MODIFICATION OF BARLEY PLANT PRODUCTIVITY THROUGH REGULATION OF CYTOKININ CONTENT BY REVERSE-GENETICS APPROACHES
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ABSTRACT:
ORGANISM(S): Hordeum vulgare
PROVIDER: GSE119154 | GEO | 2018/08/29
REPOSITORIES: GEO
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Project description:Cytokinins (CKs) are a class of plant hormones that regulate many aspects of growth and development, including cell division, apical dominance, leaf senescence, nutrient signaling, and shoot differentiation. In the past decade, substantial progress has been made in understanding CK biosynthesis, metabolism and signal transduction. Much of this knowledge is based on research in Arabidopsis, a dicotyledonous model plant. Although cytokinin plays an important role for growth and development in the Gramineae, our knowledge of cytokinin responsive genes in monocotyledonous species is very limited compared to Arabidopsis. The search for genes whose expression is modified by CK has yielded a number of valuable tools that have been used to understand CK signaling and the complex developmental processes under control of this hormone. We tried to identify rice genes regulated by CK using an Affymetrix rice genome array. Keywords: time_course; hormone_response; organ_specific_response
2007-02-15 | GSE6719 | GEO
Project description: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.
2021-09-09 | PXD019418 | Pride
Project description:One-step and two-step pathways are proposed to synthesize cytokinin. One-step pathway is mediated by LONELY GUY (LOG) proteins. However, the enzyme for two-step pathway has not been identified yet. Here, we show that a QTL GY3 boosts grain yield by more than 20% via manipulating two-step pathway. GY3 encodes a LOG protein that acts as a 5’-ribonucleotide phosphohydrolase by excessive consuming the cytokinin precursors, which contrasts with the activity of canonical LOG members as phosphoribohydrolases in a one-step pathway. The residue S41 of GY3 is crucial for the dephosphorylation of iPRMP. A solo-LTR insertion within the promoter of GY3 suppressed its expression and resulted in a higher content of active cytokinins in young panicles. Introgression of GY302428 increased grain yield per plot by 7.4% to 16.3% in all investigated indica backgrounds both under long-day and short-day conditions, which demonstrates the great value of GY302428 in indica rice production.
2023-05-05 | GSE231360 | GEO
Project description:Cytokinin is an indispensable phytohormone responsible for a number of physiological processes ranging from root development to leaf senescence. The term “cytokinin” refers to several dozen adenine-derived compounds which occur naturally in plants, including the model plant Arabidopsis thaliana. Cytokinins (CKs) can be divided up into various classes and forms; the base forms are generally considered to be active while highly abundant cytokinin-N-glucosides (CKNGs), which are composed of a CK base irreversibly conjugated to a glucose molecule, are considered inactive. However, results from early CK studies suggest CKNGs do not always lack activity despite the perpetuation in the literature that they are inactive. Here we show that exogenous application of CKNGs to Arabidopsis tissue results in a CK response comparable to the application of an active CK base. These results are most apparent in senescence assays in which both a CK base (tZ) and CKNGs (tZ7G, tZ9G) delay senescence in cotyledons. Further physiological experiments involving root growth and shoot regeneration revealed CKNGs do not always have the same effects as CK bases, and these compounds have largely distinct effects on the transcriptome, as well as the proteome. These data are in direct contradiction to previous reports of CKNGs being inactive and raise questions about the function of these compounds as well as their mechanism of action. Because CKNGs make up the majority of CKs in Arabidopsis and other Angiosperms, it is especially important to understand their physiological effects in order to have a more holistic understanding of this essential phytohormone.
2020-05-27 | PXD016087 | Pride
Project description:The transition of skotomorphogenesis to photomorphogenesis is induced by the perception of light and is characterized by the inhibition of hypocotyl elongation and opening of cotyledons. Although it is known that the plant hormone cytokinin, when applied in high concentrations, inhibits hypocotyl elongation in the dark-grown Arabidopsis plants, it is unclear to what extent this response is the result of cytokinin alone or cytokinin-induced ethylene production. We show that treatment of etiolated seedlings in presence of ethylene inhibitors (eg. AgNO3) or treatment of the ethylene-resistant mutant ein2, resulted in a significant inhibition of hypocotyl elongation. This indicates that cytokinin induced de-etiolation is largely independent of ethylene and suggests a close connection between the cytokinin two component system and the light singalling networks. We show that this cytokinin signal is mainly mediated through the cytokinin receptor ARIBIDOPSIS HISTIDIN KINASE 3 (AHK3) and the ARABIDOPSIS RESPONSE REGULATORS 1 (ARR1) in combination with ARR12. Interestingly, mutation of COP1, DET1 and CIN4/COP10 renders plants insensitive to cytokinin and these factors are indispensable for the transcriptional response during cytokinin induced de-etiolation which indicates that a functional light signaling pathway is essential for this cytokinin response. In addition, the cytokinin effect on hypocotyl elongation is highly dependent on the ambient light conditions where higher light intensities causes a switch in the response to CK from an inhibitor to a promoter of hypocotyl elongation.
2018-10-01 | GSE108912 | GEO
Project description:Cytokinins (CKs) are a class of plant hormones that regulate many aspects of growth and development, including cell division, apical dominance, leaf senescence, nutrient signaling, and shoot differentiation. In the past decade, substantial progress has been made in understanding CK biosynthesis, metabolism and signal transduction. Much of this knowledge is based on research in Arabidopsis, a dicotyledonous model plant. The current model of the CK signaling pathway is a multi-step His-Asp phosphorelay system. Some of the cytokinin-inducible response regulators are thought to act as negative regulators of CK signaling. We tried to identify rice genes regulated by CK-inducible response regulator using an Affymetrix rice genome array and transgenic rice that over-express OsRR6. Keywords: genetic modification
2007-02-15 | GSE6720 | GEO
Project description:To understand the role of cytokinins (CKs) in salt stress response, we have employed transcriptional profiling of the CK-deficient mutant, ipt1,3,5,7 and wild type plant, Col-0 under high salinity and control conditions to identify genes differentially expressed in ipt1,3,5,7 under salt stress and control conditions. Agilent's Whole Arabidopsis Gene Expression Microarray (G2519F, V4, 4x44K) was used.
2012-01-23 | GSE32087 | GEO
Project description:Cytokinin is a phytohormone involved in the regulation of diverse developmental and physiological processes in plants. Its potential for biotechnology and development of high-yield and more resilient plants has been recognized, but the molecular mechanisms behind its action are far from understood. In this report, the roots of barley seedling were explored as a new tool to reveal as yet unknown cytokinin-responsive proteins. Significant differences were reproducibly observed for 176 proteins, and at least some of the revealed cytokinin-responsive pathways were confirmed in metabolome analysis, including alterations in phenylpropanoid pathway, amino acid biosynthesis or ROS metabolism. Bioinformatics analysis indicated a significant overlap between cytokinin response and response to abiotic stress. This was confirmed by comparing proteome and metabolome profiles in response to drought, salinity or a period of temperature stress. The results illustrate complex abiotic stress response in the early development of model crop plant and confirm an extensive crosstalk between plant hormone cytokinin and response to temperature stimuli, water availability or salinity.
2020-10-06 | PXD020627 | Pride
Project description:Melatonin, a natural phytohormone present in most plants, plays multiple roles in plant growth and stress responses. Although melatonin biosynthesis-related genes have been suggested to possess diverse biological functions, their roles and functional mechanisms in regulating rice grain yield remain largely unexplored. Here, we revealed that a rice caffeic acid O-methyltransferase (OsCOMT) gene is involved in melatonin biosynthesis through in vitro and in vivo evidences. Transgenic assays show OsCOMT significantly delays leaf senescence at the grain filling stage, and then improves photosynthesis efficiency. Further experimental and transcriptomic data suggest that OsCOMT inhibits the degradation of chlorophyll and chloroplast, which in turn delay leaf senescence. Histological analysis also reveals the role of OsCOMT in the development of vascular bundle system in rice. The levels of melatonin and cytokinin were significantly increased in the culm of OsCOMT-overexpression plant relative to those of the wild-type (WT). In the OsCOMT-overexpression line, the cytokinin-biosynthesizing genes were up-regulated and the cytokinin-degrading genes were down-regulated, thereby increasing the cytokinin levels compared with the WT. Thus, OsCOMT-mediated vascular patterning may result from the crosstalk between melatonin and cytokinin. More importantly, OsCOMT significantly increased grain number and yield production of rice in various background, including Nipponbare (NIP) and Suken118 (SK118). Our findings show novel insights into melatonin-mediated leaf senescence and vascular patterning, and provide a new strategy to enhance rice yield production.
2021-11-12 | GSE184400 | GEO
Project description:To understand the role of cytokinins (CKs) in salt stress response, we have employed transcriptional profiling of the CK-deficient mutant, ipt1,3,5,7 and wild type plant, Col-0 under high salinity and control conditions to identify genes differentially expressed in ipt1,3,5,7 under salt stress and control conditions. Agilent's Whole Arabidopsis Gene Expression Microarray (G2519F, V4, 4x44K) was used. 10-d-old plants grown on GM medium (22ºC, 16-h-light/8-h-dark) were transfered onto 1/2 MS agar plates without sucrose containing either 0 or 200 mM NaCl. Independent biological samples, 10 plants/each biological replicate, were collected after 24 hours. Total RNA was prepared and used for the microarray hybridization. Three replicative hybridization experiments were carried out for each independent biological sample.
2012-01-23 | E-GEOD-32087 | biostudies-arrayexpress