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Tillett BJ, Hale CO, Martin JM, Giroux MJ. Genes Impacting Grain Weight and Number in Wheat ( Triticum aestivum L. ssp. aestivum). PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11131772. [PMID: 35807724 PMCID: PMC9269389 DOI: 10.3390/plants11131772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/17/2022] [Accepted: 06/27/2022] [Indexed: 05/05/2023]
Abstract
The primary goal of common wheat (T. aestivum) breeding is increasing yield without negatively impacting the agronomic traits or product quality. Genetic approaches to improve the yield increasingly target genes that impact the grain weight and number. An energetic trade-off exists between the grain weight and grain number, the result of which is that most genes that increase the grain weight also decrease the grain number. QTL associated with grain weight and number have been identified throughout the hexaploid wheat genome, leading to the discovery of numerous genes that impact these traits. Genes that have been shown to impact these traits will be discussed in this review, including TaGNI, TaGW2, TaCKX6, TaGS5, TaDA1, WAPO1, and TaRht1. As more genes impacting the grain weight and number are characterized, the opportunity is increasingly available to improve common wheat agronomic yield by stacking the beneficial alleles. This review provides a synopsis of the genes that impact grain weight and number, and the most beneficial alleles of those genes with respect to increasing the yield in dryland and irrigated conditions. It also provides insight into some of the genetic mechanisms underpinning the trade-off between grain weight and number and their relationship to the source-to-sink pathway. These mechanisms include the plant size, the water soluble carbohydrate levels in plant tissue, the size and number of pericarp cells, the cytokinin and expansin levels in developing reproductive tissue, floral architecture and floral fertility.
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Ahmad I, Kamran M, Meng X, Ali S, Ahmad S, Gao Z, Liu T, Han Q. Hormonal changes with uniconazole trigger canopy apparent photosynthesis and grain filling in wheat crop in a semi-arid climate. PROTOPLASMA 2021; 258:139-150. [PMID: 32968872 DOI: 10.1007/s00709-020-01559-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
Phytohormones are important for the growth and development of plants. The objective of the experiment was to investigate the effect of foliar application of uniconazole (UCZ) at the four-leaf stage on hormone crosstalk and production of winter wheat. An experiment was carried out during 2015-2016 and 2016-2017 growth season in a semi-arid region, where UCZ at a concentration of 0 (CK, distilled water), 15 (FU15), 30 (FU30), and 45 (FU45) mg L-1 were sprayed on wheat crop at the four-leaf stage at a rate of 138.8 mL m-2. UCZ alters the endogenous hormone contents in flag leaves and in grains. UCZ inhibited gibberellic acid (GA) in flag leaves and in grains where the lower GA with UCZ improved the zeatin + zeatin riboside (Z + ZR) and abscisic acid (ABA) contents. The lower GA and higher Z + ZR and ABA contents with UCZ-treated plants improved the chlorophyll content and canopy apparent photosynthesis (CAP) as well as the grain-filling characteristics. The Z + ZR and ABA in flag leaves were positively correlated with chlorophyll content and CAP value while negatively with GA. Moreover, the Z + ZR and ABA were positively correlated with maximum grain weight, mean grain-filling rate, and maximum grain-filling rate, while negatively with GA level. Treatment FU30 significantly improved the chlorophyll content, CAP value, spike weight, grain-filling characteristics, and hormone contents of Z + ZR and ABA while it decreased the GA level. The hormone crosstalk with UCZ significantly increased the yield of wheat crop, where FU30 treatment performs better.
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Affiliation(s)
- Irshad Ahmad
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China.
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Muhammad Kamran
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xiangping Meng
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Shahzad Ali
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Shakeel Ahmad
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhiqiang Gao
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Tiening Liu
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Qingfang Han
- Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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Hallmark HT, Černý M, Brzobohatý B, Rashotte AM. trans-Zeatin-N-glucosides have biological activity in Arabidopsis thaliana. PLoS One 2020; 15:e0232762. [PMID: 32379789 PMCID: PMC7205299 DOI: 10.1371/journal.pone.0232762] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/21/2020] [Indexed: 11/22/2022] Open
Abstract
Cytokinin is an indispensable phytohormone responsible for physiological processes ranging from root development to leaf senescence. The term "cytokinin" refers to several dozen adenine-derived compounds occurring naturally in plants. Cytokinins (CKs) can be divided into various classes and forms; base forms are generally considered to be active while highly abundant cytokinin-N-glucosides (CKNGs), 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 over several decades in the literature that they are inactive. Here we show that exogenous application of trans-Zeatin-N-glucosides (tZNGs, a specific class of CKNGs) to Arabidopsis results in CK response comparable to the application of an active CK base. These results are most apparent in senescence assays where both a CK base (tZ) and tZNGs (tZ7G, tZ9G) delay senescence in cotyledons. Further experiments involving root growth and shoot regeneration revealed tZNGs do not always have the same effects as tZ, and have largely distinct effects on the transcriptome and proteome. These data are in contrast to previous reports of CKNGs being inactive and raise questions about the function of these compounds as well as their mechanism of action.
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Affiliation(s)
- H. Tucker Hallmark
- Department of Biological Sciences, Auburn University, Auburn, AL, United States of America
| | - Martin Černý
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic
| | - Břetislav Brzobohatý
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic
| | - Aaron M. Rashotte
- Department of Biological Sciences, Auburn University, Auburn, AL, United States of America
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic
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Gouda G, Gupta MK, Donde R, Kumar J, Parida M, Mohapatra T, Dash SK, Pradhan SK, Behera L. Characterization of haplotypes and single nucleotide polymorphisms associated with Gn1a for high grain number formation in rice plant. Genomics 2020; 112:2647-2657. [PMID: 32087244 DOI: 10.1016/j.ygeno.2020.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/07/2020] [Accepted: 02/18/2020] [Indexed: 01/03/2023]
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Copy Number Variation of Cytokinin Oxidase Gene Tackx4 Associated with Grain Weight and Chlorophyll Content of Flag Leaf in Common Wheat. PLoS One 2015; 10:e0145970. [PMID: 26714276 PMCID: PMC4699907 DOI: 10.1371/journal.pone.0145970] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/10/2015] [Indexed: 11/30/2022] Open
Abstract
As the main pigment in photosynthesis, chlorophyll significantly affects grain filling and grain weight of crop. Cytokinin (CTK) can effectively increase chlorophyll content and chloroplast stability, but it is irreversibly inactivated by cytokinin oxidase (CKX). In this study, therefore, twenty-four pairs of primers were designed to identify variations of wheat CKX (Tackx) genes associated with flag leaf chlorophyll content after anthesis, as well as grain weight in 169 recombinant inbred lines (RIL) derived from Triticum aestivum Jing 411 × Hongmangchun 21. Results indicated variation of Tackx4, identified by primer pair T19-20, was proven to significantly associate with chlorophyll content and grain weight in the RIL population. Here, two Tackx4 patterns were identified: one with two co-segregated fragments (Tackx4-1/Tackx4-2) containing 618 bp and 620 bp in size (as in Jing 411), and another with no PCR product. The two genotypes were designated as genotype-A and genotype-B, respectively. Grain weight and leaf chlorophyll content at 5~15 days after anthesis (DAA) were significantly higher in genotype-A lines than those in genotype-B lines. Mapping analysis indicated Tackx4 was closely linked to Xwmc169 on chromosome 3AL, as well as co-segregated with a major quantitative trait locus (QTL) for both grain weight and chlorophyll content of flag leaf at 5~15 DAA. This QTL explained 8.9~22.3% phenotypic variations of the two traits across four cropping seasons. Among 102 wheat varieties, a third genotype of Tackx4 was found and designated as genotype-C, also having two co-segregated fragments, Tackx4-2 and Tackx4-3 (615bp). The sequences of three fragments, Tackx4-1, Tackx4-2, and Tackx4-3, showed high identity (>98%). Therefore, these fragments could be considered as different copies at Tackx4 locus on chromosome 3AL. The effect of copy number variation (CNV) of Tackx4 was further validated. In general, genotype-A contains both significantly higher grain weight and flag leaf chlorophyll content at 5~15 DAA than those in genotype-B and genotype-C, among 102 varieties under various environments.
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Yeh SY, Chen HW, Ng CY, Lin CY, Tseng TH, Li WH, Ku MSB. Down-Regulation of Cytokinin Oxidase 2 Expression Increases Tiller Number and Improves Rice Yield. RICE (NEW YORK, N.Y.) 2015; 8:36. [PMID: 26643073 PMCID: PMC4671980 DOI: 10.1186/s12284-015-0070-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 11/29/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND Cytokinins are plant-specific hormones that affect plant growth and development. The endogenous level of cytokinins in plant cells is regulated in part by irreversible degradation via cytokinin oxidase/dehydrogenase (CKX). Among the 11 rice CKXs, CKX2 has been implicated in regulation of rice grain yield. RESULTS To specifically down-regulate OsCKX2 expression, we have chosen two conserved glycosylation regions of OsCKX2 for designing artificial short hairpin RNA interference genes (shRNA-CX3 and -CX5, representing the 5' and 3' glycosylation region sequences, respectively) for transformation by the Agrobacterium-mediated method. For each construct, 5 independent transgenic lines were obtained for detailed analysis. Southern blot analysis confirmed the integration of the shRNA genes into the rice genome, and quantitative real time RT-PCR and northern blot analyses showed reduced OsCKX2 expression in the young stem of transgenic rice at varying degrees. However, the expression of other rice CKX genes, such as CKX1 and CKX3, in these transgenic lines was not altered. Transgenic rice plants grown in the greenhouse were greener and more vigorous with delayed senescence, compared to the wild type. In field experiments, both CX3 and CX5 transgenic rice plants produced more tillers (27-81 %) and grains (24-67 %) per plant and had a heavier 1000 grain weight (5-15 %) than the wild type. The increases in grain yield were highly correlated with increased tiller numbers. Consistently, insertional activation of OsCKX2 led to increased expression of CKX2 and reduced tiller number and growth in a gene-dosage dependant manner. CONCLUSIONS Taken together, these results demonstrate that specific suppression of OsCKX2 expression through shRNA-mediated gene silencing leads to enhanced growth and productivity in rice by increasing tiller number and grain weight.
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Affiliation(s)
- Su-Ying Yeh
- Biodiversity Research Center and Genome Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Hau-Wen Chen
- Department of Bioagricultural Science, National Chiayi University, Chiayi, 600, Taiwan
| | - Chun-Yeung Ng
- Biodiversity Research Center and Genome Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Chu-Yin Lin
- Biodiversity Research Center and Genome Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Tung-Hai Tseng
- Division of Biotechnology, Taiwan Agricultural Research Institute, Taichung, 413, Taiwan
| | - Wen-Hsiung Li
- Biodiversity Research Center and Genome Research Center, Academia Sinica, Taipei, 115, Taiwan
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, 60637, USA
| | - Maurice S B Ku
- Department of Bioagricultural Science, National Chiayi University, Chiayi, 600, Taiwan.
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
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Cortleven A, Schmülling T. Regulation of chloroplast development and function by cytokinin. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4999-5013. [PMID: 25873684 DOI: 10.1093/jxb/erv132] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A role of the plant hormone cytokinin in regulating the development and activity of chloroplasts was described soon after its discovery as a plant growth regulator more than 50 years ago. Its promoting action on chloroplast ultrastructure and chlorophyll synthesis has been reported repeatedly, especially during etioplast-to-chloroplast transition. Recently, a protective role of the hormone for the photosynthetic apparatus during high light stress was shown. Details about the molecular mechanisms of cytokinin action on plastids are accumulating from genetic and transcriptomic studies. The cytokinin receptors AHK2 and AHK3 are mainly responsible for the transduction of the cytokinin signal to B-type response regulators, in particular ARR1, ARR10, and ARR12, which are transcription factors of the two-component system mediating cytokinin functions. Additional transcription factors linking cytokinin and chloroplast development include CGA1, GNC, HY5, GLK2, and CRF2. In this review, we summarize early and more recent findings of the long-known relationship between the hormone and the organelle and describe crosstalk between cytokinin, light, and other hormones during chloroplast development.
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Affiliation(s)
- Anne Cortleven
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D-14195 Berlin, Germany
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D-14195 Berlin, Germany
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Liu Y, Fang Y, Huang M, Jin Y, Sun J, Tao X, Zhang G, He K, Zhao Y, Zhao H. Uniconazole-induced starch accumulation in the bioenergy crop duckweed (Landoltia punctata) II: transcriptome alterations of pathways involved in carbohydrate metabolism and endogenous hormone crosstalk. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:64. [PMID: 25873998 PMCID: PMC4396169 DOI: 10.1186/s13068-015-0245-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/24/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND Landoltia punctata is a widely distributed duckweed species with great potential to accumulate enormous amounts of starch for bioethanol production. We found that L. punctata can accumulate starch rapidly accompanied by alterations in endogenous hormone levels after uniconazole application, but the relationship between endogenous hormones and starch accumulation is still unclear. RESULTS After spraying fronds with 800 mg/L uniconazole, L. punctata can accumulate starch quickly, with a dry weight starch content of up to 48% after 240 h of growth compared to 15.7% in the control group. Electron microscopy showed that the starch granule content was elevated after uniconazole application. The activities of key enzymes involved in starch synthesis were also significantly increased. Moreover, the expression of regulatory elements of the cytokinin (CK), abscisic acid (ABA) and gibberellin (GA) signaling pathways that are involved in chlorophyll and starch metabolism also changed correspondingly. Importantly, the expression levels of key enzymes involved in starch biosynthesis were up-regulated, while transcript-encoding enzymes involved in starch degradation and other carbohydrate metabolic branches were down-regulated. CONCLUSION The increase of endogenous ABA and CK levels positively promoted the activity of ADP-glucose pyrophosphorylase (AGPase) and chlorophyll content, while the decrease in endogenous GA levels inactivated α-amylase. Thus, the alterations of endogenous hormone levels resulted in starch accumulation due to regulation of the expression of genes involved in the starch metabolism pathway.
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Affiliation(s)
- Yang Liu
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />University of Chinese Academy of Sciences, No.19A Yuquan Road, 100049 Beijing, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Yang Fang
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Mengjun Huang
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />University of Chinese Academy of Sciences, No.19A Yuquan Road, 100049 Beijing, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Yanling Jin
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Jiaolong Sun
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Xiang Tao
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Guohua Zhang
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Kaize He
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
| | - Yun Zhao
- />Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Sciences, Sichuan University, N0.24 South Section 1, Yihuan Road, 610064 Chengdu, China
| | - Hai Zhao
- />Chengdu Institute of Biology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
- />Environmental Microbiology Key Laboratory of Sichuan Province, No.9 Section 4, Renmin Nan Road, 610041 Chengdu, China
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1,2,3-Thiadiazolyl Isocyanates in the Synthesis of Biologically Active Compounds. Study of the Cytotoxic Activity of N-(4-methyl-1,2,3-thiadi-azolyl-5-yl)-N'-(4-methylphenyl)Urea*. Chem Heterocycl Compd (N Y) 2014. [DOI: 10.1007/s10593-014-1561-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Tahbaz F. Activities of cytokinins in cucumber cotyledon assays as compared with the tobacco callus bioassay. ACTA ACUST UNITED AC 2014. [DOI: 10.1080/00378941.1977.10835751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Promotion by a Peptidyl Growth Factor, Phytosulfokine, of Chlorophyll Formation in Etiolated Cotyledon of Cucumber. Biosci Biotechnol Biochem 2014; 62:2441-3. [DOI: 10.1271/bbb.62.2441] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Rasulov B, Bichele I, Laisk A, Niinemets Ü. Competition between isoprene emission and pigment synthesis during leaf development in aspen. PLANT, CELL & ENVIRONMENT 2014; 37:724-41. [PMID: 24033429 PMCID: PMC4411569 DOI: 10.1111/pce.12190] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/17/2013] [Accepted: 08/20/2013] [Indexed: 05/18/2023]
Abstract
In growing leaves, lack of isoprene synthase (IspS) is considered responsible for delayed isoprene emission, but competition for dimethylallyl diphosphate (DMADP), the substrate for both isoprene synthesis and prenyltransferase reactions in photosynthetic pigment and phytohormone synthesis, can also play a role. We used a kinetic approach based on post-illumination isoprene decay and modelling DMADP consumption to estimate in vivo kinetic characteristics of IspS and prenyltransferase reactions, and to determine the share of DMADP use by different processes through leaf development in Populus tremula. Pigment synthesis rate was also estimated from pigment accumulation data and distribution of DMADP use from isoprene emission changes due to alendronate, a selective inhibitor of prenyltransferases. Development of photosynthetic activity and pigment synthesis occurred with the greatest rate in 1- to 5-day-old leaves when isoprene emission was absent. Isoprene emission commenced on days 5 and 6 and increased simultaneously with slowing down of pigment synthesis. In vivo Michaelis-Menten constant (Km ) values obtained were 265 nmol m(-2) (20 μm) for DMADP-consuming prenyltransferase reactions and 2560 nmol m(-2) (190 μm) for IspS. Thus, despite decelerating pigment synthesis reactions in maturing leaves, isoprene emission in young leaves was limited by both IspS activity and competition for DMADP by prenyltransferase reactions.
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Affiliation(s)
- Bahtijor Rasulov
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23 Tartu 51010, Estonia
| | - Irina Bichele
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23 Tartu 51010, Estonia
| | - Agu Laisk
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23 Tartu 51010, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
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Abd El-Fattah DA, Eweda WE, Zayed MS, Hassanein MK. Effect of carrier materials, sterilization method, and storage temperature on survival and biological activities of Azotobacter chroococcum inoculant. ANNALS OF AGRICULTURAL SCIENCES 2013; 58:111-118. [DOI: 10.1016/j.aoas.2013.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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14
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Walters DR, McRoberts N, Fitt BDL. Are green islands red herrings? Significance of green islands in plant interactions with pathogens and pests. Biol Rev Camb Philos Soc 2007; 83:79-102. [PMID: 18093233 DOI: 10.1111/j.1469-185x.2007.00033.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The term green island was first used to describe an area of living, green tissue surrounding a site of infection by an obligately biotrophic fungal pathogen, differentiated from neighbouring yellowing, senescent tissue. However, it has now been used to describe symptoms formed in response to necrotrophic fungal pathogens, virus infection and infestation by certain insects. In leaves infected by obligate biotrophs such as rust and powdery mildew pathogens, green islands are areas where senescence is retarded, photosynthetic activity is maintained and polyamines accumulate. We propose such areas, in which both host and pathogen cells are alive, be termed green bionissia. By contrast, we propose that green areas associated with leaf damage caused by toxins produced by necrotrophic fungal pathogens be termed green necronissia. A range of biotrophic/hemibiotrophic fungi and leaf-mining insects produce cytokinins and it has been suggested that this cytokinin secretion may be responsible for the green island formation. Indeed, localised cytokinin accumulation may be a common mechanism responsible for green island formation in interactions of plants with biotrophic fungi, viruses and insects. Models have been developed to study if green island formation is pathogen-mediated or host-mediated. They suggest that green bionissia on leaves infected by biotrophic fungal pathogens represent zones of host tissue, altered physiologically to allow the pathogen maximum access to nutrients early in the interaction, thus supporting early sporulation and increasing pathogen fitness. They lead to the suggestion that green islands are 'red herrings', representing no more than the consequence of the infection process and discrete changes in leaf senescence.
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Affiliation(s)
- Dale R Walters
- Crop & Soil Systems Research Group, Scottish Agricultural College, West Mains Road, Edinburgh EH9 3JG, UK.
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15
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Kastanias MA, Chrysayi-Tokousbalides M. Bioactivity of the fungal metabolite (8R,16R)-(-)-pyrenophorin on graminaceous plants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:5943-7. [PMID: 16028978 DOI: 10.1021/jf050792m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A secondary metabolite was isolated from cultures of a Drechslera avenae pathotype with host specificity to Avena sterilis and identified as the macrodiolide (8R,16R)-(-)-pyrenophorin (8,16-dimethyl-1,9-dioxa-cyclohexadeca-3,11-diene-2,5,10,13-tetraone). A considerable yield of the substance was obtained after 8-12 days of incubation at temperatures of 15-20 degrees C. The compound at a concentration of 60 microM inhibited seed germination of wild oats (Avena sterilis, A. fatua), oat (A. sativa), wheat (Triticum aestivum), and barley (Hordeum vulgare). Root growth of pregerminated seeds of the graminaceous plants was stimulated, remained unaffected, or was inhibited by pyrenophorin at 10-30, 31-50, and >51 microM, respectively. The metabolite caused abnormal chlorophyll retention in leaf sections of all five graminaceous plants, but seedling cuttings partially immersed in 1000 microM solutions remained unaffected. The rate of chlorophyll dissipation was decreased by half in leaf sections treated with pyrenophorin at 320 microM compared with the control. These findings are discussed and compared with data on the production and bioactivity of the macrodiolide (5S,8R,13S,16R)-(-)-pyrenophorol, which has a similar stereochemical configuration.
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Affiliation(s)
- Michael A Kastanias
- Pesticide Science Laboratory, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece
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16
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Ricci A, Carra A, Torelli A, Maggiali CA, Morini G, Branca C. Cytokinin-like activity of N,N'-diphenylureas. N,N'-bis-(2,3-methylenedioxyphenyl)urea and N,N'-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in apple rootstock M26 (Malus pumila Mill.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2001; 160:1055-1065. [PMID: 11297803 DOI: 10.1016/s0168-9452(01)00359-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Vegetative propagation of cuttings is a widespread method to multiplicate plants. Adventitious root formation is a key step in vegetative propagation and considerable progress has recently been made in understanding root formation. But, in spite of the efforts made, no new rooting treatments have been developed. Here, we report for the first time, that N,N'-bis-(2,3-methylenedioxyphenyl)urea and N,N'-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in microcuttings of Malus pumila Mill. rootstock M26. Roots emerge without auxin supplementation in the darkness, transfer in hormone free medium, or callus formation. With the use of different bioassays, we also demonstrate that these two diphenylurea derivatives do not show cytokinin- or auxin-like activity.
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Affiliation(s)
- A Ricci
- Dipartimento di Biologia Evolutiva e Funzionale, Via delle Scienze 11/A, I-43100, Parma, Italy
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17
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Chin-Atkins AN, Craig S, Hocart CH, Dennis ES, Chaudhury AM. Increased endogenous cytokinin in the Arabidopsis amp1 mutant corresponds with de-etiolation responses. PLANTA 1996; 198:549-556. [PMID: 28321665 DOI: 10.1007/bf00262641] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/1995] [Accepted: 07/10/1995] [Indexed: 05/03/2023]
Abstract
The high-cytokinin Arabidopsis thaliana (L.) Heynh. mutant amp1 of has been further characterised. We extend our previous work on the cytokinin level in the amp1 mutant and show that it contains high levels of endogenous cytokinins in both light- and dark-grown plants, and that amp1 can be phenocopied in the dark by growing wild-type plants on exogenous cytokinin. Previously we showed that dark-grown amp1 plants display de-etiolated characteristics such as short unhooked hypocotyls, opened cotyledons and formation of leaves. We further show that amp1 mutants display de-etiolated plastid morphology and increased levels of transcripts of light-regulated genes, indicating that in this mutant light-mediated processes are partially induced in the dark. The amp1 mutant also shows a reduced level of expression of several light-regulated genes compared with the wild type when grown in light, and has an altered dark-adaptation response when compared with the wild type. These results demonstrate an association between high cytokinin levels and de-etiolation, and we infer that cytokinin itself or a cytokinin-mediated process is involved in regulation of etiolation. The map location, phenotypes and de-etiolation responses in the amp1 mutant are different from those of previously described de-etiolated mutants such as det1, det2, cop1 and cop9. We propose a model in which cytokinin acts as a component of the induction of photomorphogenic processes via a signal transduction pathway which is independent of light.
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Affiliation(s)
- Amy N Chin-Atkins
- CSIRO Division of Plant Industry, G.P.O. Box 1600, 2601, Canberra, ACT, Australia.
- Cooperative Research Centre for Plant Science, Australian National University, G.P.O. Box 475, 2601, Canberra, ACT, Australia.
| | - Stuart Craig
- CSIRO Division of Plant Industry, G.P.O. Box 1600, 2601, Canberra, ACT, Australia
| | - Charles H Hocart
- Cooperative Research Centre for Plant Science, Australian National University, G.P.O. Box 475, 2601, Canberra, ACT, Australia
| | - Elizabeth S Dennis
- CSIRO Division of Plant Industry, G.P.O. Box 1600, 2601, Canberra, ACT, Australia
- Cooperative Research Centre for Plant Science, Australian National University, G.P.O. Box 475, 2601, Canberra, ACT, Australia
| | - Abdul M Chaudhury
- CSIRO Division of Plant Industry, G.P.O. Box 1600, 2601, Canberra, ACT, Australia
- Cooperative Research Centre for Plant Science, Australian National University, G.P.O. Box 475, 2601, Canberra, ACT, Australia
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18
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De PS, Basu PS. Content of different phytohormones and indole acetic acid metabolism in root nodules ofDerris scandens BENTH. J Basic Microbiol 1996. [DOI: 10.1002/jobm.3620360502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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19
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Chattopadhyay K, Basu P. Studies on Root Nodules of Leguminous Trees II. The Bioproduction of Different Phytohormones in Root Nodules of Samanea saman (JACQ.) MERRIL and by Its Rhizobial Microsymbiont. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/s0015-3796(89)80035-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Ricci D, Scoccianti V, Branca C. Effect of some imidazopyrimidines on tobacco callus cultures. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/11263508809429388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Contents of hormones, and indoleacetic acid metabolism in root nodules of Erythrina indicaLamk., Sesbania grandifloraPers., and Pterocarpus santalinusLinn. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0015-3796(84)80086-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Mudliar A, Bharti S. Mechanism of benzyladenine-induced chlorophyll synthesis in excised cucumber cotyledons. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0015-3796(84)80010-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Effects of 6-Benzylaminopurine and Potassium Chloride on the Greening of Detached Cucumber Cotyledons. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0044-328x(83)80085-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Dei M. Benzyladenine-induced stimulation of chlorophyll formation in attached cotyledons of etiolated cucumber seedlings. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0304-4211(83)90163-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Tanaka A, Tsuji H. Calcium-induced formation of chlorophyll b and light-harvesting chlorophyll ab-protein complex in cucumber cotyledons in the dark. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1982. [DOI: 10.1016/0005-2728(82)90138-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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26
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Lee TS, Purse JG, Pryce RJ, Horgan R, Wareing PF. Dihydroconiferyl alcohol - A cell division factor from Acer species. PLANTA 1981; 152:571-577. [PMID: 24301163 DOI: 10.1007/bf00380830] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/1981] [Accepted: 04/28/1981] [Indexed: 06/02/2023]
Abstract
A compound that stimulated growth of soybean callus was isolated from spring sap of sycamore (Acer pseudoplatanus L.). Insufficient compound was isolated to permit it to be characterised. A compound with identical properties was isolated from commercial maple syrup, the concentrated spring sap of Acer saccharum L. The compound was identified as 3-(3-methoxy-4-hydroxyphenyl)-propan-1-ol (dihydroconiferyl alcohol, DCA). DCA was also active in the tobacco callus and radish leaf senescence assays, but was inactive in four other tests for cytokinin activity. DCA acted synergistically with kinetin to promote soybean callus growth. It is concluded that DCA has properties distinct from those of purine cytokinins.
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Affiliation(s)
- T S Lee
- Sittingbourne Research Centre, Shell Research Ltd., MF9 8AG, Sittingbourne, Kent, U.K
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27
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28
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Comparative kinetics of greening in etiolated intact and excized wheat leaves. ACTA ACUST UNITED AC 1981. [DOI: 10.1007/bf01963194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Szweykowska A, Gwóźdź E, Spychała M. The Cytokinin Control of Protein Synthesis in Plants. PROCEEDINGS IN LIFE SCIENCES 1981. [DOI: 10.1007/978-3-642-68035-9_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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31
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Plastogenesis and Cytokinin Action. Cytokinin and Light Interactions in Plastid Enzyme Formation of Detached Cucurbita Cotyledons. ACTA ACUST UNITED AC 1981. [DOI: 10.1007/978-3-642-68035-9_26] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
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32
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Klyachko N, Parthier B. Cytokinin control of aminoacyl-tRNA synthetase s and ribulose-bisphosphate carboxylase in developing and and greening excised Cucurbita Cotyledons. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/s0015-3796(80)80074-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Ford M, Alhadeff M, Chapman J, Black M. A rapid and selective action of 6-benzylaminopurine on 5-aminolevulinate production in excised sunflower cotyledons. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/0304-4211(79)90127-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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35
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Kamínek M, Pačes V, Corse J, Challice JS. Effect of stereospecific hydroxylation of N(6)-(Δ (2)-Isopentenyl)adenosine on cytokinin activity. PLANTA 1979; 145:239-243. [PMID: 24317729 DOI: 10.1007/bf00454447] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/1978] [Accepted: 10/23/1978] [Indexed: 06/02/2023]
Abstract
The cytokinin activities of cis and trans ribosylzeatin isomers and that of N(6)-(Δ(2)-isopentenyl)adenosine were compared in four bioassays. The trans isomer was found to be more active than the cis isomer in stimulation of cucumber cotyledon expansion (100x), retention of chlorophyll in detached leaf pieces (7x), induction and stimulation of chlorophyll synthesis in cucumber cotyledons (20x) and of betacyanin synthesis in Amaranthus caudatus seedlings grown in the dark (60x). The N(6)-(Δ(2)-isopentenyl)adenosine adenosine was less active than the trans ribosylzeatin in all four bioassays and more active than the cis ribosylzeatin in induction and stimulation of betacyanin and chlorophyll synthesis. These results show that the hydroxylation of the trans methyl group in the N(6) side chain of N(6)-(Δ(2)-isopentenyl)adenosine increases the biological activity and that this activity is either decreased or not significantly changed when the cis methyl group is hydroxylated.
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Affiliation(s)
- M Kamínek
- Institute of Experimental Botany, Czechoslovak Academy of Sciences, 166 10, Prague 6, Czechoslovakia
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36
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37
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Schmerder B, Rabenstein F, Borriss H. Steuerung des Ergrünungsprozesses in den Kotyledonen nachgereifter Agrostemma-Embryonen durch Phytohormone. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/s0015-3796(17)30467-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Buschmann C, Sironval C. Influence of kinetin on protochlorophyll(ide) accumulation and on the Shibata shift in Raphanus seedlings. PLANTA 1978; 139:127-132. [PMID: 24414151 DOI: 10.1007/bf00387137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/1977] [Accepted: 10/24/1977] [Indexed: 06/03/2023]
Abstract
Radish seedlings (Raphanus sativus L. Saxa Treib) were grown in the dark with or without added kinetin (2 mg/l=9.29 μM). Low-temperature (77°K) fluorescence emission and absorption spectra of etiolated cotyledons were registered at increasing seedling age before and immediately, 30 s and 30 min after one 1-ms flash. Kinetin was found to induce a higher accumulation of the phototransformable protochlorophyll(ide) P657-650 in the etiolated cotyledons, especially from day 6 to day 10 after germination. The amount of the P657-650 protochlorophyll(ide) resynthesized during a 30-min dark period after a 1-ms flash decreased with seedling age. It was smaller in cotyledons from kinetin-treated seedlings at day 6 after germination and at that age only. The ability to perform the Shibata shift decreased with increasing seedling age. In cotyledons from 10- and 13-day-old seedlings, the shift was accomplished to a greater extent when the plants were grown in the presence of kinetin.
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Affiliation(s)
- C Buschmann
- Laboratory of Photobiology, University of Liège, Sart-Tilman, B-4000, Liège, Belgium
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Comparison of reversed-phase high-pressure liquid chromatography with sephadex LH-20 for cytokinin analysis of tomato root pressure exudate. J Chromatogr A 1975. [DOI: 10.1016/s0021-9673(00)97492-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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Woźny A, Szweykowska A. Effect of Cytokinins and Antibiotics on Chloroplast Development in Cotyledons of Cucumis sativus. ACTA ACUST UNITED AC 1975. [DOI: 10.1016/s0015-3796(17)30117-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Effect of some growth regulating substances and carbohydrates on chlorophyll production in Melilotus alba (Desr.) callus tissue cultures. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/s0044-328x(74)80163-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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42
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Black M, Bewley JD, Fountain D. Lettuce seed germination and cytokinins: their entry and formation. PLANTA 1974; 117:145-152. [PMID: 24458327 DOI: 10.1007/bf00390796] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/1974] [Indexed: 06/03/2023]
Abstract
Cytokinins overcome the inhibitory effect of abscisic acid on the germination of isolated embryos of Grand Rapids lettuce. We have used this fact to assess the content of cytokinins in embryos removed from intact seeds which have been supplied with these growth substances i.e. to determine hormonal uptake. The method has also been used to examine the hypothesis that phytochrome and gibberellin lead to increases in active cytokinin levels in seeds. Appreciable amounts of cytokinins enter intact seeds yet seem unable to promote germination. On the other hand, little or no cytokinin-like activity seems to result from light or gibberellin treatments. We conclude that there are unresolved difficulties inherent in the "cytokinin hypothesis" of phytochrome and gibberellin action.
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Affiliation(s)
- M Black
- Department of Biology, University of Calgary, Calgary, Alberta, Canada
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43
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Kamínek M, Luštinec J. Reduced chlorophyll synthesis in cytokinin-autonomous strains of tobacco callus. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/s0044-328x(74)80145-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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44
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Einfluß von Cytokininen auf wachstum und differenzierung in vitro kultivierter protokorme von Cymbidium. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/s0044-328x(74)80074-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Langille A, Forsline P. Influence of temperature and photoperiod on cytokinin pools in the potato, Solanum tuberosum L. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/0304-4211(74)90115-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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