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Taleski M, Jin M, Chapman K, Taylor K, Winning C, Frank M, Imin N, Djordjevic MA. CEP hormones at the nexus of nutrient acquisition and allocation, root development, and plant-microbe interactions. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:538-552. [PMID: 37946363 PMCID: PMC10773996 DOI: 10.1093/jxb/erad444] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023]
Abstract
A growing understanding is emerging of the roles of peptide hormones in local and long-distance signalling that coordinates plant growth and development as well as responses to the environment. C-TERMINALLY ENCODED PEPTIDE (CEP) signalling triggered by its interaction with CEP RECEPTOR 1 (CEPR1) is known to play roles in systemic nitrogen (N) demand signalling, legume nodulation, and root system architecture. Recent research provides further insight into how CEP signalling operates, which involves diverse downstream targets and interactions with other hormone pathways. Additionally, there is emerging evidence of CEP signalling playing roles in N allocation, root responses to carbon levels, the uptake of other soil nutrients such as phosphorus and sulfur, root responses to arbuscular mycorrhizal fungi, plant immunity, and reproductive development. These findings suggest that CEP signalling more broadly coordinates growth across the whole plant in response to diverse environmental cues. Moreover, CEP signalling and function appear to be conserved in angiosperms. We review recent advances in CEP biology with a focus on soil nutrient uptake, root system architecture and organogenesis, and roles in plant-microbe interactions. Furthermore, we address knowledge gaps and future directions in this research field.
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Affiliation(s)
- Michael Taleski
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Marvin Jin
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Kelly Chapman
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Katia Taylor
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Courtney Winning
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Manuel Frank
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Nijat Imin
- School of Science, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - Michael A Djordjevic
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
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Chapman K, Taleski M, Frank M, Djordjevic MA. C-TERMINALLY ENCODED PEPTIDE (CEP) and cytokinin hormone signaling intersect to promote shallow lateral root angles. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:631-641. [PMID: 37688302 DOI: 10.1093/jxb/erad353] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/07/2023] [Indexed: 09/10/2023]
Abstract
Root system architecture (RSA) influences the acquisition of heterogeneously dispersed soil nutrients. Cytokinin and C-TERMINALLY ENCODED PEPTIDE (CEP) hormones affect RSA, in part by controlling the angle of lateral root (LR) growth. Both hormone pathways converge on CEP DOWNSTREAM 1 (CEPD1) and CEPD2 to control primary root growth; however, a role for CEPDs in controlling the growth angle of LRs is unknown. Using phenotyping combined with genetic and grafting approaches, we show that CEP hormone-mediated shallower LR growth requires cytokinin biosynthesis and perception in roots via ARABIDOPSIS HISTIDINE KINASE 2 (AHK2) and AHK3. Consistently, cytokinin biosynthesis and ahk2,3 mutants phenocopied the steeper root phenotype of cep receptor 1 (cepr1) mutants on agar plates, and CEPR1 was required for trans-Zeatin (tZ)-type cytokinin-mediated shallower LR growth. In addition, the cepd1,2 mutant was less sensitive to CEP and tZ, and showed basally steeper LRs on agar plates. Cytokinin and CEP pathway mutants were grown in rhizoboxes to define the role of these pathways in controlling RSA. Only cytokinin receptor mutants and cepd1,2 partially phenocopied the steeper-rooted phenotype of cepr1 mutants. These results show that CEP and cytokinin signaling intersect to promote shallower LR growth, but additional components contribute to the cepr1 phenotype in soil.
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Affiliation(s)
- Kelly Chapman
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Michael Taleski
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
| | - Manuel Frank
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Michael A Djordjevic
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, 2601Australia
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Taleski M, Chapman K, Novák O, Schmülling T, Frank M, Djordjevic MA. CEP peptide and cytokinin pathways converge on CEPD glutaredoxins to inhibit root growth. Nat Commun 2023; 14:1683. [PMID: 36973257 PMCID: PMC10042822 DOI: 10.1038/s41467-023-37282-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 03/07/2023] [Indexed: 03/29/2023] Open
Abstract
AbstractC-TERMINALLY ENCODED PEPTIDE (CEP) and cytokinin hormones act over short and long distances to control plant responses to environmental cues. CEP and cytokinin pathway mutants share phenotypes, however, it is not known if these pathways intersect. We show that CEP and cytokinin signalling converge on CEP DOWNSTREAM (CEPD) glutaredoxins to inhibit primary root growth. CEP inhibition of root growth was impaired in mutants defective in trans-zeatin (tZ)-type cytokinin biosynthesis, transport, perception, and output. Concordantly, mutants affected in CEP RECEPTOR 1 showed reduced root growth inhibition in response to tZ, and altered levels of tZ-type cytokinins. Grafting and organ-specific hormone treatments showed that tZ-mediated root growth inhibition involved CEPD activity in roots. By contrast, root growth inhibition by CEP depended on shoot CEPD function. The results demonstrate that CEP and cytokinin pathways intersect, and utilise signalling circuits in separate organs involving common glutaredoxin genes to coordinate root growth.
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Ivanovici A, Laffont C, Larrainzar E, Patel N, Winning CS, Lee HC, Imin N, Frugier F, Djordjevic MA. The Medicago SymCEP7 hormone increases nodule number via shoots without compromising lateral root number. PLANT PHYSIOLOGY 2023; 191:2012-2026. [PMID: 36653329 PMCID: PMC10022606 DOI: 10.1093/plphys/kiad012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Legumes acquire soil nutrients through nitrogen-fixing root nodules and lateral roots. To balance the costs and benefits of nodulation, legumes negatively control root nodule number by autoregulatory and hormonal pathways. How legumes simultaneously coordinate root nodule and lateral root development to procure nutrients remains poorly understood. In Medicago (Medicago truncatula), a subset of mature C-TERMINALLY ENCODED PEPTIDE (CEP) hormones can systemically promote nodule number, but all CEP hormones tested to date negatively regulate lateral root number. Here we showed that Medicago CEP7 produces a mature peptide, SymCEP7, that promotes nodulation from the shoot without compromising lateral root number. Rhizobial inoculation induced CEP7 in the susceptible root nodulation zone in a Nod factor-dependent manner, and, in contrast to other CEP genes, its transcription level was elevated in the ethylene signaling mutant sickle. Using mass spectrometry, fluorescence microscopy and expression analysis, we demonstrated that SymCEP7 activity requires the COMPACT ROOT ARCHITECTURE 2 receptor and activates the shoot-to-root systemic effector, miR2111. Shoot-applied SymCEP7 rapidly promoted nodule number in the pM to nM range at concentrations up to five orders of magnitude lower than effects mediated by root-applied SymCEP7. Shoot-applied SymCEP7 also promoted nodule number in White Clover (Trifolium repens) and Lotus (Lotus japonicus), which suggests that this biological function may be evolutionarily conserved. We propose that SymCEP7 acts in the Medicago shoot to counter balance the autoregulation pathways induced rapidly by rhizobia to enable nodulation without compromising lateral root growth, thus promoting the acquisition of nutrients other than nitrogen to support their growth.
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Affiliation(s)
- Ariel Ivanovici
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Carole Laffont
- University of Paris-Saclay, CNRS, INRAE, University Paris-Cité, Univ. d’Evry, Gif-sur-Yvette, France
| | - Estíbaliz Larrainzar
- Sciences Department, Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Pamplona 31006, Spain
| | - Neha Patel
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Courtney S Winning
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Han-Chung Lee
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Nijat Imin
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
- School of Science, Western Sydney University, Penrith, New South Wales 2751, Australia
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland, New Zealand
| | - Florian Frugier
- University of Paris-Saclay, CNRS, INRAE, University Paris-Cité, Univ. d’Evry, Gif-sur-Yvette, France
| | - Michael A Djordjevic
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
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Luo Z, Wang J, Li F, Lu Y, Fang Z, Fu M, Mysore KS, Wen J, Gong J, Murray JD, Xie F. The small peptide CEP1 and the NIN-like protein NLP1 regulate NRT2.1 to mediate root nodule formation across nitrate concentrations. THE PLANT CELL 2023; 35:776-794. [PMID: 36440970 PMCID: PMC9940871 DOI: 10.1093/plcell/koac340] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/24/2022] [Accepted: 11/24/2022] [Indexed: 05/12/2023]
Abstract
Legumes acquire fixed nitrogen (N) from the soil and through endosymbiotic association with diazotrophic bacteria. However, establishing and maintaining N2-fixing nodules are expensive for the host plant, relative to taking up N from the soil. Therefore, plants suppress symbiosis when N is plentiful and enhance symbiosis when N is sparse. Here, we show that the nitrate transporter MtNRT2.1 is required for optimal nodule establishment in Medicago truncatula under low-nitrate conditions and the repression of nodulation under high-nitrate conditions. The NIN-like protein (NLP) MtNLP1 is required for MtNRT2.1 expression and regulation of nitrate uptake/transport under low- and high-nitrate conditions. Under low nitrate, the gene encoding the C-terminally encoded peptide (CEP) MtCEP1 was more highly expressed, and the exogenous application of MtCEP1 systemically promoted MtNRT2.1 expression in a compact root architecture 2 (MtCRA2)-dependent manner. The enhancement of nodulation by MtCEP1 and nitrate uptake were both impaired in the Mtnrt2.1 mutant under low nitrate. Our study demonstrates that nitrate uptake by MtNRT2.1 differentially affects nodulation at low- and high-nitrate conditions through the actions of MtCEP1 and MtNLP1.
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Affiliation(s)
- Zhenpeng Luo
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jiang Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Fuyu Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yuting Lu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zijun Fang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Mengdi Fu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Kirankumar S Mysore
- Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - Jiangqi Wen
- Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - Jiming Gong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jeremy D Murray
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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Roy S, Müller LM. A rulebook for peptide control of legume-microbe endosymbioses. TRENDS IN PLANT SCIENCE 2022; 27:870-889. [PMID: 35246381 DOI: 10.1016/j.tplants.2022.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Plants engage in mutually beneficial relationships with microbes, such as arbuscular mycorrhizal fungi or nitrogen-fixing rhizobia, for optimized nutrient acquisition. In return, the microbial symbionts receive photosynthetic carbon from the plant. Both symbioses are regulated by the plant nutrient status, indicating the existence of signaling pathways that allow the host to fine-tune its interactions with the beneficial microbes depending on its nutrient requirements. Peptide hormones coordinate a plethora of developmental and physiological processes and, recently, various peptide families have gained special attention as systemic and local regulators of plant-microbe interactions and nutrient homeostasis. In this review, we identify five 'rules' or guiding principles that govern peptide function during symbiotic plant-microbe interactions, and highlight possible points of integration with nutrient acquisition pathways.
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Affiliation(s)
- Sonali Roy
- College of Agriculture, Tennessee State University, Nashville, TN 37209, USA.
| | - Lena Maria Müller
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA.
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