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Singhal C, Singh A, Sharma AK, Khurana P. Identification of CKX gene family in Morus indica cv K2 and functional characterization of MiCKX4 during abiotic stress. STRESS BIOLOGY 2024; 4:35. [PMID: 39136853 PMCID: PMC11322459 DOI: 10.1007/s44154-024-00173-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/06/2024] [Indexed: 08/16/2024]
Abstract
Cytokinin oxidase/dehydrogenase (CKX) is the key enzyme that has been observed to catalyze irreversible inactivation of cytokinins and thus modulate cytokinin levels in plants. CKX gene family is known to have few members which are, expanded in the genome mainly due to duplication events. A total of nine MiCKXs were identified in Morus indica cv K2 with almost similar gene structures and conserved motifs and domains. The cis-elements along with expression analysis of these MiCKXs revealed their contrasting and specific role in plant development across different developmental stages. The localization of these enzymes in ER and Golgi bodies signifies their functional specification and property of getting modified post-translationally to carry out their activities. The overexpression of MiCKX4, an ortholog of AtCKX4, displayed longer primary root and higher number of lateral roots. Under ABA stress also the transgenic lines showed higher number of lateral roots and tolerance against drought stress as compared to wild-type plants. In this study, the CKX gene family members were analyzed bioinformatically for their roles under abiotic stresses.
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Affiliation(s)
- Chanchal Singhal
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Arunima Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Arun Kumar Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Paramjit Khurana
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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Xu Y, Ran S, Li S, Lu J, Huang W, Zheng J, Hou M, Zhong F. Genome-Wide Identification and Abiotic Stress Expression Analysis of CKX and IPT Family Genes in Cucumber ( Cucumis sativus L.). PLANTS (BASEL, SWITZERLAND) 2024; 13:422. [PMID: 38337953 PMCID: PMC10856886 DOI: 10.3390/plants13030422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/21/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024]
Abstract
Cytokinins (CKs) are among the hormones that regulate plants' growth and development, and the CKX and IPT genes, which are CK degradation and biosynthesis genes, respectively, play important roles in fine-tuning plants' cytokinin levels. However, the current research on the function of IPT and CKX in cucumber's growth, development, and response to abiotic stress is not specific enough, and their regulatory mechanisms are still unclear. In this study, we focused on the IPT and CKX genes in cucumber, analyzed the physiological and biochemical properties of their encoded proteins, and explored their expression patterns in different tissue parts and under low light, salt stress, and drought stress. Eight CsCKX and eight CsIPT genes were identified from the cucumber genome. We constructed a phylogenetic tree from the amino acid sequences and performed prediction analyses of the cis-acting elements of the CsCKX and CsIPT promoters to determine whether CsCKXs and CsIPTs are responsive to light, abiotic stress, and different hormones. We also performed expression analysis of these genes in different tissues, and we found that CsCKXs and CsIPTs were highly expressed in roots and male flowers. Thus, they are involved in the whole growth and development process of the plant. This paper provides a reference for further research on the biological functions of CsIPT and CsCKX in regulating the growth and development of cucumber and its response to abiotic stress.
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Affiliation(s)
- Yang Xu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
| | - Shengxiang Ran
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
| | - Shuhao Li
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
| | - Junyang Lu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
| | | | - Jingyuan Zheng
- Vegetable Research Institute, Hunan Academy of Agricultural Sciences, Changsha 410128, China;
| | - Maomao Hou
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
| | - Fenglin Zhong
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Y.X.); (S.R.); (J.L.)
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Breygina M, Voronkov A, Galin I, Akhiyarova G, Polevova S, Klimenko E, Ivanov I, Kudoyarova G. Dynamics of endogenous levels and subcellular localization of ABA and cytokinins during pollen germination in spruce and tobacco. PROTOPLASMA 2023; 260:237-248. [PMID: 35579760 DOI: 10.1007/s00709-022-01766-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/24/2022] [Indexed: 06/15/2023]
Abstract
We used the enzyme-linked immunosorbent assay (ELISA) to assess the level of endogenous hormones in spruce pollen, and immunolocalization and confocal microscopy to study hormone localization in spruce and tobacco pollen. During pollen activation, the levels of ABA, zeatin, and its riboside significantly decreased. After the initiation of polar growth, the levels of all cytokinins increased sharply; ABA level also increased. In dormant spruce pollen grains, zeatin and ABA were localized uniformly throughout the cytoplasm. Zeatin was not detected in the nuclei, and the antheridial cell showed higher levels than the vegetative cell; ABA signal was detected in the cytoplasm and the nuclei. In germinating pollen, both hormones were detected mainly in plastids. The similar pattern was found in growing pollen tubes; signal from ABA also had a noticeable level in the cytosol of the tube cell, and was weaker in the antheridial cell. Zeatin fluorescence, on the other hand, was more pronounced in the antheridial cell. In non-germinated grains of tobacco, zeatin was localized mainly in organelles. ABA in dormant pollen grains demonstrated uniform localization, including the nuclei and cytoplasm of both cells. After germination, zeatin was accumulated in the plasmalemma or cell wall. ABA signal in the cytoplasm decreased; in the nuclei, it remained high. In growing tubes, the strongest zeatin and ABA signals were observed at the plasma membrane. The differences in ABA and cytokinin localization between species and dynamic changes in their level in spruce pollen highlight the key spatial and temporal parameters of hormonal regulation of gymnosperm pollen germination.
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Affiliation(s)
- Maria Breygina
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia.
| | - Alexander Voronkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow, 127276, Russia
| | - Ilshat Galin
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Guzel Akhiyarova
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Svetlana Polevova
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia
| | - Ekaterina Klimenko
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia
| | - Igor Ivanov
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Guzel Kudoyarova
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
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Chen L, Jameson GB, Guo Y, Song J, Jameson PE. The LONELY GUY gene family: from mosses to wheat, the key to the formation of active cytokinins in plants. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:625-645. [PMID: 35108444 PMCID: PMC8989509 DOI: 10.1111/pbi.13783] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 05/19/2023]
Abstract
LONELY GUY (LOG) was first identified in a screen of rice mutants with defects in meristem maintenance. In plants, LOG codes for cytokinin riboside 5'-monophosphate phosphoribohydrolase, which converts inactive cytokinin nucleotides directly to the active free bases. Many enzymes with the PGGxGTxxE motif have been misannotated as lysine decarboxylases; conversely not all enzymes containing this motif are cytokinin-specific LOGs. As LOG mutants clearly impact yield in rice, we investigated the LOG gene family in bread wheat. By interrogating the wheat (Triticum aestivum) genome database, we show that wheat has multiple LOGs. The close alignment of TaLOG1, TaLOG2 and TaLOG6 with the X-ray structures of two functional Arabidopsis thaliana LOGs allows us to infer that the wheat LOGs 1-11 are functional LOGs. Using RNA-seq data sets, we assessed TaLOG expression across 70 tissue types, their responses to various stressors, the pattern of cis-regulatory elements (CREs) and intron/exon patterns. TaLOG gene family members are expressed variously across tissue types. When the TaLOG CREs are compared with those of the cytokinin dehydrogenases (CKX) and glucosyltransferases (CGT), there is close alignment of CREs between TaLOGs and TaCKXs reflecting the key role of CKX in maintaining cytokinin homeostasis. However, we suggest that the main homeostatic mechanism controlling cytokinin levels in response to biotic and abiotic challenge resides in the CGTs, rather than LOG or CKX. However, LOG transgenics and identified mutants in rice variously impact yield, providing interesting avenues for investigation in wheat.
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Affiliation(s)
- Lei Chen
- School of Life SciencesYantai UniversityYantaiChina
| | | | - Yichu Guo
- School of Life SciencesYantai UniversityYantaiChina
| | - Jiancheng Song
- School of Life SciencesYantai UniversityYantaiChina
- Yantai Jien Biological Science & Technology LtdYEDAYantaiChina
| | - Paula E. Jameson
- School of Life SciencesYantai UniversityYantaiChina
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
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Breeze E, Mullineaux PM. The Passage of H 2O 2 from Chloroplasts to Their Associated Nucleus during Retrograde Signalling: Reflections on the Role of the Nuclear Envelope. PLANTS (BASEL, SWITZERLAND) 2022; 11:552. [PMID: 35214888 PMCID: PMC8876790 DOI: 10.3390/plants11040552] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 05/05/2023]
Abstract
The response of chloroplasts to adverse environmental cues, principally increases in light intensity, stimulates chloroplast-to-nucleus retrograde signalling, which leads to the induction of immediate protective responses and longer-term acclimation. Hydrogen peroxide (H2O2), generated during photosynthesis, is proposed to both initiate and transduce a retrograde signal in response to photoinhibitory light intensities. Signalling specificity achieved by chloroplast-sourced H2O2 for signal transduction may be dependent upon the oft-observed close association of a proportion of these organelles with the nucleus. In this review, we consider more precisely the nature of the close association between a chloroplast appressed to the nucleus and the requirement for H2O2 to cross both the double membranes of the chloroplast and nuclear envelopes. Of particular relevance is that the endoplasmic reticulum (ER) has close physical contact with chloroplasts and is contiguous with the nuclear envelope. Therefore, the perinuclear space, which transducing H2O2 molecules would have to cross, may have an oxidising environment the same as the ER lumen. Based on studies in animal cells, the ER lumen may be a significant source of H2O2 in plant cells arising from the oxidative folding of proteins. If this is the case, then there is potential for the ER lumen/perinuclear space to be an important location to modify chloroplast-to-nucleus H2O2 signal transduction and thereby introduce modulation of it by additional different environmental cues. These would include for example, heat stress and pathogen infection, which induce the unfolded protein response characterised by an increased H2O2 level in the ER lumen.
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Affiliation(s)
- Emily Breeze
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK;
| | - Philip M. Mullineaux
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
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