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Asim M, Zhang Y, Sun Y, Guo M, Khan R, Wang XL, Hussain Q, Shi Y. Leaf senescence attributes: the novel and emerging role of sugars as signaling molecules and the overlap of sugars and hormones signaling nodes. Crit Rev Biotechnol 2023; 43:1092-1110. [PMID: 35968918 DOI: 10.1080/07388551.2022.2094215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/08/2022] [Indexed: 11/03/2022]
Abstract
Sugars are the primary products of photosynthesis and play multiple roles in plants. Although sugars are usually considered to be the building blocks of energy storage and carbon transport molecules, they have also gradually come to be acknowledged as signaling molecules that can initiate senescence. Senescence is an active and essential process that occurs at the last developmental stage and corresponds to programmed degradation of: cells, tissues, organs, and entire organisms. It is a complex process involving: numerous biochemical changes, transporters, genes, and transcription factors. The process is controlled by multiple developmental signals, among which sugar signals are considered to play a vital role; however, the regulatory pathways involved are not fully understood. The dynamic mechanistic framework of sugar accumulation has an inconsistent effect on senescence through the sugar signaling pathway. Key metabolizing enzymes produce different sugar signals in response to the onset of senescence. Diverse sugar signal transduction pathways and a variety of sugar sensors are involved in controlling leaf senescence. This review highlights the processes underlying initiation of sugar signaling and crosstalk between sugars and hormones signal transduction pathways affecting leaf senescence. This summary of the state of current knowledge across different plants aids in filling knowledge gaps and raises key questions that remain to be answered with respect to regulation of leaf senescence by sugar signaling pathways.
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Affiliation(s)
- Muhammad Asim
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
| | - Yan Zhang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, China
| | - Yanguo Sun
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
| | - Mei Guo
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, China
| | - Rayyan Khan
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
| | - Xiao Lin Wang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
| | - Quaid Hussain
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, China
| | - Yi Shi
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Tobacco Biology and Processing, Ministry of Agriculture and Rural Affairs, Qingdao, China
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2
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Sun X, Liu L, Cheng L. Photo- and Tetrazine-Responsive Modulation of trans-Zeatin. J Org Chem 2023. [PMID: 36763518 DOI: 10.1021/acs.joc.2c02601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Photoirradiation and small organic molecule triggering of appropriately designed caged hormones enable the control and manipulation of the corresponding biological processes with high spatial and temporal resolution. Caged trans-zeatin substituted with nitrobenzene carbonates as photoremovable protecting groups and trans-cyclooctene as the tetrazine-responsive motif have been synthesized. A smooth release of the trapped trans-zeatin molecule has been achieved, permitting targeted perturbation of biological processes, including degradation, glucosylation, and recognition by appropriate enzymes.
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Affiliation(s)
- Xin Sun
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Cheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Khuman A, Kumar V, Chaudhary B. Evolutionary expansion and expression dynamics of cytokinin-catabolizing CKX gene family in the modern amphidiploid mustard ( Brassica sp.). 3 Biotech 2022; 12:233. [PMID: 35996674 PMCID: PMC9391556 DOI: 10.1007/s13205-022-03294-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 08/02/2022] [Indexed: 11/01/2022] Open
Abstract
Plant cytokinins (CKs) promote development and physiological processes, drought tolerance, root architecture, and ultimately crop productivity. Biologically active CKs (iP, tZ, and cZ) are precisely maintained in the vegetative and floral tissues through their irreversible degradation by developmentally regulated CK-catabolizing cytokinin oxidase/dehydrogenase (CKX) enzyme. A meta-analysis of CKX proteins was performed through an exhaustive exploration of multiple genome databases of cyanobacteria, bryophyte, monocot and eudicot plants to reveal the intricate evolutionary profiles of CKX enzymes specific to the family Brassicaceae. At least 175 unique paralogous/orthologous CKX sequences were successfully retrieved and phylogenetically clustered into distinct groups. Observations of structural divergences among paralogous sequences compared to their orthologs indicated that the progenitor CKX sequence had been subjected to massive structural modifications, possibly as a result of the evolutionary split between monocots and eudicots. An analysis of dN/dS comparisons of orthologous genes revealed that segmental CKX gene duplications have evolved primarily under purifying selection. Further, 24 CKX genes with conserved signature domain were identified in the amphidiploid Brassica juncea genome (AABB; 2n = 36). Genetic evolution of paralogous and orthologous genes was largely responsible for the expansion of CKX homoeologs in the amphidiploid Brassica genomes. Also, comparative analyses of 1.5 kb-long upstream regulatory regions of BjCKX genes identified various development- and stress-responsive elements. Spatial and temporal expression profiles of CKX genes were primarily attributed to their structural diversity observed in the 5'-regulatory regions along with species evolution. This data suggested that CKX duplicate genes had partitioned their spatial expression (= function) during evolution. These findings illustrated the evolutionary importance of CKX genes during plant development, and also suggested their deployment for future crop improvement programs. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-022-03294-0.
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Affiliation(s)
| | - Vijay Kumar
- Department of Botany, Shivaji College, University of Delhi, New Delhi, 110027 India
| | - Bhupendra Chaudhary
- School of Biotechnology, Gautam Buddha University, Greater Noida, 201312 India
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Aremu AO, Fawole OA, Makunga NP, Masondo NA, Moyo M, Buthelezi NMD, Amoo SO, Spíchal L, Doležal K. Applications of Cytokinins in Horticultural Fruit Crops: Trends and Future Prospects. Biomolecules 2020; 10:biom10091222. [PMID: 32842660 PMCID: PMC7563339 DOI: 10.3390/biom10091222] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 12/15/2022] Open
Abstract
Cytokinins (CKs) are a chemically diverse class of plant growth regulators, exhibiting wide-ranging actions on plant growth and development, hence their exploitation in agriculture for crop improvement and management. Their coordinated regulatory effects and cross-talk interactions with other phytohormones and signaling networks are highly sophisticated, eliciting and controlling varied biological processes at the cellular to organismal levels. In this review, we briefly introduce the mode of action and general molecular biological effects of naturally occurring CKs before highlighting the great variability in the response of fruit crops to CK-based innovations. We present a comprehensive compilation of research linked to the application of CKs in non-model crop species in different phases of fruit production and management. By doing so, it is clear that the effects of CKs on fruit set, development, maturation, and ripening are not necessarily generic, even for cultivars within the same species, illustrating the magnitude of yet unknown intricate biochemical and genetic mechanisms regulating these processes in different fruit crops. Current approaches using genomic-to-metabolomic analysis are providing new insights into the in planta mechanisms of CKs, pinpointing the underlying CK-derived actions that may serve as potential targets for improving crop-specific traits and the development of new solutions for the preharvest and postharvest management of fruit crops. Where information is available, CK molecular biology is discussed in the context of its present and future implications in the applications of CKs to fruits of horticultural significance.
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Affiliation(s)
- Adeyemi O. Aremu
- Indigenous Knowledge Systems Centre, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2745, South Africa;
- Food Security and Safety Niche Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2745, South Africa
- Correspondence: (A.O.A.); (O.A.F.); (N.P.M.); Tel.: +27-18-389-2573 (A.O.A.); +27-11-559-7237 (O.A.F.); +27-21-808-3061 (N.P.M.)
| | - Olaniyi A. Fawole
- Postharvest Research Laboratory, Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, P.O. Box 524, Auckland Park 2006, South Africa;
- Correspondence: (A.O.A.); (O.A.F.); (N.P.M.); Tel.: +27-18-389-2573 (A.O.A.); +27-11-559-7237 (O.A.F.); +27-21-808-3061 (N.P.M.)
| | - Nokwanda P. Makunga
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa;
- Correspondence: (A.O.A.); (O.A.F.); (N.P.M.); Tel.: +27-18-389-2573 (A.O.A.); +27-11-559-7237 (O.A.F.); +27-21-808-3061 (N.P.M.)
| | - Nqobile A. Masondo
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa;
| | - Mack Moyo
- Department of Horticulture, Faculty of Applied Sciences, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa;
| | - Nana M. D. Buthelezi
- Postharvest Research Laboratory, Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, P.O. Box 524, Auckland Park 2006, South Africa;
| | - Stephen O. Amoo
- Indigenous Knowledge Systems Centre, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2745, South Africa;
- Postharvest Research Laboratory, Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, P.O. Box 524, Auckland Park 2006, South Africa;
- Agricultural Research Council, Roodeplaat Vegetable and Ornamental Plants, Private Bag X293, Pretoria 0001, South Africa
| | - Lukáš Spíchal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (L.S.); (K.D.)
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (L.S.); (K.D.)
- Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
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Avni A, Golan Y, Shirron N, Shamai Y, Golumbic Y, Danin-Poleg Y, Gepstein S. From Survival to Productivity Mode: Cytokinins Allow Avoiding the Avoidance Strategy Under Stress Conditions. FRONTIERS IN PLANT SCIENCE 2020; 11:879. [PMID: 32714345 PMCID: PMC7343901 DOI: 10.3389/fpls.2020.00879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
Growth retardation and stress-induced premature plant senescence are accompanied by a severe yield reduction and raise a major agro-economic concern. To improve biomass and yield in agricultural crops under mild stress conditions, the survival must be changed to productivity mode. Our previous successful attempts to delay premature senescence and growth inhibition under abiotic stress conditions by autoregulation of cytokinins (CKs) levels constitute a generic technology toward the development of highly productive plants. Since this technology is based on the induction of CKs synthesis during the age-dependent senescence phase by a senescence-specific promoter (SARK), which is not necessarily regulated by abiotic stress conditions, we developed autoregulating transgenic plants expressing the IPT gene specifically under abiotic stress conditions. The Arabidopsis promoter of the stress-induced metallothionein gene (AtMT) was isolated, fused to the IPT gene and transformed into tobacco plants. The MT:IPT transgenic tobacco plants displayed comparable elevated biomass productivity and maintained growth under drought conditions. To decipher the role and the molecular mechanisms of CKs in reverting the survival transcriptional program to a sustainable plant growth program, we performed gene expression analysis of candidate stress-related genes and found unexpectedly clear downregulation in the CK-overproducing plants. We also investigated kinase activity after applying exogenous CKs to tobacco cell suspensions that were grown in salinity stress. In-gel kinase activity analysis demonstrated CK-dependent deactivation of several stress-related kinases including two of the MAPK components, SIPK and WIPK and the NtOSAK, a member of SnRK2 kinase family, a key component of the ABA signaling cascade. A comprehensive phosphoproteomics analysis of tobacco cells, treated with exogenous CKs under salinity-stress conditions indicated that >50% of the identified phosphoproteins involved in stress responses were dephosphorylated by CKs. We hypothesize that upregulation of CK levels under stress conditions desensitize stress signaling cues through deactivation of kinases that are normally activated under stress conditions. CK-dependent desensitization of environmental stimuli is suggested to attenuate various pathways of the avoidance syndrome including the characteristic growth arrest and the premature senescence while allowing normal growth and metabolic maintenance.
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Affiliation(s)
- Avishai Avni
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Yelena Golan
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Natali Shirron
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Yeela Shamai
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Yaela Golumbic
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Yael Danin-Poleg
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
| | - Shimon Gepstein
- Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel
- Kinneret Academic College, Sea of Galilee, Israel
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6
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Enhanced biomass production and fatty acid accumulation in Scenedesmus sp. LX1 treated with 6-benzylaminopurine. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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7
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Gujjar RS, Supaibulwatana K. The Mode of Cytokinin Functions Assisting Plant Adaptations to Osmotic Stresses. PLANTS (BASEL, SWITZERLAND) 2019; 8:E542. [PMID: 31779090 PMCID: PMC6963579 DOI: 10.3390/plants8120542] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 01/15/2023]
Abstract
Plants respond to abiotic stresses by activating a specific genetic program that supports survival by developing robust adaptive mechanisms. This leads to accelerated senescence and reduced growth, resulting in negative agro-economic impacts on crop productivity. Cytokinins (CKs) customarily regulate various biological processes in plants, including growth and development. In recent years, cytokinins have been implicated in adaptations to osmotic stresses with improved plant growth and yield. Endogenous CK content under osmotic stresses can be enhanced either by transforming plants with a bacterial isopentenyl transferase (IPT) gene under the control of a stress inducible promoter or by exogenous application of synthetic CKs. CKs counteract osmotic stress-induced premature senescence by redistributing soluble sugars and inhibiting the expression of senescence-associated genes. Elevated CK contents under osmotic stress antagonize abscisic acid (ABA) signaling and ABA mediated responses, delay leaf senescence, reduce reactive oxygen species (ROS) damage and lipid peroxidation, improve plant growth, and ameliorate osmotic stress adaptability in plants.
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Affiliation(s)
- Ranjit Singh Gujjar
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand;
- Division of Crop Improvement, Indian Institute of Sugarcane Research, Lucknow 226002, India
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8
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Synthesis of novel mesoporous carbon nanoparticles and their phytotoxicity to rice (Oryza sativa L.). JOURNAL OF SAUDI CHEMICAL SOCIETY 2019. [DOI: 10.1016/j.jscs.2018.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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9
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Apodaca SA, Medina-Velo IA, Lazarski AC, Flores-Margez JP, Peralta-Videa JR, Gardea-Torresdey JL. Different forms of copper and kinetin impacted element accumulation and macromolecule contents in kidney bean (Phaseolus vulgaris) seeds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:1534-1540. [PMID: 29913614 DOI: 10.1016/j.scitotenv.2018.04.360] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/25/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
The relationship between engineered nanomaterials and plant biostimulants is unclear. In this study, kidney bean (Phaseolus vulgaris) plants were grown to maturity (90 days) in soil amended with nano copper (nCu), bulk copper (bCu), or copper chloride (CuCl2) at 0, 50, or 100 mg kg-1, then watered with 0, 10, or 100 μM of kinetin (KN). Seeds were harvested and analyzed via ICP-OES and biochemical assays. While seed production was largely unaffected, nutritional value was significantly impacted. Accumulation of Cu was enhanced by 5-10% from controls by Cu-based treatments. Fe was the only macro/microelement significantly altered by nCu, which was ~29% lower than seeds from untreated plants. All forms of Cu combined with 10 μM KN reduced Mg from 9 to 12%. Application of KN plus bCu or CuCl2 elevated concentrations of Mn (31-41%) and S (19-22%), respectively. Protein content of seeds was stimulated (11-12%) by bCu, on average, and depressed by CuCl2 + KN (up to 22%). Variations in sugar and starch content were insignificant, compared to controls. Our results indicate that the interaction Cu × KN significantly altered the nutritional value of common beans, which has potential implications to agricultural practices incorporating Cu as either a pesticide or fertilizer.
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Affiliation(s)
- Suzanne A Apodaca
- Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso 79968, TX, United States
| | - Illya A Medina-Velo
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso 79968, TX, United States
| | - Alek C Lazarski
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States
| | - Juan P Flores-Margez
- Autonomous University of Ciudad Juárez, Departamento de Química y Biología, Instituto de Ciencias Biomédicas, Anillo envolvente PRONAF y Estocolmo, Ciudad Juárez, Chihuahua 32310, Mexico
| | - Jose R Peralta-Videa
- Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso 79968, TX, United States
| | - Jorge L Gardea-Torresdey
- Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso 79968, TX, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso 79968, TX, United States.
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10
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Hao Y, Ma C, Zhang Z, Song Y, Cao W, Guo J, Zhou G, Rui Y, Liu L, Xing B. Carbon nanomaterials alter plant physiology and soil bacterial community composition in a rice-soil-bacterial ecosystem. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 232:123-136. [PMID: 28947315 DOI: 10.1016/j.envpol.2017.09.024] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/14/2017] [Accepted: 09/09/2017] [Indexed: 06/07/2023]
Abstract
The aim of this study was to compare the toxicity effects of carbon nanomaterials (CNMs), namely fullerene (C60), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs), on a mini-ecosystem of rice grown in a loamy potted soil. We measured plant physiological and biochemical parameters and examined bacterial community composition in the CNMs-treated plant-soil system. After 30 days of exposure, all the three CNMs negatively affected the shoot height and root length of rice, significantly decreased root cortical cells diameter and resulted in shrinkage and deformation of cells, regardless of exposure doses (50 or 500 mg/kg). Additionally, at the high exposure dose of CNM, the concentrations of four phytohormones, including auxin, indoleacetic acid, brassinosteroid and gibberellin acid 4 in rice roots significantly increased as compared to the control. At the high exposure dose of MWCNTs and C60, activities of the antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) in roots increased significantly. High-throughput sequencing showed that three typical CNMs had little effect on shifting the predominant soil bacterial species, but the presence of CNMs significantly altered the composition of the bacterial community. Our results indicate that different CNMs indeed resulted in environmental toxicity to rice and soil bacterial community in the rhizosphere and suggest that CNMs themselves and their incorporated products should be reasonably used to control their release/discharge into the environment to prevent their toxic effects on living organisms and the potential risks to food safety.
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Affiliation(s)
- Yi Hao
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Chuanxin Ma
- Stockbridge School of Agriculture, University of Massachusetts Amherst, MA 01003, United States; Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, United States
| | - Zetian Zhang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Youhong Song
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Weidong Cao
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Beijing 100081, China
| | - Jing Guo
- Dow Pharma and Food Solution, The Dow Chemical Company, 1801 Larkin Center Dr. Midland, MI 48642, United States
| | - Guopeng Zhou
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Beijing 100081, China
| | - Yukui Rui
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China; Stockbridge School of Agriculture, University of Massachusetts Amherst, MA 01003, United States.
| | - Liming Liu
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts Amherst, MA 01003, United States
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11
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Jagadish KSV, Kavi Kishor PB, Bahuguna RN, von Wirén N, Sreenivasulu N. Staying Alive or Going to Die During Terminal Senescence-An Enigma Surrounding Yield Stability. FRONTIERS IN PLANT SCIENCE 2015; 6:1070. [PMID: 26648957 PMCID: PMC4663250 DOI: 10.3389/fpls.2015.01070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/16/2015] [Indexed: 05/02/2023]
Abstract
Breeding programs with the aim to enhance yield productivity under abiotic stress conditions during the reproductive stage of crops is a top priority in the era of climate change. However, the choice of exploring stay-green or senescence phenotypes, which represent an opposing physiological bearing, are explored in cereal breeding programs for enhanced yield stability to a different extent. Thus, the consideration of stay-green or senescence phenotypes is still an ongoing debate and has not been comprehensively addressed. In this review, we provide arguments for designing a target phenotype to mitigate abiotic stresses during pre- and post-anthesis in cereals with a focus on hormonal balances regulating stay-green phenotype versus remobilization. The two major hypothesis for grain yield improvement are (i) the importance of the stay-green trait to elevate grain number under pre-anthesis and anthesis stress and (ii) fine tuning the regulatory and molecular physiological mechanisms to accelerate nutrient remobilization to optimize grain quality and seed weight under post-anthesis stress. We highlight why a cautious balance in the phenotype design is essential. While stay-green phenotypes promise to be ideal for developing stress-tolerant lines during pre-anthesis and fertilization to enhance grain number and yield per se, fine-tuning efficient remobilizing behavior during seed filling might optimize grain weight, grain quality and nutrient efficiency. The proposed model provides novel and focused directions for cereal stress breeding programs to ensure better seed-set and efficient grain-filling in cereals under terminal drought and heat stress exposure.
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Affiliation(s)
| | | | | | - Nicolaus von Wirén
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Nese Sreenivasulu
- International Rice Research Institute, Metro Manila, Philippines
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
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12
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Žižková E, Dobrev PI, Muhovski Y, Hošek P, Hoyerová K, Haisel D, Procházková D, Lutts S, Motyka V, Hichri I. Tomato (Solanum lycopersicum L.) SlIPT3 and SlIPT4 isopentenyltransferases mediate salt stress response in tomato. BMC PLANT BIOLOGY 2015; 15:85. [PMID: 25888402 PMCID: PMC4404076 DOI: 10.1186/s12870-015-0415-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/06/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Cytokinins (CKs) are involved in response to various environmental cues, including salinity. It has been previously reported that enhancing CK contents improved salt stress tolerance in tomato. However, the underlying mechanisms of CK metabolism and signaling under salt stress conditions remain to be deciphered. RESULTS Two tomato isopentenyltransferases, SlIPT3 and SlIPT4, were characterized in tomato and Arabidopsis. Both proteins displayed isopentenyltransferase (IPT) activity in vitro, while their encoding genes exhibited different spatio-temporal expression patterns during tomato plant development. SlIPT3 and SlIPT4 were affected by the endogenous CK status, tightly connected with CKs feedback regulation, as revealed by hormonal treatements. In response to salt stress, SlIPT3 and SlIPT4 were strongly repressed in tomato roots, and differently affected in young and old leaves. SlIPT3 overexpression in tomato resulted in high accumulation of different CK metabolites, following modifications of CK biosynthesis-, signaling- and degradation-gene expression. In addition, 35S::SlIPT3 tomato plants displayed improved tolerance to salinity consecutive to photosynthetic pigments and K(+)/Na(+) ratio retention. Involvement of SlIPT3 and SlIPT4 in salt stress response was also observed in Arabidopsis ipt3 knock-out complemented plants, through maintenance of CK homeostasis. CONCLUSIONS SlIPT3 and SlIPT4 are functional IPTs encoded by differently expressed genes, distinctively taking part in the salinity response. The substantial participation of SlIPT3 in CK metabolism during salt stress has been determined in 35S::SlIPT3 tomato transformants, where enhancement of CKs accumulation significantly improved plant tolerance to salinity, underlining the importance of this phytohormone in stress response.
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Affiliation(s)
- Eva Žižková
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Petre I Dobrev
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Yordan Muhovski
- Département Sciences du vivant, Centre wallon de Recherches Agronomiques, Gembloux, B-5030, Belgium.
| | - Petr Hošek
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
- Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, 272 01, Czech Republic.
| | - Klára Hoyerová
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Daniel Haisel
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Dagmar Procházková
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Stanley Lutts
- Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute - Agronomy (ELI-A), Université catholique de Louvain (UCL), Louvain-la-Neuve, 1348, Belgium.
| | - Václav Motyka
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic.
| | - Imène Hichri
- Groupe de Recherche en Physiologie Végétale (GRPV), Earth and Life Institute - Agronomy (ELI-A), Université catholique de Louvain (UCL), Louvain-la-Neuve, 1348, Belgium.
- Institut National de la Recherche Agronomique, Institut Sophia Agrobiotech (ISA), UMR INRA 1355, CNRS 7254, Université de Nice-Sophia Antipolis, 400 route des Chappes, BP167, F-06903, Sophia-Antipolis Cedex, France.
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Rothstein SJ, Bi YM, Coneva V, Han M, Good A. The challenges of commercializing second-generation transgenic crop traits necessitate the development of international public sector research infrastructure. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5673-5682. [PMID: 24948680 DOI: 10.1093/jxb/eru236] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
It has been 30 years since the first transformation of a gene into a plant species, and since that time a number of biotechnology products have been developed, with the most important being insect- and herbicide-resistant crops. The development of second-generation products, including nutrient use efficiency and tolerance to important environmental stressors such as drought, has, up to this time, been less successful. This is in part due to the inherent complexities of these traits and in part due to limitations in research infrastructure necessary for public sector researchers to test their best ideas. Here we discuss lessons from previous work in the generation of the first-generation traits, as well as work from our labs and others on identifying genes for nitrogen use efficiency. We then describe some of the issues that have impeded rapid progress in this area. Finally, we propose the type of public sector organization that we feel is necessary to make advances in important second-generation traits such as nitrogen use efficiency.
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Affiliation(s)
- Steven J Rothstein
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Yong-Mei Bi
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Viktoriya Coneva
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Mei Han
- Department of Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
| | - Allen Good
- Department of Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
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Bostock RM, Pye MF, Roubtsova TV. Predisposition in plant disease: exploiting the nexus in abiotic and biotic stress perception and response. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:517-49. [PMID: 25001451 DOI: 10.1146/annurev-phyto-081211-172902] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Predisposition results from abiotic stresses occurring prior to infection that affect susceptibility of plants to disease. The environment is seldom optimal for plant growth, and even mild, episodic stresses can predispose plants to inoculum levels they would otherwise resist. Plant responses that are adaptive in the short term may conflict with those for resisting pathogens. Abiotic and biotic stress responses are coordinated by complex signaling networks involving phytohormones and reactive oxygen species (ROS). Abscisic acid (ABA) is a global regulator in stress response networks and an important phytohormone in plant-microbe interactions with systemic effects on resistance and susceptibility. However, extensive cross talk occurs among all the phytohormones during stress events, and the challenge is discerning those interactions that most influence disease. Identifying convergent points in the stress response circuitry is critically important in terms of understanding the fundamental biology that underscores the disease phenotype as well as translating research to improve stress tolerance and disease management in production systems.
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Affiliation(s)
- Richard M Bostock
- Department of Plant Pathology, University of California, Davis, California 95616; , ,
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Manjulatha M, Sreevathsa R, Kumar AM, Sudhakar C, Prasad TG, Tuteja N, Udayakumar M. Overexpression of a pea DNA helicase (PDH45) in peanut (Arachis hypogaea L.) confers improvement of cellular level tolerance and productivity under drought stress. Mol Biotechnol 2014; 56:111-25. [PMID: 23881361 DOI: 10.1007/s12033-013-9687-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Peanut, a major edible oil seed crop globally is predominantly grown under rainfed conditions and suffers yield losses due to drought. Development of drought-tolerant varieties through transgenic technology is a valid approach. Besides superior water relation traits like water mining, intrinsic cellular level tolerance mechanisms are important to sustain the growth under stress. To achieve this objective, the focus of this study was to pyramid drought adaptive traits by overexpressing a stress responsive helicase, PDH45 in the background of a genotype with superior water relations. PCR, Southern, and RT-PCR analyses confirmed stable integration and expression of the PDH45 gene in peanut transgenics. At the end of T₃ generation, eight transgenic events were identified as promising based on stress tolerance and improvement in productivity. Several transgenic lines showed stay-green phenotype and increased chlorophyll stability under stress and reduced chlorophyll retardation under etherel-induced simulated stress conditions. Stress-induced root growth was also substantially higher in the case of transformants. This was reflected in increased WUE (low Δ¹³C) and improved growth rates and productivity. The transgenics showed 17.2 and 26.75 % increase in yield under non-stress and stress conditions over wild type ascertaining the feasibility of trait pyramiding strategy for the development of drought-tolerant peanut.
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Affiliation(s)
- M Manjulatha
- Department of Botany, Sri Krishnadevaraya University, Anantapur, Andhra Pradesh, India
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17
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Gregersen PL, Culetic A, Boschian L, Krupinska K. Plant senescence and crop productivity. PLANT MOLECULAR BIOLOGY 2013; 82:603-22. [PMID: 23354836 DOI: 10.1007/s11103-013-0013-8] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 01/15/2013] [Indexed: 05/18/2023]
Abstract
Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase. Senescence might reduce crop yield when it is induced prematurely under adverse environmental conditions. This review covers the role of senescence for the productivity of crop plants. With the aim to enhance productivity, a number of functional stay-green cultivars have been selected by conventional breeding, in particular of sorghum and maize. In many cases, a positive correlation between leaf area duration and yield has been observed, although in a number of other cases, stay-green cultivars do not display significant effects with regards to productivity. In several crops, the stay-green phenotype is observed to be associated with a higher drought resistance and a better performance under low nitrogen conditions. Among the approaches used to achieve stay-green phenotypes in transgenic plants, the expression of the IPT gene under control of senescence-associated promoters has been the most successful. The promoters employed for senescence-regulated expression contain cis-elements for binding of WRKY transcription factors and factors controlled by abscisic acid. In most crops transformed with such constructs the stay-green character has led to increased biomass, but only in few cases to increased seed yield. A coincidence of drought stress resistance and stay-green trait is observed in many transgenic plants.
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Affiliation(s)
- Per L Gregersen
- Department of Molecular Biology and Genetics, Aarhus University, Forsoegsvej 1, 4200 Slagelse, Denmark
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18
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Liu MS, Li HC, Lai YM, Lo HF, Chen LFO. Proteomics and transcriptomics of broccoli subjected to exogenously supplied and transgenic senescence-induced cytokinin for amelioration of postharvest yellowing. J Proteomics 2013; 93:133-44. [PMID: 23707232 DOI: 10.1016/j.jprot.2013.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 05/01/2013] [Accepted: 05/13/2013] [Indexed: 10/26/2022]
Abstract
UNLABELLED Previously, we investigated transgenic broccoli harboring senescence-associated-gene (SAG) promoter-triggered isopentenyltransferase (ipt), which encodes the key enzyme for cytokinin (CK) synthesis and mimics the action of exogenous supplied CK in delaying postharvest senescence of broccoli. Here, we used proteomics and transcriptomics to compare the mechanisms of ipt-transgenic and N(6)-benzylaminopurine (BA) CK treatment of broccoli during postharvest storage. The 2 treatments conferred common and distinct mechanisms. BA treatment decreased the quantity of proteins involved in energy and carbohydrate metabolism and amino acid metabolism, and ipt-transgenic treatment increased that of stress-related proteins and molecular chaperones and slightly affected levels of carbohydrate metabolism proteins. Both treatments regulated genes involved in CK signaling, sugar transport, energy and carbohydrate metabolism, amino acid metabolism and lipid metabolism, although ipt-transgenic treatment to a lesser extent. BA treatment induced genes encoding molecular chaperones, whereas ipt-transgenic treatment induced stress-related genes for cellular protection during storage. Both BA and ipt-transgenic treatments acted antagonistically on ethylene functions. We propose a long-term acclimation of metabolism and protection systems with ipt-transgenic treatment of broccoli and short-term modulation of metabolism and establishment of a protection system with both BA and ipt-transgenic treatments in delaying senescence of broccoli florets. BIOLOGICAL SIGNIFICANCE Transgenic broccoli harboring senescence-associated-gene (SAG) promoter-triggered isopentenyltransferase (ipt), which encodes the key enzyme for cytokinin (CK) synthesis and N(6)-benzylaminopurine (BA) CK treated broccoli both showed retardation of postharvest senescence during storage. The mechanisms underlying the two treatments were compared. The combination of proteomic and transcriptomic evidences revealed that the 2 treatments conferred common and distinct mechanisms in delaying senescence of broccoli florets. We propose a long-term acclimation of metabolism and protection systems with ipt-transgenic treatment of broccoli and short-term modulation of metabolism and establishment of a protection system with both BA and ipt-transgenic treatments in delaying senescence of broccoli florets. This article is part of a Special Issue entitled: Translational Plant Proteomics.
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Affiliation(s)
- Mao-Sen Liu
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
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McAllister CH, Beatty PH, Good AG. Engineering nitrogen use efficient crop plants: the current status. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:1011-25. [PMID: 22607381 DOI: 10.1111/j.1467-7652.2012.00700.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In the last 40 years the amount of synthetic nitrogen (N) applied to crops has risen drastically, resulting in significant increases in yield but with considerable impacts on the environment. A requirement for crops that require decreased N fertilizer levels has been recognized in the call for a 'Second Green Revolution' and research in the field of nitrogen use efficiency (NUE) has continued to grow. This has prompted a search to identify genes that improve the NUE of crop plants, with candidate NUE genes existing in pathways relating to N uptake, assimilation, amino acid biosynthesis, C/N storage and metabolism, signalling and regulation of N metabolism and translocation, remobilization and senescence. Herein is a review of the approaches taken to determine possible NUE candidate genes, an overview of experimental study of these genes as effectors of NUE in both cereal and non-cereal plants and the processes of commercialization of enhanced NUE crop plants. Patents issued regarding increased NUE in plants as well as gene pyramiding studies are also discussed as well as future directions of NUE research.
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Effects of engineered Sinorhizobium meliloti on cytokinin synthesis and tolerance of alfalfa to extreme drought stress. Appl Environ Microbiol 2012; 78:8056-61. [PMID: 22961897 DOI: 10.1128/aem.01276-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cytokinin is required for the initiation of leguminous nitrogen fixation nodules elicited by rhizobia and the delay of the leaf senescence induced by drought stress. A few free-living rhizobia have been found to produce cytokinin. However, the effects of engineered rhizobia capable of synthesizing cytokinin on host tolerance to abiotic stresses have not yet been described. In this study, two engineered Sinorhizobium strains overproducing cytokinin were constructed. The tolerance of inoculated alfalfa plants to severe drought stress was assessed. The engineered strains, which expressed the Agrobacterium ipt gene under the control of different promoters, synthesized more zeatins than the control strain under free-living conditions, but their own growth was not affected. After a 4-week inoculation period, the effects of engineered strains on alfalfa growth and nitrogen fixation were similar to those of the control strain under nondrought conditions. After being subjected to severe drought stress, most of the alfalfa plants inoculated with engineered strains survived, and the nitrogenase activity in their root nodules showed no apparent change. A small elevation in zeatin concentration was observed in the leaves of these plants. The expression of antioxidant enzymes increased, and the level of reactive oxygen species decreased correspondingly. Although the ipt gene was transcribed in the bacteroids of engineered strains, the level of cytokinin in alfalfa nodules was identical to that of the control. These findings suggest that engineered Sinorhizobium strains synthesizing more cytokinin could improve the tolerance of alfalfa to severe drought stress without affecting alfalfa nodulation or nitrogen fixation.
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Delatorre CA, Cohen Y, Liu L, Peleg Z, Blumwald E. The regulation of the SARK promoter activity by hormones and environmental signals. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 193-194:39-47. [PMID: 22794917 DOI: 10.1016/j.plantsci.2012.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/09/2012] [Accepted: 05/10/2012] [Indexed: 06/01/2023]
Abstract
The Senescence Associated Receptor Protein Kinase (P(SARK)) promoter, fused to isopentenyltransferase (IPT) gene has been shown to promote drought tolerance in crops. We dissected P(SARK) in order to understand the various elements associated with its activation and suppression. The activity of P(SARK) was higher in mature and early senescing leaves, and abiotic stress induced its activity in mature leaves. Bioinformatics analysis suggests the interactions of multiple cis-acting elements in the control of P(SARK) activity. In vitro gel shift assays and yeast one hybrid system revealed interactions of P(SARK) with transcription factors related to abscisic acid and cytokinin response. Deletion analysis of P(SARK), fused to GUS-reporter gene was used to identify specific regions regulating transcription under senescence or during drought stress. Effects of exogenous hormonal treatments were characterized in entire plants and in leaf disk assays, and regions responsive to various hormones were defined. Our results indicate a complex interaction of plant hormones and additional factors modulating P(SARK) activity under stress resulting in a transient induction of expression.
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Affiliation(s)
- Carla A Delatorre
- Department of Plant Sciences, University of California, Davis, CA 95616, USA; Department of Crop Science, Agronomy School, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 91501970, Brazil.
| | - Yuval Cohen
- Department of Plant Sciences, University of California, Davis, CA 95616, USA; Department of Fruit Tree Sciences, Institute of Plant Sciences, Volcani Research Center (ARO), Bet Dagan, 50250, Israel.
| | - Li Liu
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Zvi Peleg
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA 95616, USA.
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Le DT, Nishiyama R, Watanabe Y, Vankova R, Tanaka M, Seki M, Ham LH, Yamaguchi-Shinozaki K, Shinozaki K, Tran LSP. Identification and expression analysis of cytokinin metabolic genes in soybean under normal and drought conditions in relation to cytokinin levels. PLoS One 2012; 7:e42411. [PMID: 22900018 PMCID: PMC3416864 DOI: 10.1371/journal.pone.0042411] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 07/04/2012] [Indexed: 01/15/2023] Open
Abstract
Cytokinins (CKs) mediate cellular responses to drought stress and targeted control of CK metabolism can be used to develop drought-tolerant plants. Aiming to manipulate CK levels to improve drought tolerance of soybean cultivars through genetic engineering of CK metabolic genes, we surveyed the soybean genome and identified 14 CK biosynthetic (isopentenyltransferase, GmIPT) and 17 CK degradative (CK dehydrogenase, GmCKX) genes. Comparative analyses of GmIPTs and GmCKXs with Arabidopsis counterparts revealed their similar architecture. The average numbers of abiotic stress-inducible cis-elements per promoter were 0.4 and 1.2 for GmIPT and GmCKX genes, respectively, suggesting that upregulation of GmCKXs, thereby reduction of CK levels, maybe the major events under abiotic stresses. Indeed, the expression of 12 GmCKX genes was upregulated by dehydration in R2 roots. Overall, the expressions of soybean CK metabolic genes in various tissues at various stages were highly responsive to drought. CK contents in various organs at the reproductive (R2) stage were also determined under well-watered and drought stress conditions. Although tRNA-type GmIPT genes were highly expressed in soybean, cis-zeatin and its derivatives were found at low concentrations. Moreover, reduction of total CK content in R2 leaves under drought was attributable to the decrease in dihydrozeatin levels, suggesting a role of this molecule in regulating soybean's responses to drought stress. Our systematic analysis of the GmIPT and GmCKX families has provided an insight into CK metabolism in soybean under drought stress and a solid foundation for in-depth characterization and future development of improved drought-tolerant soybean cultivars by manipulation of CK levels via biotechnological approach.
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Affiliation(s)
- Dung Tien Le
- Signaling Pathway Research Unit, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
- National Key Laboratory of Plant Cell Biotechnology and Agricultural Genetics Institute, Vietnamese Academy of Agricultural Science, Hanoi, Vietnam
| | - Rie Nishiyama
- Signaling Pathway Research Unit, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | - Yasuko Watanabe
- Signaling Pathway Research Unit, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | - Radomira Vankova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Maho Tanaka
- Plant Genomic Network Research Team, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | - Motoaki Seki
- Plant Genomic Network Research Team, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | - Le Huy Ham
- National Key Laboratory of Plant Cell Biotechnology and Agricultural Genetics Institute, Vietnamese Academy of Agricultural Science, Hanoi, Vietnam
| | | | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | - Lam-Son Phan Tran
- Signaling Pathway Research Unit, RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
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Ha S, Vankova R, Yamaguchi-Shinozaki K, Shinozaki K, Tran LSP. Cytokinins: metabolism and function in plant adaptation to environmental stresses. TRENDS IN PLANT SCIENCE 2012; 17:172-9. [PMID: 22236698 DOI: 10.1016/j.tplants.2011.12.005] [Citation(s) in RCA: 268] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 05/18/2023]
Abstract
In plants, the cytokinin (CK) phytohormones regulate numerous biological processes, including responses to environmental stresses, via a complex network of CK signaling. By an unknown mechanism, stress signals are perceived and transmitted through the His-Asp phosphorelay, an important component of the CK signal transduction pathway, triggering CK-responsive genes. Because of the intensive crosstalk between CKs and abscisic acid (ABA), modulation of CK levels and their signal transduction affects both ABA-dependent and ABA-independent pathways, enabling plant adaptation to adverse conditions. This review presents our current understanding of the functions of CKs and CK signaling in the regulation of plant adaptation to stress. Biotechnological strategies based on the modulation of CK levels have been examined with the aim of stabilizing agriculture yields.
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Affiliation(s)
- Sukbong Ha
- Department of Plant Biotechnology, Chonnam National University, Buk-Gu, Gwangju 500-757, Korea
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Qin H, Gu Q, Zhang J, Sun L, Kuppu S, Zhang Y, Burow M, Payton P, Blumwald E, Zhang H. Regulated expression of an isopentenyltransferase gene (IPT) in peanut significantly improves drought tolerance and increases yield under field conditions. PLANT & CELL PHYSIOLOGY 2011; 52:1904-14. [PMID: 21920877 DOI: 10.1093/pcp/pcr125] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Isopentenyltransferase (IPT) is a critical enzyme in the cytokinin biosynthetic pathway. The expression of IPT under the control of a maturation- and stress-induced promoter was shown to delay stress-induced plant senescence that resulted in an enhanced drought tolerance in both monocot and dicot plants. This report extends the earlier findings in tobacco and rice to peanut (Arachis hypogaea L.), an important oil crop and protein source. Regulated expression of IPT in peanut significantly improved drought tolerance in both laboratory and field conditions. Transgenic peanut plants maintained higher photosynthetic rates, higher stomatal conductance and higher transpiration than wild-type control plants under reduced irrigation conditions. More importantly, transgenic peanut plants produced significantly higher yields than wild-type control plants in the field, indicating a great potential for the development of crops with improved performance and yield in water-limited areas of the world.
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Affiliation(s)
- Hua Qin
- College of Life Sciences, Sichuan University, Chengdu, Sichuan Province, China
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Liu MS, Li HC, Chang YM, Wu MT, Chen LFO. Proteomic analysis of stress-related proteins in transgenic broccoli harboring a gene for cytokinin production during postharvest senescence. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 181:288-99. [PMID: 21763540 DOI: 10.1016/j.plantsci.2011.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/25/2011] [Accepted: 06/06/2011] [Indexed: 05/20/2023]
Abstract
Our previous study revealed a cytokinin-related retardation of post-harvest floret yellowing in transgenic broccoli (Brassica oleracea var. italica) that harbored the bacterial isopentenyltransferase (ipt) gene. We aimed to investigate the underlining mechanism of this delayed post-harvest senescence. We used 2D electrophoresis and liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry for a proteomics analysis of heads of ipt-transgenic and non-transgenic inbred lines of broccoli at harvest and after four days post-harvest storage. At harvest, we found an accumulation of stress-responsive proteins involved in maintenance of protein folding (putative protein disulfide isomerase, peptidyl-prolyl cis-trans isomerase and chaperonins), scavenging of reactive oxygen species (Mn superoxide dismutase), and stress protection [myrosinase-binding protein, jasmonate inducible protein, dynamin-like protein, NADH dehydrogenase (ubiquinone) Fe-S protein 1 and stress-inducible tetratricopeptide repeat-containing protein]. After four days' post-harvest storage of non-transgenic broccoli florets, the levels of proteins involved in protein folding and carbon fixation were decreased, which indicates cellular degradation and a change in metabolism toward senescence. In addition, staining for antioxidant enzyme activity of non-transgenic plants after post-harvest storage revealed a marked decrease in activity of Fe-superoxide dismutase and ascorbate peroxidase. Thus, the accumulation of stress-responsive proteins and antioxidant enzyme activity in ipt-transgenic broccoli are most likely associated with retardation of post-harvest senescence.
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Affiliation(s)
- Mao-Sen Liu
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
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Peleg Z, Reguera M, Tumimbang E, Walia H, Blumwald E. Cytokinin-mediated source/sink modifications improve drought tolerance and increase grain yield in rice under water-stress. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:747-58. [PMID: 21284800 DOI: 10.1111/j.1467-7652.2010.00584.x] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Drought is the major environmental factor limiting crop productivity worldwide. We hypothesized that it is possible to enhance drought tolerance by delaying stress-induced senescence through the stress-induced synthesis of cytokinins in crop-plants. We generated transgenic rice (Oryza sativa) plants expressing an isopentenyltransferase (IPT) gene driven by P(SARK) , a stress- and maturation-induced promoter. Plants were tested for drought tolerance at two yield-sensitive developmental stages: pre- and post-anthesis. Under both treatments, the transgenic rice plants exhibited delayed response to stress with significantly higher grain yield (GY) when compared to wild-type plants. Gene expression analysis revealed a significant shift in expression of hormone-associated genes in the transgenic plants. During water-stress (WS), P(SARK)::IPT plants displayed increased expression of brassinosteroid-related genes and repression of jasmonate-related genes. Changes in hormone homeostasis were associated with resource(s) mobilization during stress. The transgenic plants displayed differential expression of genes encoding enzymes associated with hormone synthesis and hormone-regulated pathways. These changes and associated hormonal crosstalk resulted in the modification of source/sink relationships and a stronger sink capacity of the P(SARK)::IPT plants during WS. As a result, the transgenic plants had higher GY with improved quality (nutrients and starch content).
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Affiliation(s)
- Zvi Peleg
- Department of Plant Sciences, University of California, Davis, CA, USA
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Reguera M, Peleg Z, Blumwald E. Targeting metabolic pathways for genetic engineering abiotic stress-tolerance in crops. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:186-94. [PMID: 21867784 DOI: 10.1016/j.bbagrm.2011.08.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 11/27/2022]
Abstract
Abiotic stress conditions are the major limitations in modern agriculture. Although many genes associated with plant response(s) to abiotic stresses have been indentified and used to generate stress tolerant plants, the success in producing stress-tolerant crops is limited. New technologies are providing opportunities to generate stress tolerant crops. Biotechnological approaches that emphasize the development of transgenic crops under conditions that mimic the field situation and focus on the plant reproductive stage will significantly improve the opportunities of producing stress tolerant crops. Here, we highlight recent advances and discuss the limitations that hinder the fast integration of transgenic crops into agriculture and suggest possible research directions. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress.
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Affiliation(s)
- Maria Reguera
- Department of Plant Sci.s, University of California, Davis, CA 95616, USA
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Peleg Z, Blumwald E. Hormone balance and abiotic stress tolerance in crop plants. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:290-5. [PMID: 21377404 DOI: 10.1016/j.pbi.2011.02.001] [Citation(s) in RCA: 618] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 01/26/2011] [Accepted: 02/10/2011] [Indexed: 05/18/2023]
Abstract
Plant hormones play central roles in the ability of plants to adapt to changing environments, by mediating growth, development, nutrient allocation, and source/sink transitions. Although ABA is the most studied stress-responsive hormone, the role of cytokinins, brassinosteroids, and auxins during environmental stress is emerging. Recent evidence indicated that plant hormones are involved in multiple processes. Cross-talk between the different plant hormones results in synergetic or antagonic interactions that play crucial roles in response of plants to abiotic stress. The characterization of the molecular mechanisms regulating hormone synthesis, signaling, and action are facilitating the modification of hormone biosynthetic pathways for the generation of transgenic crop plants with enhanced abiotic stress tolerance.
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Affiliation(s)
- Zvi Peleg
- Department of Plant Sciences, University of California-Davis, CA 95616, USA
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Ma QH, Liu YC. Expression of isopentenyl transferase gene (ipt) in leaf and stem delayed leaf senescence without affecting root growth. PLANT CELL REPORTS 2009; 28:1759-65. [PMID: 19820948 DOI: 10.1007/s00299-009-0776-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 09/05/2009] [Accepted: 09/19/2009] [Indexed: 05/28/2023]
Abstract
A cytokinin biosynthetic gene encoding isopentenyl transferase (ipt) was cloned with its native promoter from Agrobacterium tumefaciens and introduced into tobacco plants. Indolebutyric acid was applied in rooting medium and morphologically normal transgenic tobacco plants were regenerated. Genetic analysis of self-fertilized progeny showed that a single copy of intact ipt gene had been integrated, and T(2) progeny had become homozygous for the transgene. Stable inheritance of the intact ipt gene in T(2) progeny was verified by Southern hybridization. Northern blot hybridization revealed that the expression of this ipt gene was confined in leaves and stems but undetectable in roots of the transgenic plants. Endogenous cytokinin levels in the leaves and stems of the transgenic tobaccos were two to threefold higher than that of control, but in roots, both the transgenic and control tobaccos had similar cytokinin levels. The elevated cytokinin levels in the transgenic tobacco leaves resulted in delayed leaf senescence in terms of chlorophyll content without affecting the net photosynthetic rate. The root growth and morphology of the plant were not affected in the transgenic tobacco.
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Affiliation(s)
- Qing-Hu Ma
- Institute of Botany, Chinese Academy of Sciences, Beijing, China.
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