 279:41758-66. [PMID: 15292193 DOI: 10.1074/jbc.m405259200] [Citation(s) in RCA: 285] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several calcium-independent protein kinases were activated by hyperosmotic and saline stresses in Arabidopsis cell suspension. Similar activation profiles were also observed in seedlings exposed to hyperosmotic stress. One of them was identified to AtMPK6 but the others remained to be identified. They were assumed to belong to the SNF1 (sucrose nonfermenting 1)-related protein kinase 2 (SnRK2) family, which constitutes a plant-specific kinase group. The 10 Arabidopsis SnRK2 were expressed both in cells and seedlings, making the whole SnRK2 family a suitable candidate. Using a family-specific antibody raised against the 10 SnRK2, we demonstrated that these non-MAPK protein kinases activated by hyperosmolarity in cell suspension were SnRK2 proteins. Then, the molecular identification of the involved SnRK2 was investigated by transient expression assays. Nine of the 10 SnRK2 were activated by hyperosmolarity induced by mannitol, as well as NaCl, indicating an important role of the SnRK2 family in osmotic signaling. In contrast, none of the SnRK2 were activated by cold treatment, whereas abscisic acid only activated five of the nine SnRK2. The probable involvement of the different Arabidopsis SnRK2 in several abiotic transduction pathways is discussed.
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Affiliation(s)
- Marie Boudsocq
- Institut des Sciences du Végétal, UPR 2355, CNRS, 1 Ave de la Terrasse, 91198 Gif/Yvette Cedex, France
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Lew RR. Osmotic effects on the electrical properties of Arabidopsis root hair vacuoles in situ. PLANT PHYSIOLOGY 2004; 134:352-60. [PMID: 14730070 PMCID: PMC316314 DOI: 10.1104/pp.103.031427] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Revised: 09/04/2003] [Accepted: 09/22/2003] [Indexed: 05/18/2023]
Abstract
To assess the role of the vacuole in responses to hyperosmotic and hypo-osmotic stress, the electrical properties of the vacuole were measured in situ. A double-barrel micropipette was inserted into the vacuole for voltage clamping. A second double-barrel micropipette was inserted into the cytoplasm to provide a virtual ground that separated the electrical properties of the vacuole from those of the plasma membrane. Osmotic stress causes immediate electrical responses at the plasma membrane (Lew RR [1996] Plant Physiol 97: 2002-2005) and ion flux changes and turgor recovery (Shabala SN, Lew RR [2002] 129: 290-299) in Arabidopsis root cells. In situ, the vacuole also responds rapidly to changes in extracellular osmotic potential. Hyperosmotic treatment caused a very large increase in the ionic conductance of the vacuole. Hypo-osmotic treatment did not affect the vacuolar conductance. In either case, the vacuolar electrical potential was unchanged. Taken in concert with previous studies of changes at the plasma membrane, these results demonstrate a highly coordinated system in which the vacuole and plasma membrane are primed to respond immediately to hyperosmotic stress before changes in gene expression.
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Affiliation(s)
- Roger R Lew
- Biology Department, York University, Toronto, Ontario M3J 1P3, Canada.
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Abstract
Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are shading light on the molecular nature of salt tolerance effectors and regulatory pathways.
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Affiliation(s)
- Liming Xiong
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, Tel. (520) 626-2229, Fax (520) 621-7186,
| | - Jian-Kang Zhu
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, Tel. (520) 626-2229, Fax (520) 621-7186,
- Corresponding author
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Shabala SN, Lew RR. Turgor regulation in osmotically stressed Arabidopsis epidermal root cells. Direct support for the role of inorganic ion uptake as revealed by concurrent flux and cell turgor measurements. PLANT PHYSIOLOGY 2002; 129:290-9. [PMID: 12011359 PMCID: PMC155892 DOI: 10.1104/pp.020005] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Accepted: 01/14/2002] [Indexed: 05/05/2023]
Abstract
Hyperosmotic stress is known to significantly enhance net uptake of inorganic ions into plant cells. Direct evidence for cell turgor recovery via such a mechanism, however, is still lacking. In the present study, we performed concurrent measurements of net ion fluxes (with the noninvasive microelectrode ion flux estimation technique) and cell turgor changes (with the pressure-probe technique) to provide direct evidence that inorganic ion uptake regulates turgor in osmotically stressed Arabidopsis epidermal root cells. Immediately after onset of hyperosmotic stress (100/100 mM mannitol/sorbitol treatment), the cell turgor dropped from 0.65 to about 0.25 MPa. Turgor recovery started within 2 to 10 min after the treatment and was accompanied by a significant (30-80 nmol m-2 s-1) increase in uptake of K+, Cl-, and Na+ by root cells. In most cells, almost complete (>90% of initial values) recovery of the cell turgor was observed within 40 to 50 min after stress onset. In another set of experiments, we combined the voltage-clamp and the microelectrode ion flux estimation techniques to show that this process is, in part, mediated by voltage-gated K+ transporters at the cell plasma membrane. The possible physiological significance of these findings is discussed.
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Affiliation(s)
- Sergey N Shabala
- School of Agricultural Science, University of Tasmania, Hobart, Australia
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Abstract
Mitogen activated protein kinases (MAPK) are important mediators in signal transmission, connecting the perception of external stimuli to cellular responses. MAPK cascades are involved in signalling various biotic and abiotic stresses, like wounding and pathogen infection, temperature stress or drought, but are also involved in mediating the action of some plant hormones, such as ethylene and auxin. Moreover, MAPKs have been implicated in cell cycle and developmental processes. In Arabidopsis mutant screens and in vivo assays several components of plant MAPK cascades have been identified. This review gives an update of recent advances in plant MAPK signalling and discusses the emerging mechanisms of some selected MAPK pathways.
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Affiliation(s)
- K Zwerger
- Institute of Microbiology and Genetics, Vienna Biocenter, Austria
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Abstract
The mitogen-activated protein kinase (MAP kinase) signal transduction cascades are routes through which eukaryotic cells deliver extracellular messages to the cytosol and nucleus. These signalling pathways direct cell division, cellular differentiation, metabolism, and both biotic and abiotic stress responses. In plants, MAP kinases and the upstream components of the cascades are represented by multigene families, organized into different pathways which are stimulated and interact in complex ways. Experimental strategies for the analysis of MAP kinase cascades include the yeast two-hybrid system; using this approach in vitro interactions between specific MAP kinase cascade components have been analysed and putative plant cascades postulated. Transient transformation of protoplasts with epitope-tagged kinases has allowed cascades to be tested in planta. There is clear evidence for the involvement of MAP kinases in plant cell division and in the regulation of auxin signalling. Biotic (pathogens and pathogen-derived elicitors from fungi, bacteria and viruses) and abiotic stresses including wounding, mechanical stimulation, cold, drought and ozone can elicit defence responses in plants through MAP kinase pathways. There are data suggesting that ABA signalling utilizes a MAP kinase pathway, and probably ethylene and perhaps cytokinins do so also. The objective of this paper is to review this rapidly advancing field. Contents Summary 67 I. Introduction 68 II. Background 68 III. MAP kinase targets and targeting specificity 69 IV. Assays and inhibitors 70 V. Two well characterized MAP kinase pathways, Hog1 and Sevenless 71 VI. MAP kinases in plants 73 VII. MAP kinases and cell division 76 VIII. MAP kinases and plant hormones 76 IX. MAP kinase and abiotic stress 78 X. MAP kinase and biotic stress 80 XI. Future perspectives for MAP kinase research in plants 83 Acknowledgements 84 References 84.
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Affiliation(s)
- Peter C Morris
- Heriot-Watt University, Department of Biological Sciences, Riccarton, Edinburgh, EH14 4AS
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Xiong L, Zhu JK. Abiotic stress signal transduction in plants: Molecular and genetic perspectives. PHYSIOLOGIA PLANTARUM 2001; 112:152-166. [PMID: 11454221 DOI: 10.1034/j.1399-3054.2001.1120202.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Low temperature, drought and salinity are major adverse environmental factors that limit plant productivity. Understanding the mechanisms by which plants perceive and transduce these stress signals to initiate adaptive responses is essential for engineering stress-tolerant crop plants. Molecular and biochemical studies suggest that abiotic stress signaling in plants involves receptor-coupled phosphorelay, phosphoinositol-induced Ca2+ changes, mitogen-activated protein kinase cascades and transcriptional activation of stress-responsive genes. In addition, protein posttranslational modifications and adapter or scaffold-mediated protein-protein interactions are also important in abiotic stress signal transduction. Most of these signaling modules, however, have not been genetically established to function in plant abiotic stress signal transduction. To overcome the scarcity of abiotic stress-specific phenotypes for conventional genetic screens, molecular genetic analysis using stress-responsive promoter-driven reporter is suggested as an alternative approach to genetically dissect abiotic stress signaling networks in plants.
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Affiliation(s)
- Liming Xiong
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
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Rai SP, Luthra R, Gupta MM, Kumar S. Pleiotropic morphological and abiotic stress resistance phenotypes of the hyper-abscisic acid producing Abo- mutant in the periwinkle Catharanthus roseus. J Biosci 2001; 26:57-70. [PMID: 11255514 DOI: 10.1007/bf02708981] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The pleiotropic properties of a abo abo (Abo-) gamma-ray induced mutant of Catharanthus roseus cv. Nirmal, selected among the M2 generation seeds for ability to germinate at 45 degrees C, are described. The mutant produced seeds possessing tricotyledonous embryos, unlike the typically dicotyledonous embryos present in the wild type Abo+ seeds. In comparison to Abo+ adults, the mutant plants had short stature and lanceolate leaves. The vascular bundles in the leaves and stem were poorly developed. Leaf surfaces were highly trichomatous, epidermal, cortex and mesophyll cells were small sized and a large majority of stomata were closed. Besides high temperature, the mutant was salinity and water-stress tolerant. The abscisic acid (ABA) content in the leaves was about 500-fold higher. The genetic lesion abo responsible for the above pleiotropy was recessive and inherited in Mendelian fashion. The seedlings and adult plants of the mutant accumulated higher proline than Abo+ plants. The phenotypes of abo abo mutants permitted the conclusions that (i) the mutant synthesizes ABA constitutively, (ii) both ABA-dependent and ABA independent pathways for proline and betaine accumulation are functional in the mutant, and (iii) cell division, elongation and differentiation processes in embryo and adult plant stages are affected in the mutant
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Affiliation(s)
- S P Rai
- Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow 226 015, India
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