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Gaoshan Y, Na L, Dong D, Shuaishuai W, Peng L, Shengfang H, Dongmei W. Functional characterization of the Wrab17 gene in the interaction process between wheat and Puccinia triticina. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 133:100-106. [PMID: 30399543 DOI: 10.1016/j.plaphy.2018.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/14/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
In the interaction between wheat and Puccinia triticina, wheat resists the invasion of P. triticina by producing hypersensitive reaction-programmed cell death (HR-PCD). To better understand the mechanism of wheat resistance to P. triticina, it is important to identify the defensive genes involved in wheat resistance to leaf rust. This paper systematically presented the role of Wrab17 in the HR-PCD process in wheat after infection by P. triticina. The subcellular location analysis is performed using the full length of Wrab17 coding sequences and Wrab17 is found to be localized in cell nucleus and cytoplasm. Quantitative RT-PCR (RT-qPCR) and western blot analysis showed that expression of Wrab17 at both mRNA and protein levels increased by P. triticina infection, indicating that the Wrab17 gene participated in the interaction between wheat and P. triticina. Wrab17 knockdown plants were generated by RNA-mediated gene silencing technology (RNA interference, RNAi) and confirmed by southern blot. Further analysis with P. triticina inoculation found that knockdown of Wrab17 exhibited decreased HR expansion area in incompatible combination (L10×260) and significant higher sensitivity to the compatible pathogen P. triticina race 165. In all, this work reports that Wrab17 is a new defensive gene playing a role in wheat resistance to leaf rust.
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Affiliation(s)
- Yang Gaoshan
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China; Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, 050017, China
| | - Liu Na
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China
| | - Ding Dong
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China
| | - Wang Shuaishuai
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China; Maize Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Liu Peng
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China; Berry Genomics Corporation, The Second Hospital of Hebei Medical University, Shijiazhuang, 050017, China
| | - Han Shengfang
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China.
| | - Wang Dongmei
- Key Laboratory of Hebei Province for Plant Physiology and Molecular Pathology, College of Life Sciences, Hebei Agricultural University, Baoding, 071001, China.
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Wang X, Zhang L, Zhang Y, Bai Z, Liu H, Zhang D. Triticum aestivum WRAB18 functions in plastids and confers abiotic stress tolerance when overexpressed in Escherichia coli and Nicotiania benthamiana. PLoS One 2017; 12:e0171340. [PMID: 28207772 PMCID: PMC5313140 DOI: 10.1371/journal.pone.0171340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/19/2017] [Indexed: 01/08/2023] Open
Abstract
WRAB18, an ABA-inducible protein belongs to the third family of late embryogenesis abundant (LEA) proteins which can be induced by different biotic or abiotic stresses. In the present study, WRAB18 was cloned from the Zhengyin 1 cultivar of Triticum aestivum and overexpressed in Escherichia coli to explore its effects on the growth of E. coli under different abiotic stresses. Results suggested the enhanced exhibition of tolerance of E. coli to these stresses. Meanwhile, the WRAB18-transgenic tobacco plants were obtained to analyze the stress-related enzymatic activities of ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD), and to quantify the content of malonaldehyde (MDA) under osmotic stress, high salinity, and low and high temperature stress. The activities of APX, POD and SOD in the transgenic tobacco lines were higher while the content of MDA was lower than those of WT lines. Moreover, plastid localization of WRAB18 in Nicotiana benthamiana plasma cells were found fusing with GFP. In addition, purified WRAB18 protein protected LDH (Lactate dehydrogenase) enzyme activity in vitro from various stress conditions. In brief, WRAB18 protein shows protective action behaving as a "molecular shield" in both prokaryotic and eukaryotic cells under various abiotic stresses, not only during ABA stress.
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Affiliation(s)
- Xiaoyu Wang
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
| | - Linsheng Zhang
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
| | - Yane Zhang
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
| | - Zhenqing Bai
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
| | - Hao Liu
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
| | - Dapeng Zhang
- College of Life Sciences/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A & F University, Yangling, China
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Brychkova G, Yarmolinsky D, Batushansky A, Grishkevich V, Khozin-Goldberg I, Fait A, Amir R, Fluhr R, Sagi M. Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves. PLANTS 2015; 4:573-605. [PMID: 27135342 PMCID: PMC4844397 DOI: 10.3390/plants4030573] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 07/30/2015] [Accepted: 08/07/2015] [Indexed: 11/24/2022]
Abstract
Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S) metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA), Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA) cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants.
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Affiliation(s)
- Galina Brychkova
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Dmitry Yarmolinsky
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Albert Batushansky
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Vladislav Grishkevich
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Inna Khozin-Goldberg
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Aaron Fait
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
| | - Rachel Amir
- Migal-Galilee Technology Center, Southern Industrial Zone, POB831 Kiryat-Shmona 11016, Israel.
| | - Robert Fluhr
- Department of Plant Sciences, Weizmann Institute of Science, P.O.B. 26 Rehovot 76100, Israel.
| | - Moshe Sagi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
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Watanabe M, Balazadeh S, Tohge T, Erban A, Giavalisco P, Kopka J, Mueller-Roeber B, Fernie AR, Hoefgen R. Comprehensive dissection of spatiotemporal metabolic shifts in primary, secondary, and lipid metabolism during developmental senescence in Arabidopsis. PLANT PHYSIOLOGY 2013; 162:1290-310. [PMID: 23696093 PMCID: PMC3707545 DOI: 10.1104/pp.113.217380] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/17/2013] [Indexed: 05/17/2023]
Abstract
Developmental senescence is a coordinated physiological process in plants and is critical for nutrient redistribution from senescing leaves to newly formed sink organs, including young leaves and developing seeds. Progress has been made concerning the genes involved and the regulatory networks controlling senescence. The resulting complex metabolome changes during senescence have not been investigated in detail yet. Therefore, we conducted a comprehensive profiling of metabolites, including pigments, lipids, sugars, amino acids, organic acids, nutrient ions, and secondary metabolites, and determined approximately 260 metabolites at distinct stages in leaves and siliques during senescence in Arabidopsis (Arabidopsis thaliana). This provided an extensive catalog of metabolites and their spatiotemporal cobehavior with progressing senescence. Comparison with silique data provides clues to source-sink relations. Furthermore, we analyzed the metabolite distribution within single leaves along the basipetal sink-source transition trajectory during senescence. Ceramides, lysolipids, aromatic amino acids, branched chain amino acids, and stress-induced amino acids accumulated, and an imbalance of asparagine/aspartate, glutamate/glutamine, and nutrient ions in the tip region of leaves was detected. Furthermore, the spatiotemporal distribution of tricarboxylic acid cycle intermediates was already changed in the presenescent leaves, and glucosinolates, raffinose, and galactinol accumulated in the base region of leaves with preceding senescence. These results are discussed in the context of current models of the metabolic shifts occurring during developmental and environmentally induced senescence. As senescence processes are correlated to crop yield, the metabolome data and the approach provided here can serve as a blueprint for the analysis of traits and conditions linking crop yield and senescence.
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Affiliation(s)
- Mutsumi Watanabe
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
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Khan NA, Cone JW, Pellikaan WF, Khan MA, Struik PC, Hendriks WH. Changes in fatty acid content and composition in silage maize during grain filling. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2011; 91:1041-1049. [PMID: 21328353 DOI: 10.1002/jsfa.4279] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 11/29/2010] [Accepted: 12/04/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND The stage of maturity at harvest has a major effect on the fatty acid (FA) content and composition of forage plants consumed by dairy cows. The present study investigated the dynamics of FA content and composition in stover (leaves and stem) and ears (cob, shank and husks) of two maize genotypes (G2 and G6) grown on sandy and clay soils and harvested at 14, 42, 56, 70 and 84 days after flowering (DAF). In addition, the FA content and composition of six maize genotypes (G1-G6) grown on the two soil types were compared at the normal harvest time of early genotypes in the Netherlands (70 DAF). RESULTS The contents of total FAs and major individual FAs in both stover and ears changed significantly (P < 0.001) during the grain-filling period (14-84 DAF). In stover the contents of C16:0, C18:2, C18:3 and total FAs declined (P < 0.001) while those of C18:0 and C18:1 increased (P < 0.001) with progressive grain filling. The rate of decline in C18:3 and total FA contents was slower during 14-56 DAF as compared with 56-84 DAF. In ears, the contents of C16:0, C18:1, C18:2 and total FAs increased up to 56 DAF and then remained more or less constant until 84 DAF. At 70 DAF the content of polyunsaturated fatty acids (PUFAs) in both stover and ears did not differ among the six genotypes. However, the average contents of C16:0, C18:3 and total FAs in stover were higher (P < 0.05) on clay soil, whereas those of C18:0 and C18:1 were higher on sandy soil. CONCLUSION The results demonstrate that the maximum PUFA content in silage maize is harvested around 56 DAF, in the present study at a T(sum) of 927 °C.d or at an ear dry matter content of 440 g kg(-1) , which is before the onset of rapid senescence. Any further delay in harvesting will cause a rapid decline in C18:3 content in maize silages.
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Affiliation(s)
- Nazir A Khan
- Animal Nutrition Group, Department of Animal Sciences, Wageningen University, PO Box 338, NL-6700 AH Wageningen, The Netherlands.
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Yang Z, Ohlrogge JB. Turnover of fatty acids during natural senescence of Arabidopsis, Brachypodium, and switchgrass and in Arabidopsis beta-oxidation mutants. PLANT PHYSIOLOGY 2009; 150:1981-9. [PMID: 19561121 PMCID: PMC2719120 DOI: 10.1104/pp.109.140491] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 06/22/2009] [Indexed: 05/17/2023]
Abstract
During leaf senescence, macromolecule breakdown occurs and nutrients are translocated to support growth of new vegetative tissues, seeds, or other storage organs. In this study, we determined the fatty acid levels and profiles in Arabidopsis (Arabidopsis thaliana), Brachypodium distachyon, and switchgrass (Panicum virgatum) leaves during natural senescence. In young leaves, fatty acids represent 4% to 5% of dry weight and approximately 10% of the chemical energy content of the leaf tissues. In all three species, fatty acid levels in leaves began to decline at the onset of leaf senescence and progressively decreased as senescence advanced, resulting in a greater than 80% decline in fatty acids on a dry weight basis. During senescence, Arabidopsis leaves lost 1.6% of fatty acids per day at a rate of 2.1 mug per leaf (0.6 mug mg(-1) dry weight). Triacylglycerol levels remained less than 1% of total lipids at all stages. In contrast to glycerolipids, aliphatic surface waxes of Arabidopsis leaves were much more stable, showing only minor reduction during senescence. We also examined three Arabidopsis mutants, acx1acx2, lacs6lacs7, and kat2, which are blocked in enzyme activities of beta-oxidation and are defective in lipid mobilization during seed germination. In each case, no major differences in the fatty acid contents of leaves were observed between these mutants and the wild type, indicating that several mutations in beta-oxidation that cause reduced breakdown of reserve oil in seeds do not substantially reduce the degradation of fatty acids during leaf senescence.
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Affiliation(s)
- Zhenle Yang
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
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Traill W, Arnoult M, Chambers S, Deaville E, Gordon M, John P, Jones P, Kliem K, Mortimer S, Tiffin J. The potential for competitive and healthy food chains of benefit to the countryside. Trends Food Sci Technol 2008. [DOI: 10.1016/j.tifs.2008.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dewhurst R, Shingfield K, Lee M, Scollan N. Increasing the concentrations of beneficial polyunsaturated fatty acids in milk produced by dairy cows in high-forage systems. Anim Feed Sci Technol 2006. [DOI: 10.1016/j.anifeedsci.2006.04.016] [Citation(s) in RCA: 269] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Givens D, Kliem KE, Gibbs RA. The role of meat as a source of n−3 polyunsaturated fatty acids in the human diet. Meat Sci 2006; 74:209-18. [DOI: 10.1016/j.meatsci.2006.04.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/05/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
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Djebali W, Zarrouk M, Brouquisse R, El Kahoui S, Limam F, Ghorbel MH, Chaïbi W. Ultrastructure and lipid alterations induced by cadmium in tomato (Lycopersicon esculentum) chloroplast membranes. PLANT BIOLOGY (STUTTGART, GERMANY) 2005; 7:358-68. [PMID: 16025408 DOI: 10.1055/s-2005-837696] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The effects of cadmium (Cd) uptake on ultrastructure and lipid composition of chloroplasts were investigated in 28-day-old tomato plants (Lycopersicon esculentum var. Ibiza F1) grown for 10 days in the presence of various concentrations of CdCl2. Different growth parameters, lipid and fatty acid composition, lipid peroxidation, and lipoxygenase activity were measured in the leaves in order to assess the involvement of this metal in the generation of oxidative stress. We first observed that the accumulation of Cd increased with external metal concentration, and was considerably higher in roots than in leaves. Cadmium induced a significant inhibition of growth in both plant organs, as well as a reduction in the chlorophyll and carotenoid contents in the leaves. Ultrastructural investigations revealed that cadmium induced disorganization in leaf structure, essentially marked by a lowered mesophyll cell size, reduced intercellular spaces, as well as severe alterations in chloroplast fine structure, which exhibits disturbed shape and dilation of thylakoid membranes. High cadmium concentrations also affect the main lipid classes, leading to strong changes in their composition and fatty acid content. Thus, the exposure of tomato plants to cadmium caused a concentration-related decrease in the fatty acid content and a shift in the composition of fatty acids, resulting in a lower degree of fatty acid unsaturation in chloroplast membranes. The level of lipid peroxides and the activity of lipoxygenase were also significantly enhanced at high Cd concentrations. These biochemical and ultrastructural changes suggest that cadmium, through its effects on membrane structure and composition, induces premature senescence of leaves.
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Affiliation(s)
- W Djebali
- Laboratoire de Physiologie Végétale, U.R. "Nutrition et Métabolisme Azotés et Protéines de Stress", Département de Biologie, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia.
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Dewhurst RJ, Scollan ND, Lee MRF, Ougham HJ, Humphreys MO. Forage breeding and management to increase the beneficial fatty acid content of ruminant products. Proc Nutr Soc 2004; 62:329-36. [PMID: 14506880 DOI: 10.1079/pns2003241] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The declining consumption of ruminant products has been partly associated with their high proportion (but not necessarily content) of saturated fatty acids. Recent studies have focused on the less prominent fact that they are also important sources of beneficial fatty acids, including n-3 fatty acids and conjugated linoleic acids. alpha-Linolenic acid (18 : 3n-3) is of particular interest because it also contributes to improved flavour of beef and lamb. Many recent studies showed large effects of special concentrates on levels of fatty acids in milk and meat. However, the 'rumen protection' treatments, needed to ensure a worthwhile level of fatty acid in products, are expensive. Herbage lipids are the cheapest and safest source of these fatty acids and so breeding to increase delivery of fatty acids from plants into ruminant products is an important long-term strategy. Plant lipids usually contain high levels of polyunsaturated fatty acids, particularly 18 : 2n-6 and 18 : 3n-3 which are the precursors of beneficial fatty acids. Whilst some plants are particularly rich in individual fatty acids (e.g. 18 : 3n-3 in linseed), there are also useful levels in grass and clover (Trifolium Spp.). Levels of fatty acids in forages in relation to species and varieties are considered, as well as management and conservation methods. Relationships between levels of fatty acids and existing traits and genetic markers are identified. The effects of forage treatments on the fatty acid content of ruminant products are reviewed. The higher levels of polyunsaturated fatty acids in milk from cows fed clover silages show that the level of fatty acids in herbage is not the only factor affecting levels of fatty acids in ruminant products. Further effort is needed to characterise susceptibility of unsaturated fatty acids to oxidative loss during field wilting and biohydrogenation losses in the rumen, and the relative importance of plant and microbial processes in these losses. The pathways of lipolysis and lipid oxidation are reviewed and other plant factors which offer potential to breed for reduced losses are considered.
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Affiliation(s)
- R J Dewhurst
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
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Abstract
Although the loss of green color in senescent leaves and ripening fruits is a spectacular natural phenomenon, research on chlorophyll breakdown has been largely neglected until recently. This review summarizes knowledge about the fate of chlorophyll in degreening tissues that has been gained during the past few years. Structures of end- and intermediary products of degradation as well as the biochemistry of the porphyrin-cleaving reaction have been elucidated. The intracellular localization of the catabolic pathway is particularly important in the regulation of chlorophyll breakdown. None of the genes encoding the related catabolic enzymes has so far been isolated, which makes chlorophyll degradation an area of opportunity for future research.
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Affiliation(s)
- Philippe Matile
- University of Zurich, Institute of Plant Biology, Zollikerstrasse 107, Zurich, CH 8008 Switzerland; e-mail: , Cell Biology Department, Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion, SY23 3EB, United Kingdom; e-mail:
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Vicentini F, Hörtensteiner S, Schellenberg M, Thomas H, Matile P. Chlorophyll breakdown in senescent leaves identification of the biochemical lesion in a stay-green genotype of Festuca pratensis Huds. THE NEW PHYTOLOGIST 1995; 129:247-252. [PMID: 33874551 DOI: 10.1111/j.1469-8137.1995.tb04294.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Chlorophyll breakdown in senescent leaves proceeds in essentially three steps: dephytylation by the action of chlorophyllase; conversion of chlorophyllide to phaeophorbide by Mg-dechelatase; and oxygenolytic cleavage of the chlorine-macrocycle by a newly discovered dioxygenase. The metabolic lesion responsible for high retention of chlorophyll during foliar senescence in a mutant genotype of meadow fescue (Festuca pratensis Huds.) was located in the third step of the breakdown pathway. Senescent leaves of both the normally yellowing reference genotype, c.v Rossa, and the non-yellowing mutant Bf993 were shown to be competent with regard to chlorophyllase and Mg-dechelatase. On the other hand, thylakoids isolated from senescent leaves of cv. Rossa were able to carry out oxygenolysis of phaeophorbide into a colourless fluorescent catabolite in vitro, whereas Bf993 thylakoids were deficient in this activity. It is concluded that the Sid locus, a mutant allele of which is responsible for the stay-green character, encodes or regulates the gene for, phaeophorbide a dioxygenase.
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Affiliation(s)
- Fabrizio Vicentini
- Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
| | - Stefan Hörtensteiner
- Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
| | - Maya Schellenberg
- Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
| | - Howard Thomas
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Dyfed, SY23 3EB, UK
| | - Philippe Matile
- Institut für Pflanzenbiologie, Universität Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
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Sahsah Y, Pham Thi AT, Roy-Macauley H, d'Arcy-Lameta A, Repellin A, Zuily-Fodil Y. Purification and characterization of a soluble lipolytic acylhydrolase from Cowpea (Vigna unguiculata L.) leaves. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1215:66-73. [PMID: 7948009 DOI: 10.1016/0005-2760(94)90092-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
With the use of [14C]monogalactosyl diacylglycerol as substrate for enzymatic test, a lipolytic acylhydrolase (EC 3.1.1.26) was purified 263-fold with a yield of 2.0% from soluble leaf extract of Vigna unguiculata L. cv. EPACE-1. The procedure involved ammonium sulfate precipitation, Q-Sepharose Fast Flow chromatography, gel filtration on Sephacryl 300 HR and chromatofocusing on Mono-P, followed by a semi-preparative electrophoresis on polyacrylamide gel. The purified enzyme had a molecular mass of about 80 kDa, as determined by gel filtration. On SDS-PAGE, it showed a single band corresponding to a molecular mass of 40 kDa. The isoelectric point of the enzyme was estimated to be 5.0-5.1 by isoelectric focusing and chromatofocusing. The Km value was 0.119 mM for monogalactosyl-diacylglycerol. The hydrolytic activity of the enzyme on different substrates was determined: the relative rates were digalactosyl-diacylglycerol > monogalactosyl-diacylglycerol > phosphatidylcholine > phosphatidylglycerol. For all substrates, the products of hydrolysis were free fatty acids. Triacylglycerols were not hydrolysed. The enzyme was activated by calcium but was not calcium-dependent. Experiments concerning the enzyme stability as affected by temperature and pH demonstrated that it was quite stable.
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Affiliation(s)
- Y Sahsah
- Laboratoire Biochimie et Physiologie de l'Adaptation Végétale, Université Paris 7 Denis Diderot, France
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Abstract
Leaf senescence is a hiphly-controlled sequence of events comprising the final stage of development. Cells remain viable during the process and new gene expression is required. There is some similarity between senescence in plants and programmed cell death in animals. In this review, different classes of senescence-related genes are defined and progress towards isolating such genes is reported. A range of internal and external factors which appear to cause leaf senescence is considered and various models for the mechanism of senescence- initiation are described. The current understanding of senescence at the wrganelle and molecular levels is presented. Finally, same ideas are mooted as to why senescence occurs and why it should be studied further. Contents Summary 419 I. Introduction 420 II. Internal factors that cause senescence 423 III. External factors that cause senescence 427 IV. What is the mechanism of senescence initiation? 428 V. Progress in the understanding of organelle senescence 431 VI. Progress in the understanding of senescence at the molecular level 434 VII. The control of senescence in animals and plants 440 VIII. Why is senescence necessary? 441 IX. Why study senescence? 441 References 442.
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Affiliation(s)
- Catherine M Smart
- Cell Biology Department, Institute of Grassland and Environment Research, Plas Gogerddan, Aberystwyth, Dyfed, SY23 3EB, Wales, UK
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Hilditch PI, Thomas H, Thomas BJ, Rogers LJ. Leaf senescence in a non-yellowing mutant of Festuca pratensis: Proteins of photosystem II. PLANTA 1989; 177:265-272. [PMID: 24212349 DOI: 10.1007/bf00392815] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/1988] [Accepted: 10/27/1988] [Indexed: 06/02/2023]
Abstract
The senescence of leaves is characterized by yellowing as chlorophyll pigments are degraded. Proteins of the chloroplasts also decline during this phase of development. There exists a non-yellowing mutant genotype of Festuca pratensis Huds. which does not suffer a loss of chlorophyll during senescence. The fate of chloroplast membrane proteins was studied in mutant and wild-type plants by immune blotting and immuno-electron microscopy. Intrinsic proteins of photosystem II, exemplified by the light-harvesting chlorophyll a/b-binding protein (LHCP-2) and D1, were shown to be unusually stable in the mutant during senescence, whereas the extrinsic 33-kilodalton protein of the oxygen-evolving complex was equally lable in both genotypes. An ultrastructural study revealed that while the intrinsic proteins remained in the internal membranes of the chloroplasts, they ceased to display the heterogenous lateral distribution within the lamellae which was characteristic of nonsenescent chloroplasts. These observations are discussed in the light of possible mechanisms of protein turnover in chloroplasts.
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Affiliation(s)
- P I Hilditch
- Plant and Cell Biology Department, Institute for Grassland and Animal Production, Welsh Plant Breeding Station, Plas Gogerddan, SY23 3EB, Aberystwyth, Dyfed, UK
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Gut H, Matile P. Apparent induction of key enzymes of the glyoxylic acid cycle in senescent barley leaves. PLANTA 1988; 176:548-550. [PMID: 24220952 DOI: 10.1007/bf00397663] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/1988] [Accepted: 06/28/1988] [Indexed: 06/02/2023]
Abstract
The activities of two key enzymes of the glyoxylic-acid cycle, isocitrate lyase and malate synthase, can barely be detected in mature, presenescent primary leaves of barley (Hordeum vulgare L.) but are apparently induced in senescent leaf tissue. Upon incubation of leaf segments in permanent darkness, the activities appear and increase dramatically up to the sixth day and thereafter decline. The glyoxylic-acid cycle may thus be functional during foliar senescence. The main period of galactolipid loss is characterized by RQ values as low as 0.63, indicating that long-chain fatty acids produced from thylakoidal acyl-lipids may be utilized for gluconeogenesis involving corresponding glyoxisomal metabolic pathways. Foliar senescence may be characterized by a peroxisomeglyoxysome transition analogous to the glyoxisome-peroxisome transition in greening cotyledons of fat-storing seeds.
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Affiliation(s)
- H Gut
- Department of Plant Biology, University of Zürich, Zollikerstrasse 107, CH-8008, Zürich, Switzerland
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Thomas H. Sid: a Mendelian locus controlling thylakoid membrane disassembly in senescing leaves of Festuca pratensis. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1987; 73:551-555. [PMID: 24241112 DOI: 10.1007/bf00289193] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/1986] [Accepted: 10/26/1986] [Indexed: 06/02/2023]
Abstract
A spontaneous mutation arising in Festuca pratensis has the effect of stabilizing the pigmentproteolipid complexes of thylakoid membranes so that leaf tissue does not turn yellow during senescence. Inheritance of the non-yellowing character was analysed in crosses between the wild-type cultivar Rossa and a mutant line Bf 993. Electrophoretic variants of cytoplasmic phosphoglucoisomerase coded by alleles of the nuclear gene Pgi-2 were used to identify hybrids during intercrossing. About 96% of the F1 progeny were heterozygous and all were phenotypically yellowing. In the F2 generation yellow ∶ green segregated in a ratio of 2.14∶1, not significantly different from 3∶1. In the backcross between F1 and Bf 993 the ratio was 1∶1 yellow ∶ green. There was no indication of linkage to Pgi-2. Senescence of detached Bf 993 and Rossa leaves was compared with that of the F1 hybrid. The hybrid behaved in an essentially identical fashion to the wildtype parent, and in marked contrast to the mutant, in all aspects of the senescence syndrome investigated, including loss of chlorophyll, carotenoids and the light-harvesting chlorophyll-protein of thylakoid membranes, and elevation of the particulate protein ∶ chlorophyll ratio in the terminal stages. It is concluded that there exists in Festuca pratensis a nuclear gene, designated Sid (senescence-induced degradation) which regulates turnover of hydrophobic components of photosynthetic membranes in ageing leaf tissue and which occurs in at least two allelic forms, y (yellow) dominant over g (green).
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Affiliation(s)
- H Thomas
- Plants and Soils Division, Welsh Plant Breeding Station, Plas Gogerddan, SY23 3EB, Aberystwyth, Dyfed, UK
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Hilditch P, Thomas H, Rogers L. Leaf senescence in a non-yellowing mutant of Festuca pratensis: Photosynthesis and photosynthetic electron transport. PLANTA 1986; 167:146-151. [PMID: 24241745 DOI: 10.1007/bf00446382] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/1985] [Accepted: 10/15/1985] [Indexed: 06/02/2023]
Abstract
The photosynthetic capacity of detached leaves of a non-yellowing mutant of Festuca pratensis Huds. declined during senescence at a similar rate to that in a normal cultivar. Respiratory oxygen uptake in the dark continued at similar rates in both genotypes during several days of senescence. In chloroplasts isolated from leaves at intervals after excision, the rate of photosystem I (PS I)-mediated methyl viologen reduction using reduced N,N,N',N'-tetramethyl-p-phenylene diamine as electron donor also declined in both genotypes, possibly due to loss of integrity of the photosynthetic apparatus in the cytochrome f-plastocyanin region. There was a similar fall in PS II electron transport using water as electron donor and measured at the rate of reduction of 2,6-dichlorophenolindophenol. Partial restoration of this activity by the addition of diphenyl carbazide was evidence for lability of the oxygen-evolving complex during senescence. An accentuated difference between mutant and normal material in this case indicated that the mutant retains a greater number of functional PS II centres. Changes in the light-saturation characteristics of the two photosystems have been discussed in relation to the organization of the photosynthetic membranes during senescence.
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Affiliation(s)
- P Hilditch
- Plant Biochemistry Department, Welsh Plant Breeding Station, Plas Gogerddan, SY23 3EB, Aberystwyth
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Thomas H, Lüthy B, Matile P. Leaf senescence in a non-yellowing mutant of Festuca pratensis Huds. : Oxidative chlorophyll bleaching by thylakoid membranes during senescence. PLANTA 1985; 164:400-405. [PMID: 24249611 DOI: 10.1007/bf00402953] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/1984] [Accepted: 11/20/1984] [Indexed: 06/02/2023]
Abstract
A study was made of linolenic acid-dependent oxidative chlorophyll bleaching (CHLOX) by thylakoid membranes from senescing leaf tissue of a normal cultivar (cv. Rossa) and a non-yellowing mutant genotype (Bf 993) of Festuca pratensis Huds. To overcome the problem of variation in levels of endogenous chlorophyll substrate in membranes from different sources, light-harvesting complex (LHC) was used to supplement thylakoid pigment. It was shown that CHLOX is associated with both Photosystem I and LHC-rich thylakoid subfractions but that purified LHC has negligible associated CHLOX activity and stimulates the rate of bleaching by isolated entire chloroplast membranes. Non-senescent tissue of Bf 993 and Rossa had essentially identical thylakoid CHLOX levels, which subsequently declined during senescence in darkness. The half-life of CHLOX from the mutant was three times greater than that of the normal genotype. In both cultivars, the amount of CHLOX assayed in thylakoids isolated at different times during senescence was more than adequate to support the corresponding in-vivo rate of pigment degradation as calculated from the half-life for chlorophyll. It was concluded that the non-yellowing mutation is not expressed through a lack of CHLOX activity. The role of linolenic acid metabolism in the regulation of thylakoid structure and function during senescence, and as a likely site of the non-yellowing lesion, are discussed.
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Affiliation(s)
- H Thomas
- Welsh Plant Breeding Station, Plas Gogerddan, SY23 3EB, Aberystwyth, Dyfed, UK
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Lüthy B, Martinoia E, Matile P, Thomas H. Thylakoid-associated «Chlorophyll Oxidase»: Distinction from Lipoxygenase. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0044-328x(84)80098-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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