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Argueso CT, Kieber JJ. Cytokinin: From autoclaved DNA to two-component signaling. THE PLANT CELL 2024; 36:1429-1450. [PMID: 38163638 PMCID: PMC11062471 DOI: 10.1093/plcell/koad327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 01/03/2024]
Abstract
Since its first identification in the 1950s as a regulator of cell division, cytokinin has been linked to many physiological processes in plants, spanning growth and development and various responses to the environment. Studies from the last two and one-half decades have revealed the pathways underlying the biosynthesis and metabolism of cytokinin and have elucidated the mechanisms of its perception and signaling, which reflects an ancient signaling system evolved from two-component elements in bacteria. Mutants in the genes encoding elements involved in these processes have helped refine our understanding of cytokinin functions in plants. Further, recent advances have provided insight into the mechanisms of intracellular and long-distance cytokinin transport and the identification of several proteins that operate downstream of cytokinin signaling. Here, we review these processes through a historical lens, providing an overview of cytokinin metabolism, transport, signaling, and functions in higher plants.
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Affiliation(s)
- Cristiana T Argueso
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Joseph J Kieber
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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2
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Blyth HR, Smith D, King R, Bayon C, Ashfield T, Walpole H, Venter E, Ray RV, Kanyuka K, Rudd JJ. Fungal plant pathogen "mutagenomics" reveals tagged and untagged mutations in Zymoseptoria tritici and identifies SSK2 as key morphogenesis and stress-responsive virulence factor. FRONTIERS IN PLANT SCIENCE 2023; 14:1140824. [PMID: 37206970 PMCID: PMC10190600 DOI: 10.3389/fpls.2023.1140824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/29/2023] [Indexed: 05/21/2023]
Abstract
"Mutagenomics" is the combination of random mutagenesis, phenotypic screening, and whole-genome re-sequencing to uncover all tagged and untagged mutations linked with phenotypic changes in an organism. In this study, we performed a mutagenomics screen on the wheat pathogenic fungus Zymoseptoria tritici for altered morphogenetic switching and stress sensitivity phenotypes using Agrobacterium-mediated "random" T-DNA mutagenesis (ATMT). Biological screening identified four mutants which were strongly reduced in virulence on wheat. Whole genome re-sequencing defined the positions of the T-DNA insertion events and revealed several unlinked mutations potentially affecting gene functions. Remarkably, two independent reduced virulence mutant strains, with similarly altered stress sensitivities and aberrant hyphal growth phenotypes, were found to have a distinct loss of function mutations in the ZtSSK2 MAPKKK gene. One mutant strain had a direct T-DNA insertion affecting the predicted protein's N-terminus, while the other possessed an unlinked frameshift mutation towards the C-terminus. We used genetic complementation to restore both strains' wild-type (WT) function (virulence, morphogenesis, and stress response). We demonstrated that ZtSSK2 has a non-redundant function with ZtSTE11 in virulence through the biochemical activation of the stress-activated HOG1 MAPK pathway. Moreover, we present data suggesting that SSK2 has a unique role in activating this pathway in response to specific stresses. Finally, dual RNAseq-based transcriptome profiling of WT and SSK2 mutant strains revealed many HOG1-dependent transcriptional changes in the fungus during early infection and suggested that the host response does not discriminate between WT and mutant strains during this early phase. Together these data define new genes implicated in the virulence of the pathogen and emphasise the importance of a whole genome sequencing step in mutagenomic discovery pipelines.
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Affiliation(s)
- Hannah R. Blyth
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Dan Smith
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Robert King
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Carlos Bayon
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Tom Ashfield
- Crop Health and Protection (CHAP), Rothamsted Research, Harpenden, United Kingdom
| | - Hannah Walpole
- Bioimaging Unit, Rothamsted Research, Harpenden, United Kingdom
| | - Eudri Venter
- Bioimaging Unit, Rothamsted Research, Harpenden, United Kingdom
| | - Rumiana V. Ray
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, United Kingdom
| | - Kostya Kanyuka
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Jason J. Rudd
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
- *Correspondence: Jason J. Rudd,
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Rosignoli S, Cosenza F, Moscou MJ, Civolani L, Musiani F, Forestan C, Milner SG, Savojardo C, Tuberosa R, Salvi S. Cloning the barley nec3 disease lesion mimic mutant using complementation by sequencing. THE PLANT GENOME 2022; 15:e20187. [PMID: 35302294 DOI: 10.1002/tpg2.20187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
Disease lesion mimic (DLM) or necrotic mutants display necrotic lesions in the absence of pathogen infections. They can show improved resistance to some pathogens and their molecular dissection can contribute to revealing components of plant defense pathways. Although forward-genetics strategies to find genes causal to mutant phenotypes are available in crops, these strategies require the production of experimental cross populations, mutagenesis, or gene editing and are time- and resource-consuming or may have to deal with regulated plant materials. In this study, we described a collection of 34 DLM mutants in barley (Hordeum vulgare L.) and applied a novel method called complementation by sequencing (CBS), which enables the identification of the gene responsible for a mutant phenotype given the availability of two or more chemically mutagenized individuals showing the same phenotype. Complementation by sequencing relies on the feasibility to obtain all induced mutations present in chemical mutants and on the low probability that different individuals share the same mutated genes. By CBS, we identified a cytochrome P450 CYP71P1 gene as responsible for orange blotch DLM mutants, including the historical barley nec3 locus. By comparative phylogenetic analysis we showed that CYP71P1 gene family emerged early in angiosperm evolution but has been recurrently lost in some lineages including Arabidopsis thaliana (L.) Heynh. Complementation by sequencing is a straightforward cost-effective approach to clone genes controlling phenotypes in a chemically mutagenized collection. The TILLMore (TM) collection will be instrumental for understanding the molecular basis of DLM phenotypes and to contribute knowledge about mechanisms of host-pathogen interaction.
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Affiliation(s)
- Serena Rosignoli
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
| | - Francesco Cosenza
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
- The Sainsbury Laboratory, Univ. of East Anglia, Norwich Research Park, Norwich, NR4 7UK, UK
| | - Matthew J Moscou
- The Sainsbury Laboratory, Univ. of East Anglia, Norwich Research Park, Norwich, NR4 7UK, UK
| | - Laura Civolani
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Dep. of Pharmacy and Biotechnology, Univ. of Bologna, Via Belmeloro 6, Bologna, Italy, 40126
| | - Cristian Forestan
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
| | - Sara Giulia Milner
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Seeland, D
| | - Castrense Savojardo
- Biocomputing Group, Dep. of Pharmacy and Biotechnology, Univ. of Bologna, Via Belmeloro 6, Bologna, Italy, 40126
| | - Roberto Tuberosa
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
| | - Silvio Salvi
- Dep. of Agricultural and Food Sciences, Univ. of Bologna, Viale G. Fanin 44, Bologna, Italy, 40127
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Anders S, Cowling W, Pareek A, Gupta KJ, Singla-Pareek SL, Foyer CH. Gaining Acceptance of Novel Plant Breeding Technologies. TRENDS IN PLANT SCIENCE 2021; 26:575-587. [PMID: 33893048 DOI: 10.1016/j.tplants.2021.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/10/2021] [Accepted: 03/11/2021] [Indexed: 05/28/2023]
Abstract
Ensuring the sustainability of agriculture under climate change has led to a surge in alternative strategies for crop improvement. Advances in integrated crop breeding, social acceptance, and farm-level adoption are crucial to address future challenges to food security. Societal acceptance can be slow when consumers do not see the need for innovation or immediate benefits. We consider how best to address the issue of social licence and harmonised governance for novel gene technologies in plant breeding. In addition, we highlight optimised breeding strategies that will enable long-term genetic gains to be achieved. Promoted by harmonised global policy change, innovative plant breeding can realise high and sustainable productivity together with enhanced nutritional traits.
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Affiliation(s)
- Sven Anders
- Department of Resource Economics and Environmental Sociology, University of Alberta, Edmonton, AB T6G 2H1, Canada
| | - Wallace Cowling
- The UWA Institute of Agriculture and UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Ashwani Pareek
- The UWA Institute of Agriculture and UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia 6009, Australia; Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | | | - Sneh L Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Christine H Foyer
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, UK.
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Mukherjee A. Mutagenomics: The Future of Genetic Screens. PLANT PHYSIOLOGY 2020; 184:1616-1617. [PMID: 33277326 PMCID: PMC7723118 DOI: 10.1104/pp.20.01455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
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