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Davis W, Endo M, Locke JCW. Spatially specific mechanisms and functions of the plant circadian clock. PLANT PHYSIOLOGY 2022; 190:938-951. [PMID: 35640123 PMCID: PMC9516738 DOI: 10.1093/plphys/kiac236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Like many organisms, plants have evolved a genetic network, the circadian clock, to coordinate processes with day/night cycles. In plants, the clock is a pervasive regulator of development and modulates many aspects of physiology. Clock-regulated processes range from the correct timing of growth and cell division to interactions with the root microbiome. Recently developed techniques, such as single-cell time-lapse microscopy and single-cell RNA-seq, are beginning to revolutionize our understanding of this clock regulation, revealing a surprising degree of organ, tissue, and cell-type specificity. In this review, we highlight recent advances in our spatial view of the clock across the plant, both in terms of how it is regulated and how it regulates a diversity of output processes. We outline how understanding these spatially specific functions will help reveal the range of ways that the clock provides a fitness benefit for the plant.
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Affiliation(s)
- William Davis
- Sainsbury Laboratory, University of Cambridge, Cambridge, UK
| | - Motomu Endo
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - James C W Locke
- Sainsbury Laboratory, University of Cambridge, Cambridge, UK
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Gleadow RM, McKinley BA, Blomstedt CK, Lamb AC, Møller BL, Mullet JE. Regulation of dhurrin pathway gene expression during Sorghum bicolor development. PLANTA 2021; 254:119. [PMID: 34762174 PMCID: PMC8585852 DOI: 10.1007/s00425-021-03774-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Developmental and organ-specific expression of genes in dhurrin biosynthesis, bio-activation, and recycling offers dynamic metabolic responses optimizing growth and defence responses in Sorghum. Plant defence models evaluate the costs and benefits of resource investments at different stages in the life cycle. Poor understanding of the molecular regulation of defence deployment and remobilization hampers accuracy of the predictions. Cyanogenic glucosides, such as dhurrin are phytoanticipins that release hydrogen cyanide upon bio-activation. In this study, RNA-seq was used to investigate the expression of genes involved in the biosynthesis, bio-activation and recycling of dhurrin in Sorghum bicolor. Genes involved in dhurrin biosynthesis were highly expressed in all young developing vegetative tissues (leaves, leaf sheath, roots, stems), tiller buds and imbibing seeds and showed gene specific peaks of expression in leaves during diel cycles. Genes involved in dhurrin bio-activation were expressed early in organ development with organ-specific expression patterns. Genes involved in recycling were expressed at similar levels in the different organ during development, although post-floral initiation when nutrients are remobilized for grain filling, expression of GSTL1 decreased > tenfold in leaves and NITB2 increased > tenfold in stems. Results are consistent with the establishment of a pre-emptive defence in young tissues and regulated recycling related to organ senescence and increased demand for nitrogen during grain filling. This detailed characterization of the transcriptional regulation of dhurrin biosynthesis, bioactivation and remobilization genes during organ and plant development will aid elucidation of gene regulatory networks and signalling pathways that modulate gene expression and dhurrin levels. In-depth knowledge of dhurrin metabolism could improve the yield, nitrogen use efficiency and stress resilience of Sorghum.
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Affiliation(s)
- Roslyn M Gleadow
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Brian A McKinley
- Department of Plant Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | | | - Austin C Lamb
- Department of Plant Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Birger Lindberg Møller
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - John E Mullet
- Department of Plant Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
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Dantas LLB, Dourado MM, de Lima NO, Cavaçana N, Nishiyama MY, Souza GM, Carneiro MS, Caldana C, Hotta CT. Field microenvironments regulate crop diel transcript and metabolite rhythms. THE NEW PHYTOLOGIST 2021; 232:1738-1749. [PMID: 34312886 DOI: 10.1111/nph.17650] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Most research in plant chronobiology has been done in laboratory conditions. However, laboratories usually fail to mimic natural conditions and their slight fluctuations, highlighting or obfuscating rhythmicity. High-density crops, such as sugarcane (Saccharum hybrid), generate field microenvironments with specific light and temperature regimes resulting from mutual shading. We measured the metabolic and transcriptional rhythms in the leaves of 4-month-old (4 mo) and 9 mo field-grown sugarcane. Most of the assayed rhythms in 9 mo sugarcane peaked >1 h later than in 4 mo sugarcane, including rhythms of the circadian clock gene, LATE ELONGATED HYPOCOTYL (LHY). We hypothesized that older sugarcane perceives dawn later than younger sugarcane as a consequence of self-shading. As a test, we measured LHY rhythms in plants on the east and the west sides of a field. We also tested if a wooden wall built between lines of sugarcane plants changed their rhythms. The LHY peak was delayed in the plants in the west of the field or beyond the wall; both shaded at dawn. We conclude that plants in the same field may have different phases resulting from field microenvironments, impacting important agronomical traits, such as flowering time, stalk weight and number.
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Affiliation(s)
- Luíza Lane Barros Dantas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Maíra Marins Dourado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Natalia Oliveira de Lima
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Natale Cavaçana
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Milton Yutaka Nishiyama
- Laboratório Especial de Toxicologia Aplicada, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Glaucia Mendes Souza
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Monalisa Sampaio Carneiro
- Departamento de Biotecnologia e Produção Vegetal e Animal, Centro de Ciências Agrárias, Universidade Federal de São Carlos, São Carlos, SP, 13600-970, Brazil
| | - Camila Caldana
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Carlos Takeshi Hotta
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, 05508-000, Brazil
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Phytochrome A elevates plant circadian-clock components to suppress shade avoidance in deep-canopy shade. Proc Natl Acad Sci U S A 2021; 118:2108176118. [PMID: 34187900 DOI: 10.1073/pnas.2108176118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Shade-avoiding plants can detect the presence of neighboring vegetation and evoke escape responses before canopy cover limits photosynthesis. Rapid stem elongation facilitates light foraging and enables plants to overtop competitors. A major regulator of this response is the phytochrome B photoreceptor, which becomes inactivated in light environments with a low ratio of red to far-red light (low R:FR), characteristic of vegetational shade. Although shade avoidance can provide plants with a competitive advantage in fast-growing stands, excessive stem elongation can be detrimental to plant survival. As such, plants have evolved multiple feedback mechanisms to attenuate shade-avoidance signaling. The very low R:FR and reduced levels of photosynthetically active radiation (PAR) present in deep canopy shade can, together, trigger phytochrome A (phyA) signaling, inhibiting shade avoidance and promoting plant survival when resources are severely limited. The molecular mechanisms underlying this response have not been fully elucidated. Here, we show that Arabidopsis thaliana phyA elevates early-evening expression of the central circadian-clock components TIMING OF CAB EXPRESSION 1 (TOC1), PSEUDO RESPONSE REGULATOR 7 (PRR7), EARLY FLOWERING 3 (ELF3), and ELF4 in photocycles of low R:FR and low PAR. These collectively suppress stem elongation, antagonizing shade avoidance in deep canopy shade.
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