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Pérez-Llorca M, Munné-Bosch S. Aging, stress, and senescence in plants: what can biological diversity teach us? GeroScience 2021; 43:167-180. [PMID: 33590435 DOI: 10.1007/s11357-021-00336-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/03/2021] [Indexed: 11/25/2022] Open
Abstract
Aging, stress, and senescence in plants are interconnected processes that determine longevity. We focus here on compiling and discussing our current knowledge on the mechanisms of development that long-lived perennial plants have evolved to prevent and delay senescence. Clonal and nonclonal perennial herbs of various life forms and longevities will be particularly considered to illustrate what biological diversity can teach us about aging as a universal phenomenon. Source-sink relations and redox signaling will also be discussed as examples of regulatory mechanisms of senescence at the organ level. Whether or not effective mechanisms that biological diversity has evolved to completely prevent the wear and tear of aging will be applicable to human aging in the near future ultimately depends on ethical aspects.
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Affiliation(s)
- Marina Pérez-Llorca
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain.,Institute of Research in Biodiversity (IRBio), University of Barcelona, Barcelona, Spain
| | - Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain. .,Institute of Research in Biodiversity (IRBio), University of Barcelona, Barcelona, Spain.
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2
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Jan S, Abbas N, Ashraf M, Ahmad P. Roles of potential plant hormones and transcription factors in controlling leaf senescence and drought tolerance. PROTOPLASMA 2019; 256:313-329. [PMID: 30311054 DOI: 10.1007/s00709-018-1310-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
Plant leaves offer an exclusive windowpane to uncover the changes in organs, tissues, and cells as they advance towards the process of senescence and death. Drought-induced leaf senescence is an intricate process with remarkably coordinated phases of onset, progression, and completion implicated in an extensive reprogramming of gene expression. Advancing leaf senescence remobilizes nutrients to younger leaves thereby contributing to plant fitness. However, numerous mysteries remain unraveled concerning leaf senescence. We are not still able to correlate leaf senescence and drought stress to endogenous and exogenous environments. Furthermore, we need to decipher how molecular mechanisms of the leaf senescence and levels of drought tolerance are advanced and how is the involvement of SAGs in drought tolerance and plant fitness. This review provides the perspicacity indispensable for facilitating our coordinated point of view pertaining to leaf senescence together with inferences on progression of whole plant aging. The main segments discussed in the review include coordination between hormonal signaling, leaf senescence, drought tolerance, and crosstalk between hormones in leaf senescence regulation.
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Affiliation(s)
- Sumira Jan
- ICAR- Central Institute of Temperate Horticulture, Rangreth, Air Field, Srinagar, Jammu and Kashmir, India
| | - Nazia Abbas
- Indian Institute of Integrative Medicine, Sanatnagar, Srinagar, Jammu and Kashmir, India
| | | | - Parvaiz Ahmad
- Department of Botany and Microbiology, Faculty of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
- Department of Botany, S.P. College, Srinagar, Jammu and Kashmir, 190001, India.
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3
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Fan K, Zhang Q, Liu M, Ma L, Shi Y, Ruan J. Metabolomic and transcriptional analyses reveal the mechanism of C, N allocation from source leaf to flower in tea plant (Camellia sinensis. L). JOURNAL OF PLANT PHYSIOLOGY 2019; 232:200-208. [PMID: 30537607 DOI: 10.1016/j.jplph.2018.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/05/2018] [Accepted: 11/05/2018] [Indexed: 05/08/2023]
Abstract
Tea flowering in late autumn competes for a large amount of nitrogen and carbohydrates, potentially undermines the storage of these resources in vegetative organs, and negatively influences the subsequent spring tea yield and quality. The mechanism underlying the re-allocation N and carbohydrate from source leaf to flower in tea plant has not been clearly understood. In this study, 15N allocation, changes in metabolomics, and gene expression in flower buds, flowers, and adjacent leaves were characterized. Total N content of the adjacent leaves significantly decreased during flowering while such a decrease could be reversed by flower bud removal. Foliar-applied 15N in the adjacent leaves markedly decreased and was readily allocated to flowers. Metabolomic analysis revealed that most sugars and benzoic acid increased by more than two-fold whereas theanine, Gln, Arg, Asp, and Asn decreased when flower buds fully opened to become flowers. In this process, Gly, Pro, and cellobiose in the adjacent leaves increased considerably whereas sucrose, galactose, benzoic acid, and many fatty acids decreased. Removal of flower buds reversed or alleviated the above decreases and led to an increase of Asn in the leaves. The expression of genes associated with autophagy (ATG5, ATG9, ATG12, ATG18), sucrose transporters (SUT1, SUT2, SUT4), amino acids permease (AAP6, AAP7, AAP8), glutamine synthetase (GS1;1, GS1;2, GS1;3), and asparagine synthetase (ASN1, ASN2) was significantly up-regulated in leaves during the flowering process and was strongly modulated by the removal of flower buds. The overall results demonstrated that leaves are the ready source providing N and carbohydrates in flowering and a series of genes related to autophagy, protein degradation, turn-over of amino acids, and phloem loading for transport are involved.
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Affiliation(s)
- Kai Fan
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China
| | - Qunfeng Zhang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China
| | - Meiya Liu
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China
| | - Lifeng Ma
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China
| | - Yuanzhi Shi
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China
| | - Jianyun Ruan
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 31008, China.
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4
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Cao VD, Riu KZ, Boo KH. Biosynthesis and accumulation of 20-hydroxyecdysone in individual male and female spinach plants during the reproductive stage. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 129:394-399. [PMID: 29945075 DOI: 10.1016/j.plaphy.2018.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 05/23/2023]
Abstract
The steroid 20-hydroxyecdysone (20E) is a major component of phytoecdysteroid in plants and may play a defensive role against insect pests in higher plants. In spinach, the biosynthesis and accumulation of 20E have been investigated during the vegetative stage; however, these processes have not been clearly studied during the reproductive stage, particularly in male and female individuals. In this study, we analyzed the level and distribution of 20E in individual male and female spinach plants during the reproductive stage via high performance liquid chromatography (HPLC). We found that 20E biosynthesis and accumulation were markedly different between male and female spinach during the late flowering stage. Compared with the male plant, biosynthesis of 20E in the leaves was more active and its accumulation in the floral parts was higher in female plants during the late flowering stage. These results indicate that the female reproductive organs at least in PE-positive plants could be effectively protected against harmful insects via active biosynthesis and accumulation of PE during the late flowering stage to protect floral parts from harmful insects for seed formation and store the available 20E in seeds for the next generation.
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Affiliation(s)
- Viet Dang Cao
- Department of Biotechnology, College of Applied Life Science (SARI), Jeju National University, Jeju, 63243, Republic of Korea; Subtropical/Tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea
| | - Key-Zung Riu
- Department of Biotechnology, College of Applied Life Science (SARI), Jeju National University, Jeju, 63243, Republic of Korea; Subtropical/Tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea
| | - Kyung-Hwan Boo
- Department of Biotechnology, College of Applied Life Science (SARI), Jeju National University, Jeju, 63243, Republic of Korea; Subtropical/Tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea.
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Borghi M, Fernie AR. Floral Metabolism of Sugars and Amino Acids: Implications for Pollinators' Preferences and Seed and Fruit Set. PLANT PHYSIOLOGY 2017; 175:1510-1524. [PMID: 28986424 PMCID: PMC5717749 DOI: 10.1104/pp.17.01164] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/04/2017] [Indexed: 05/10/2023]
Abstract
New discoveries open up future directions in the study of the primary metabolism of flowers.
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Affiliation(s)
- Monica Borghi
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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Abdelrahman M, El-Sayed M, Jogaiah S, Burritt DJ, Tran LSP. The "STAY-GREEN" trait and phytohormone signaling networks in plants under heat stress. PLANT CELL REPORTS 2017; 36:1009-1025. [PMID: 28484792 DOI: 10.1007/s00299-017-2119-y] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 02/07/2017] [Indexed: 05/22/2023]
Abstract
The increasing demand for food and the heavy yield losses in primary crops due to global warming mean that there is an urgent need to improve food security. Therefore, understanding how plants respond to heat stress and its consequences, such as drought and increased soil salinity, has received much attention in plant science community. Plants exhibit stress tolerance, escape or avoidance via adaptation and acclimatization mechanisms. These mechanisms rely on a high degree of plasticity in their cellular metabolism, in which phytohormones play an important role. "STAY-GREEN" is a crucial trait for genetic improvement of several crops, which allows plants to keep their leaves on the active photosynthetic level under stress conditions. Understanding the physiological and molecular mechanisms concomitant with "STAY-GREEN" trait or delayed leaf senescence, as well as those regulating photosynthetic capability of plants under heat stress, with a certain focus on the hormonal pathways, may be a key to break the plateau of productivity associated with adaptation to high temperature. This review will discuss the recent findings that advance our understanding of the mechanisms controlling leaf senescence and hormone signaling cascades under heat stress.
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Affiliation(s)
- Mostafa Abdelrahman
- Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Botany Department Faculty of Science, Aswan University, Aswan, 81528, Egypt
| | - Magdi El-Sayed
- Botany Department Faculty of Science, Aswan University, Aswan, 81528, Egypt
| | - Sudisha Jogaiah
- Plant Healthcare and Diagnostic Center, PG Department of Biotechnology and Microbiology, Karnatak University, Dharwad, Karnataka, 580 003, India
| | - David J Burritt
- Department of Botany, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Lam-Son Phan Tran
- Plant Abiotic Stress Research Group & Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, 70000, Vietnam.
- Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro-cho, Tsurumi, Yokohama, 230-0045, Japan.
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Martínková J, Šmilauer P, Mihulka S, Latzel V, Klimešová J. The effect of injury on whole-plant senescence: an experiment with two root-sprouting Barbarea species. ANNALS OF BOTANY 2016; 117:667-79. [PMID: 26975314 PMCID: PMC4817502 DOI: 10.1093/aob/mcw010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/05/2015] [Accepted: 12/13/2015] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Senescence is the process of losing fitness when growing old, and is shaped by the trade-off between maintenance and reproduction that makes reproduction more unsure and maintenance more costly with age. In repeatedly reproducing plants, reductions in growth and fertility are signs of senescence. Disturbance, however, provides an opportunity to reset the ageing clock and consequently potentially ameliorate senescence. METHODS To test the effects of disturbance on traits closely related to fitness and thus to senescence, a long-term garden experiment was established with two short-lived perennial congeners,Barbarea vulgaris and Barbarea stricta, that differ in their ability to resprout after injury. In the experiment, five damage treatments were applied to plants in four different phenophases. KEY RESULTS It was found that damage to the plant body significantly prolonged life span in B. vulgaris but decreased whole-life seed production in both species. High concentration of seed production in one growing season characterized short life spans. Both more severe damage and a more advanced phenological phase at the time of damage caused reproduction to be spread over more than one growing season and equalized per-season seed production. In terms of seed quality, average weight of a single seed decreased and seed germination rate increased with age regardless of damage. CONCLUSIONS Although disturbance is able to reset the ageing clock of plants, it is so harmful to plant fitness that resprouting serves, at best, only to alleviate slightly the signs of senescence. Thus, in terms of whole-life seed production, injured plants were not more successful than uninjured ones in the two studied species. Indeed, in these species, injury only slightly postponed or decelerated senescence and did not cause effective rejuvenation.
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Affiliation(s)
- Jana Martínková
- Institute of Botany, The Czech Academy of Sciences, Dukelská 135, 379 82 Třeboň, Czech Republic,
| | - Petr Šmilauer
- University of South Bohemia, Faculty of Science, Branišovská 1760, 370 05 České Budějovice, Czech Republic and
| | - Stanislav Mihulka
- University of South Bohemia, Faculty of Science, Branišovská 1760, 370 05 České Budějovice, Czech Republic and
| | - Vít Latzel
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
| | - Jitka Klimešová
- Institute of Botany, The Czech Academy of Sciences, Dukelská 135, 379 82 Třeboň, Czech Republic
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Zhang Y, Zhang D, Yu H, Lin B, Fu Y, Hua S. Floral Initiation in Response to Planting Date Reveals the Key Role of Floral Meristem Differentiation Prior to Budding in Canola (Brassica napus L.). FRONTIERS IN PLANT SCIENCE 2016; 7:1369. [PMID: 27683582 PMCID: PMC5021690 DOI: 10.3389/fpls.2016.01369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/29/2016] [Indexed: 05/16/2023]
Abstract
In Brassica napus, floral development is a decisive factor in silique formation, and it is influenced by many cultivation practices including planting date. However, the effect of planting date on floral initiation in canola is poorly understood at present. A field experiment was conducted using a split plot design, in which three planting dates (early, 15 September, middle, 1 October, and late, 15 October) served as main plot and five varieties differing in maturity (1358, J22, Zhongshuang 11, Zheshuang 8, and Zheyou 50) employed as subplot. The purpose of this study was to shed light on the process of floral meristem (FM) differentiation, the influence of planting date on growth period (GP) and floral initiation, and silique formation. The main stages of FM developments can be divided into four stages: first, the transition from shoot apical meristem to FM; second, flower initiation; third, gynoecium and androecium differentiation; and fourth, bud formation. Our results showed that all genotypes had increased GPs from sowing to FM differentiation as planting date was delayed while the GPs from FM differentiation to budding varied year by year except the very early variety, 1358. Based on the number of flowers present at the different reproductive stages, the flowers produced from FM differentiation to budding closely approximated the final silique even though the FM differentiated continuously after budding and peaked generally at the middle flowering stage. The ratio of siliques to maximum flower number ranged from 48 to 80%. These results suggest that (1) the period from FM differentiation to budding is vital for effective flower and silique formation although there was no significant correlation between the length of the period and effective flowers and siliques, and (2) the increased number of flowers from budding were generally ineffective. Therefore, maximizing flower numbers prior to budding will improve silique numbers, and reducing FM degeneration should also increase final silique formation. From the results of our study, we offer guidelines for planting canola varieties that differ in maturity in order to maximize effective flower numbers.
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Affiliation(s)
| | | | | | | | | | - Shuijin Hua
- *Correspondence: Shuijin Hua, Dongqing Zhang,
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9
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Kohl S, Hollmann J, Erban A, Kopka J, Riewe D, Weschke W, Weber H. Metabolic and transcriptional transitions in barley glumes reveal a role as transitory resource buffers during endosperm filling. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1397-411. [PMID: 25617470 PMCID: PMC4339599 DOI: 10.1093/jxb/eru492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
During grain filling in barley (Hordeum vulgare L. cv. Barke) reserves are remobilized from vegetative organs. Glumes represent the vegetative tissues closest to grains, senesce late, and are involved in the conversion of assimilates. To analyse glume development and metabolism related to grain filling, parallel transcript and metabolite profiling in glumes and endosperm were performed, showing that glume metabolism and development adjusts to changing grain demands, reflected by specific signatures of metabolite and transcript abundances. Before high endosperm sink strength is established by storage product accumulation, glumes form early, intermediary sink organs, shifting then to remobilizing and exporting source organs. Metabolic and transcriptional transitions occur at two phases: first, at the onset of endosperm filling, as a consequence of endosperm sink activity and assimilate depletion in endosperm and vascular tissues; second, at late grain filling, by developmental ageing and senescence. Regulation of and transition between phases are probably governed by specific NAC and WRKY transcription factors, and both abscisic and jasmonic acid, and are accompanied by changed expression of specific nitrogen transporters. Expression and metabolite profiling suggest glume-specific mechanisms of assimilate conversion and translocation. In summary, grain filling and endosperm sink strength coordinate phase changes in glumes via metabolic, hormonal, and transcriptional control. This study provides a comprehensive view of barley glume development and metabolism, and identifies candidate genes and associated pathways, potentially important for breeding improved grain traits.
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Affiliation(s)
- Stefan Kohl
- Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Gatersleben, Germany
| | - Julien Hollmann
- Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
| | - Alexander Erban
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Joachim Kopka
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - David Riewe
- Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Gatersleben, Germany
| | - Winfriede Weschke
- Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Gatersleben, Germany
| | - Hans Weber
- Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Gatersleben, Germany
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10
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Goyal RK, Hancock REW, Mattoo AK, Misra S. Expression of an engineered heterologous antimicrobial peptide in potato alters plant development and mitigates normal abiotic and biotic responses. PLoS One 2013; 8:e77505. [PMID: 24147012 PMCID: PMC3797780 DOI: 10.1371/journal.pone.0077505] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 09/04/2013] [Indexed: 12/26/2022] Open
Abstract
Antimicrobial cationic peptides (AMPs) are ubiquitous small proteins used by living cells to defend against a wide spectrum of pathogens. Their amphipathic property helps their interaction with negatively charged cellular membrane of the pathogen causing cell lysis and death. AMPs also modulate signaling pathway(s) and cellular processes in animal models; however, little is known of cellular processes other than the pathogen-lysis phenomenon modulated by AMPs in plants. An engineered heterologous AMP, msrA3, expressed in potato was previously shown to cause resistance of the transgenic plants against selected fungal and bacterial pathogens. These lines together with the wild type were studied for growth habits, and for inducible defense responses during challenge with biotic (necrotroph Fusarium solani) and abiotic stressors (dark-induced senescence, wounding and temperature stress). msrA3-expression not only conferred protection against F. solani but also delayed development of floral buds and prolonged vegetative phase. Analysis of select gene transcript profiles showed that the transgenic potato plants were suppressed in the hypersensitive (HR) and reactive oxygen species (ROS) responses to both biotic and abiotic stressors. Also, the transgenic leaves accumulated lesser amounts of the defense hormone jasmonic acid upon wounding with only a slight change in salicylic acid as compared to the wild type. Thus, normal host defense responses to the pathogen and abiotic stressors were mitigated by msrA3 expression suggesting MSRA3 regulates a common step(s) of these response pathways. The stemming of the pathogen growth and mitigating stress response pathways likely contributes to resource reallocation for higher tuber yield.
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Affiliation(s)
- Ravinder K. Goyal
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Autar K. Mattoo
- The Henry A. Wallace Beltsville Agricultural Research Center, United States Department of Agriculture, Agricultural Research Service, Sustainable Agricultural Systems Laboratory, Beltsville, Maryland, United States of America
| | - Santosh Misra
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
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Jibran R, A Hunter D, P Dijkwel P. Hormonal regulation of leaf senescence through integration of developmental and stress signals. PLANT MOLECULAR BIOLOGY 2013; 82:547-61. [PMID: 23504405 DOI: 10.1007/s11103-013-0043-2] [Citation(s) in RCA: 181] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 03/07/2013] [Indexed: 05/18/2023]
Abstract
Leaf senescence is a genetically controlled dismantling programme that enables plants to efficiently remobilise nutrients to new growing sinks. It involves substantial metabolic reprogramming whose timing is affected by developmental and environmental signals. Plant hormones have long been known to affect the timing of leaf senescence, but they also affect plant development and stress responses. It has therefore been difficult to tease apart how the different hormones regulate the onset and progression of leaf senescence, i.e., whether they directly affect leaf senescence or affect it indirectly by altering the developmental programme or by altering plants' response to stress. Here we review research on hormonal regulation of leaf senescence and propose that hormones affect senescence through differential responses to developmental and environmental signals. We suggest that leaf senescence strictly depends on developmental changes, after which senescence can be induced, depending on the type of hormonal and environmental cues.
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Affiliation(s)
- Rubina Jibran
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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12
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Thomas H. Senescence, ageing and death of the whole plant. THE NEW PHYTOLOGIST 2013; 197:696-711. [PMID: 23176101 DOI: 10.1111/nph.12047] [Citation(s) in RCA: 242] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 10/15/2012] [Indexed: 05/18/2023]
Abstract
UNLABELLED 696 I. 697 II. 697 III. 699 IV. 700 V. 703 VI. 704 VII. 707 708 References 708 SUMMARY This review considers the relationship between the lifespan of an individual plant and the longevity of its component cells, tissues and organs. It begins by defining the terms senescence, growth, development, turnover, ageing, death and program. Genetic and epigenetic mechanisms regulating phase change from juvenility to maturity influence directly the capacity for responding to senescence signals and factors determining reproduction-related patterns of deteriorative ageing and death. Senescence is responsive to communication between sources and sinks in which sugar signalling and hormonal regulation play central roles. Monocarpy and polycarpy represent contrasting outcomes of the balance between the determinacy of apical meristems and source-sink cross-talk. Even extremely long-lived perennials sustain a high degree of meristem integrity. Factors associated with deteriorative ageing in animals, such as somatic mutation, telomere attrition and the costs of repair and maintenance, do not seem to be particularly significant for plant lifespan, but autophagy-related regulatory networks integrated with nutrient signalling may have a part to play. Size is an important influence on physiological function and fitness of old trees. Self-control of modular structure allows trees to sustain viability over prolonged lifespans. Different turnover patterns of structural modules can account for the range of plant life histories and longevities.
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Affiliation(s)
- Howard Thomas
- IBERS, Aberystwyth University, Edward Llwyd Building, Aberystwyth, Ceredigion, SY23 3DA, UK
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13
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Overexpression of the maize Corngrass1 microRNA prevents flowering, improves digestibility, and increases starch content of switchgrass. Proc Natl Acad Sci U S A 2011; 108:17550-5. [PMID: 21987797 DOI: 10.1073/pnas.1113971108] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biofuels developed from biomass crops have the potential to supply a significant portion of our transportation fuel needs. To achieve this potential, however, it will be necessary to develop improved plant germplasm specifically tailored to serve as energy crops. Liquid transportation fuel can be created from the sugars locked inside plant cell walls. Unfortunately, these sugars are inherently resistant to hydrolytic release because they are contained in polysaccharides embedded in lignin. Overcoming this obstacle is a major objective toward developing sustainable bioenergy crop plants. The maize Corngrass1 (Cg1) gene encodes a microRNA that promotes juvenile cell wall identities and morphology. To test the hypothesis that juvenile biomass has superior qualities as a potential biofuel feedstock, the Cg1 gene was transferred into several other plants, including the bioenergy crop Panicum virgatum (switchgrass). Such plants were found to have up to 250% more starch, resulting in higher glucose release from saccharification assays with or without biomass pretreatment. In addition, a complete inhibition of flowering was observed in both greenhouse and field grown plants. These results point to the potential utility of this approach, both for the domestication of new biofuel crops, and for the limitation of transgene flow into native plant species.
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