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Sharma A, Pridgeon AJ, Liu W, Segers F, Sharma B, Jenkins GI, Franklin KA. ELONGATED HYPOCOTYL5 (HY5) and HY5 HOMOLOGUE (HYH) maintain shade avoidance suppression in UV-B. Plant J 2023; 115:1394-1407. [PMID: 37243898 PMCID: PMC10953383 DOI: 10.1111/tpj.16328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/17/2023] [Accepted: 05/23/2023] [Indexed: 05/29/2023]
Abstract
Reductions in red to far-red ratio (R:FR) provide plants with an unambiguous signal of vegetational shade and are monitored by phytochrome photoreceptors. Plants integrate this information with other environmental cues to determine the proximity and density of encroaching vegetation. Shade-sensitive species respond to reductions in R:FR by initiating a suite of developmental adaptations termed shade avoidance. These include the elongation of stems to facilitate light foraging. Hypocotyl elongation is driven by increased auxin biosynthesis promoted by PHYTOCHROME INTERACTING FACTORs (PIF) 4, 5 and 7. UV-B perceived by the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor rapidly inhibits shade avoidance, in part by suppressing PIF4/5 transcript accumulation and destabilising PIF4/5 protein. Here, we show that longer-term inhibition of shade avoidance is sustained by ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOGUE (HYH), which regulate transcriptional reprogramming of genes involved in hormone signalling and cell wall modification. HY5 and HYH are elevated in UV-B and suppress the expression of XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE (XTH) genes involved in cell wall loosening. They additionally increase expression GA2-OXIDASE1 (GA2ox1) and GA2ox2, encoding gibberellin catabolism enzymes that act redundantly to stabilise the PIF-inhibiting DELLA proteins. UVR8 therefore regulates temporally distinct signalling pathways to first rapidly inhibit and subsequently maintain suppression of shade avoidance following UV-B exposure.
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Affiliation(s)
- Ashutosh Sharma
- School of Biological Sciences, Life Sciences BuildingUniversity of BristolBristolBS8 1TQUK
| | - Ashley J. Pridgeon
- School of Biological Sciences, Life Sciences BuildingUniversity of BristolBristolBS8 1TQUK
| | - Wei Liu
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowG12 8QQUK
| | - Francisca Segers
- School of Biological Sciences, Life Sciences BuildingUniversity of BristolBristolBS8 1TQUK
| | - Bhavana Sharma
- School of Biological Sciences, Life Sciences BuildingUniversity of BristolBristolBS8 1TQUK
| | - Gareth I. Jenkins
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowG12 8QQUK
| | - Keara A. Franklin
- School of Biological Sciences, Life Sciences BuildingUniversity of BristolBristolBS8 1TQUK
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2
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Panter PE, Seifert J, Dale M, Pridgeon AJ, Hulme R, Ramsay N, Contera S, Knight H. Cell wall fucosylation in Arabidopsis influences control of leaf water loss and alters stomatal development and mechanical properties. J Exp Bot 2023; 74:2680-2691. [PMID: 36715637 PMCID: PMC10112686 DOI: 10.1093/jxb/erad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 01/27/2023] [Indexed: 06/06/2023]
Abstract
The Arabidopsis sensitive-to-freezing8 (sfr8) mutant exhibits reduced cell wall (CW) fucose levels and compromised freezing tolerance. To examine whether CW fucosylation also affects the response to desiccation, we tested the effect of leaf excision in sfr8 and the allelic mutant mur1-1. Leaf water loss was strikingly higher than in the wild type in these, but not other, fucosylation mutants. We hypothesized that reduced fucosylation in guard cell (GC) walls might limit stomatal closure through altering mechanical properties. Multifrequency atomic force microscopy (AFM) measurements revealed a reduced elastic modulus (E'), representing reduced stiffness, in sfr8 GC walls. Interestingly, however, we discovered a compensatory mechanism whereby a concomitant reduction in the storage modulus (E'') maintained a wild-type viscoelastic time response (tau) in sfr8. Stomata in intact leaf discs of sfr8 responded normally to a closure stimulus, abscisic acid, suggesting that the time response may relate more to closure properties than stiffness does. sfr8 stomatal pore complexes were larger than those of the wild type, and GCs lacked a fully developed cuticular ledge, both potential contributors to the greater leaf water loss in sfr8. We present data that indicate that fucosylation-dependent dimerization of the CW pectic domain rhamnogalacturonan-II may be essential for normal cuticular ledge development and leaf water retention.
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Affiliation(s)
- Paige E Panter
- Department of Biosciences, Durham University, South Road, Durham, UK
| | - Jacob Seifert
- Department of Physics, University of Oxford, Parks Road, Oxford, UK
| | - Maeve Dale
- Department of Biosciences, Durham University, South Road, Durham, UK
- School of Biological Sciences, University of Bristol, Bristol, UK
| | | | - Rachel Hulme
- Department of Biosciences, Durham University, South Road, Durham, UK
| | - Nathan Ramsay
- Department of Biosciences, Durham University, South Road, Durham, UK
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Sun P, Isner JC, Coupel-Ledru A, Zhang Q, Pridgeon AJ, He Y, Menguer PK, Miller AJ, Sanders D, Mcgrath SP, Noothong F, Liang YK, Hetherington AM. Countering elevated CO 2 induced Fe and Zn reduction in Arabidopsis seeds. New Phytol 2022; 235:1796-1806. [PMID: 35637611 DOI: 10.1111/nph.18290] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 05/17/2022] [Indexed: 05/27/2023]
Abstract
Growth at increased concentrations of CO2 induces a reduction in seed zinc (Zn) and iron (Fe). Using Arabidopsis thaliana, we investigated whether this could be mitigated by reducing the elevated CO2 -induced decrease in transpiration. We used an infrared imaging-based screen to isolate mutants in At1g08080 that encodes ALPHA CARBONIC ANHYDRASE 7 (ACA7). aca7 mutant alleles display wild-type (WT) responses to abscisic acid (ABA) and light but are compromised in their response to elevated CO2 . ACA7 is expressed in guard cells. When aca7 mutants are grown at 1000 ppm CO2 they exhibit higher transpiration and higher seed Fe and Zn content than WT grown under the same conditions. Our data show that by increasing transpiration it is possible to partially mitigate the reduction in seed Fe and Zn content when Arabidopsis is grown at elevated CO2 .
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Affiliation(s)
- Peng Sun
- Department of Plant Sciences, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Jean-Charles Isner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Aude Coupel-Ledru
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- Institut Agro, LEPSE, INRAE, University of Montpellier, Montpellier, 75338 Cedex 07, France
| | - Qi Zhang
- Department of Plant Sciences, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Ashley J Pridgeon
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Yaqian He
- Department of Plant Sciences, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Paloma K Menguer
- Centro de Biotechnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501970, Brazil
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | - Dale Sanders
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Steve P Mcgrath
- Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Fonthip Noothong
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Yun-Kuan Liang
- Department of Plant Sciences, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Alistair M Hetherington
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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Pridgeon AJ, Hetherington AM. ABA signalling and metabolism are not essential for dark-induced stomatal closure but affect response speed. Sci Rep 2021; 11:5751. [PMID: 33707501 PMCID: PMC7952387 DOI: 10.1038/s41598-021-84911-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/17/2021] [Indexed: 11/16/2022] Open
Abstract
Stomata are microscopic pores that open and close, acting to balance CO2 uptake with water loss. Stomata close in response to various signals including the drought hormone abscisic acid (ABA), microbe-associated-molecular-patterns, high CO2 levels, and darkness. The signalling pathways underlying ABA-induced stomatal closure are well known, however, the mechanism for dark-induced stomatal closure is less clear. ABA signalling has been suggested to play a role in dark-induced stomatal closure, but it is unclear how this occurs. Here we investigate the role of ABA in promoting dark-induced stomatal closure. Tracking stomatal movements on the surface of leaf discs we find, although steady state stomatal apertures are affected by mutations in ABA signalling and metabolism genes, all mutants investigated close in response to darkness. However, we observed a delayed response to darkness for certain ABA signalling and metabolism mutants. Investigating this further in the quadruple ABA receptor mutant (pyr1pyl1pyl2pyl4), compared with wild-type, we found reduced stomatal conductance kinetics. Although our results suggest a non-essential role for ABA in dark-induced stomatal closure, we show that ABA modulates the speed of the dark-induced closure response. These results highlight the role of ABA signalling and metabolic pathways as potential targets for enhancing stomatal movement kinetics.
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Affiliation(s)
- Ashley J Pridgeon
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
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Isner JC, Olteanu VA, Hetherington AJ, Coupel-Ledru A, Sun P, Pridgeon AJ, Jones GS, Oates M, Williams TA, Maathuis FJM, Kift R, Webb AR, Gough J, Franklin KA, Hetherington AM. Short- and Long-Term Effects of UVA on Arabidopsis Are Mediated by a Novel cGMP Phosphodiesterase. Curr Biol 2019; 29:2580-2585.e4. [PMID: 31353185 PMCID: PMC6692503 DOI: 10.1016/j.cub.2019.06.071] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 06/05/2019] [Accepted: 06/24/2019] [Indexed: 12/21/2022]
Abstract
Although UVA radiation (315-400 nm) represents 95% of the UV radiation reaching the earth's surface, surprisingly little is known about its effects on plants [1]. We show that in Arabidopsis, short-term exposure to UVA inhibits the opening of stomata, and this requires a reduction in the cytosolic level of cGMP. This process is independent of UVR8, the UVB receptor. A cGMP-activated phosphodiesterase (AtCN-PDE1) was responsible for the UVA-induced decrease in cGMP in Arabidopsis. AtCN-PDE1-like proteins form a clade within the large HD-domain/PDEase-like protein superfamily, but no eukaryotic members of this subfamily have been functionally characterized. These genes have been lost from the genomes of metazoans but are otherwise conserved as single-copy genes across the tree of life. In longer-term experiments, UVA radiation increased growth and decreased water-use efficiency. These experiments revealed that PDE1 is also a negative regulator of growth. As the PDE1 gene is ancient and not represented in animal lineages, it is likely that at least one element of cGMP signaling in plants has evolved differently to the system present in metazoans.
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Affiliation(s)
- Jean-Charles Isner
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Vlad-Aris Olteanu
- Department of Computer Science, Merchant Venturers Building, University of Bristol, Woodland Road, Bristol BS8 1UB, UK
| | | | - Aude Coupel-Ledru
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Peng Sun
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Ashley J Pridgeon
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Glyndyr S Jones
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Matthew Oates
- Department of Computer Science, Merchant Venturers Building, University of Bristol, Woodland Road, Bristol BS8 1UB, UK
| | - Tom A Williams
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | | | - Richard Kift
- School of Earth and Environmental Sciences, University of Manchester, Simon Building, Oxford Road, Manchester M13 9PL, UK
| | - Ann R Webb
- School of Earth and Environmental Sciences, University of Manchester, Simon Building, Oxford Road, Manchester M13 9PL, UK
| | - Julian Gough
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QU, UK
| | - Keara A Franklin
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK.
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6
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Abstract
Takahashi et al. (2018) report that the peptide CLE25 together with the BAM1, BAM3 LRR receptor-like kinases are involved in root-to-shoot communication during dehydration stress in Arabidopsis.
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Affiliation(s)
- Deirdre H McLachlan
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Ashley J Pridgeon
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
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