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Prerostova S, Dobrev PI, Kramna B, Gaudinova A, Knirsch V, Spichal L, Zatloukal M, Vankova R. Heat Acclimation and Inhibition of Cytokinin Degradation Positively Affect Heat Stress Tolerance of Arabidopsis. Front Plant Sci 2020; 11:87. [PMID: 32133021 PMCID: PMC7040172 DOI: 10.3389/fpls.2020.00087] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/21/2020] [Indexed: 05/20/2023]
Abstract
In order to pinpoint phytohormone changes associated with enhanced heat stress tolerance, the complex phytohormone profiles [cytokinins, auxin, abscisic acid (ABA), jasmonic acid (JA), salicylic acid and ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC)] were compared in Arabidopsis thaliana after direct heat shock (45°C, 3 h) and in heat-stressed pre-acclimated plants (1 h at 37°C followed by 2 h at optimal temperature 20°C). Organ-specific responses were followed in shoot apices, leaves, and roots immediately after heat shock and after 24-h recovery at 20°C. The stress strength was evaluated via membrane ion leakage and the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) and antioxidant enzymes [superoxide dismutases, guaiacol peroxidases (POD), catalases, ascorbate peroxidases (APX)]. Heat acclimation diminished negative effects of heat stress, especially in apices and roots, no significant differences being observed in leaves. Low NOX1-3 activities indicated diminished production of reactive oxygen species. Higher activity of APX, POD1, and the occurrence of POD3-4 reflected acclimation-stimulated readiness of the antioxidant system. Acclimation diminished heat shock-induced changes of ABA, JA, cytokinin, and auxin levels in apices. Excess of ABA catabolites suggested an early stress response. The strong up-regulation of ABA and ACC in roots indicated defense boost in roots of acclimated plants compared to the non-acclimated ones. To evaluate the possibility to enhance stress tolerance by cytokinin pool modulation, INCYDE-F, an inhibitor of cytokinin oxidase/dehydrogenase, was applied. As cytokinin effects on stress tolerance may depend on timing of their regulation, INCYDE was applied at several time-points. In combination with acclimation, INCYDE treatment had a slight positive effect on heat stress tolerance, mainly when applied after 2-h period of the optimal temperature. INCYDE increased contents of cytokinins trans-zeatin and cis-zeatin in roots and auxin in all tissues after heat shock. INCYDE also helped to suppress the content of ABA in leaves, and ethylene in apices and roots. INCYDE application to non-acclimated plants (applied before or after heat shock) strengthened negative stress effects, probably by delaying of the repair processes. In conclusion, pre-treatment with moderately elevated temperature enhanced heat stress tolerance and accelerated recovery after stress. Inhibition of cytokinin degradation by INCYDE slightly improved recovery of acclimated plants.
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Affiliation(s)
- Sylva Prerostova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Sylva Prerostova,
| | - Petre I. Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Barbara Kramna
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Alena Gaudinova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Vojtech Knirsch
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
| | - Lukas Spichal
- Department of Chemical Biology and Genetics, Centre of the Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc, Czechia
| | - Marek Zatloukal
- Department of Chemical Biology and Genetics, Centre of the Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc, Czechia
| | - Radomira Vankova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
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Prerostova S, Dobrev PI, Konradyova V, Knirsch V, Gaudinova A, Kramna B, Kazda J, Ludwig-Müller J, Vankova R. Hormonal Responses to Plasmodiophora brassicae Infection in Brassica napus Cultivars Differing in Their Pathogen Resistance. Int J Mol Sci 2018; 19:E4024. [PMID: 30551560 PMCID: PMC6321006 DOI: 10.3390/ijms19124024] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/27/2022] Open
Abstract
Hormonal dynamics after Plasmodiophora brassicae infection were compared in two Brassica napus cultivars-more resistant SY Alister and more sensitive Hornet, in order to elucidate responses associated with efficient defense. Both cultivars responded to infection by the early transient elevation of active cytokinins (predominantly cis-zeatin) and auxin indole-3-acetic acid (IAA) in leaves and roots, which was longer in Hornet. Moderate IAA levels in Hornet roots coincided with a high expression of biosynthetic gene nitrilase NIT1 (contrary to TAA1, YUC8, YUC9). Alister had a higher basal level of salicylic acid (SA), and it stimulated its production (via the expression of isochorismate synthase (ICS1)) in roots earlier than Hornet. Gall formation stimulated cytokinin, auxin, and SA levels-with a maximum 22 days after inoculation (dai). SA marker gene PR1 expression was the most profound at the time point where gall formation began, in leaves, roots, and especially in galls. Jasmonic acid (JA) was higher in Hornet than in Alister during the whole experiment. To investigate SA and JA function, SA was applied before infection, and twice (before infection and 15 dai), and JA at 15 dai. Double SA application diminished gall formation in Alister, and JA promoted gall formation in both cultivars. Activation of SA/JA pathways reflects the main differences in clubroot resistance.
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Affiliation(s)
- Sylva Prerostova
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Petre I Dobrev
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Veronika Konradyova
- Faculty of Agrobiology, Food and Natural Resources, Department of Plant Protection, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague 6, Czech Republic.
| | - Vojtech Knirsch
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Alena Gaudinova
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Barbara Kramna
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
- Department of Experimental Plant Biology, Charles University, Faculty of Science, Vinicna 5, 128 44 Prague 2, Czech Republic.
| | - Jan Kazda
- Faculty of Agrobiology, Food and Natural Resources, Department of Plant Protection, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague 6, Czech Republic.
| | - Jutta Ludwig-Müller
- Dresden, Faculty of Biology, Institute of Botany, Technische Universität, 01062 Dresden, Germany.
| | - Radomira Vankova
- Institute of Experimental Botany Czech Acad Sci, Laboratory of Hormonal Regulations in Plants, Rozvojova 263, 165 02 Prague 6, Czech Republic.
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