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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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Powell AE, Heyl A. The origin and early evolution of cytokinin signaling. FRONTIERS IN PLANT SCIENCE 2023; 14:1142748. [PMID: 37457338 PMCID: PMC10338860 DOI: 10.3389/fpls.2023.1142748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 05/23/2023] [Indexed: 07/18/2023]
Abstract
Angiosperms, especially Arabidopsis and rice, have long been at the center of plant research. However, technological advances in sequencing have led to a dramatic increase in genome and transcriptome data availability across land plants and, more recently, among green algae. These data allowed for an in-depth study of the evolution of different protein families - including those involved in the metabolism and signaling of phytohormones. While most early studies on phytohormone evolution were phylogenetic, those studies have started to be complemented by genetic and biochemical studies in recent years. Examples of such functional analyses focused on ethylene, jasmonic acid, abscisic acid, and auxin. These data have been summarized recently. In this review, we will focus on the progress in our understanding of cytokinin biology. We will use these data to synthesize key points about the evolution of cytokinin metabolism and signaling, which might apply to the evolution of other phytohormones as well.
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3
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Gao XR, Zhang H, Li X, Bai YW, Peng K, Wang Z, Dai ZR, Bian XF, Zhang Q, Jia LC, Li Y, Liu QC, Zhai H, Gao SP, Zhao N, He SZ. The B-box transcription factor IbBBX29 regulates leaf development and flavonoid biosynthesis in sweet potato. PLANT PHYSIOLOGY 2023; 191:496-514. [PMID: 36377782 PMCID: PMC9806656 DOI: 10.1093/plphys/kiac516] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/23/2022] [Indexed: 06/01/2023]
Abstract
Plant flavonoids are valuable natural antioxidants. Sweet potato (Ipomoea batatas) leaves are rich in flavonoids, regenerate rapidly, and can adapt to harsh environments, making them an ideal material for flavonoid biofortification. Here, we demonstrate that the B-box (BBX) family transcription factor IbBBX29 regulates the flavonoid contents and development of sweet potato leaves. IbBBX29 was highly expressed in sweet potato leaves and significantly induced by auxin (IAA). Overexpression of IbBBX29 contributed to a 21.37%-70.94% increase in leaf biomass, a 12.08%-21.85% increase in IAA levels, and a 31.33%-63.03% increase in flavonoid accumulation in sweet potato, whereas silencing this gene produced opposite effects. Heterologous expression of IbBBX29 in Arabidopsis (Arabidopsis thaliana) led to a dwarfed phenotype, along with enhanced IAA and flavonoid accumulation. RNA-seq analysis revealed that IbBBX29 modulates the expression of genes involved in the IAA signaling and flavonoid biosynthesis pathways. Chromatin immunoprecipitation-quantitative polymerase chain reaction and electrophoretic mobility shift assay indicated that IbBBX29 targets key genes of IAA signaling and flavonoid biosynthesis to activate their expression by binding to specific T/G-boxes in their promoters, especially those adjacent to the transcription start site. Moreover, IbBBX29 physically interacted with developmental and phenylpropanoid biosynthesis-related proteins, such as AGAMOUS-LIKE 21 protein IbAGL21 and MYB308-like protein IbMYB308L. Finally, overexpressing IbBBX29 also increased flavonoid contents in sweet potato storage roots. These findings indicate that IbBBX29 plays a pivotal role in regulating IAA-mediated leaf development and flavonoid biosynthesis in sweet potato and Arabidopsis, providing a candidate gene for flavonoid biofortification in plants.
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Affiliation(s)
- Xiao-ru Gao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Huan Zhang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- Sanya Institute of China Agricultural University, Hainan 572025, China
| | - Xu Li
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- Sanya Institute of China Agricultural University, Hainan 572025, China
| | - Yi-wei Bai
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Kui Peng
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Zhen Wang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Zhuo-ru Dai
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Xiao-feng Bian
- Provincial Key Laboratory of Agrobiology, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210000, China
| | - Qian Zhang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- Provincial Key Laboratory of Agrobiology, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210000, China
| | - Li-cong Jia
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- Institute of Grain and Oil Crops, Yantai Academy of Agricultural Sciences, Yantai 265500, China
| | - Yan Li
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China
| | - Qing-chang Liu
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Hong Zhai
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Shao-pei Gao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Ning Zhao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Shao-zhen He
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
- Sanya Institute of China Agricultural University, Hainan 572025, China
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Chen L, Jameson GB, Guo Y, Song J, Jameson PE. The LONELY GUY gene family: from mosses to wheat, the key to the formation of active cytokinins in plants. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:625-645. [PMID: 35108444 PMCID: PMC8989509 DOI: 10.1111/pbi.13783] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 05/19/2023]
Abstract
LONELY GUY (LOG) was first identified in a screen of rice mutants with defects in meristem maintenance. In plants, LOG codes for cytokinin riboside 5'-monophosphate phosphoribohydrolase, which converts inactive cytokinin nucleotides directly to the active free bases. Many enzymes with the PGGxGTxxE motif have been misannotated as lysine decarboxylases; conversely not all enzymes containing this motif are cytokinin-specific LOGs. As LOG mutants clearly impact yield in rice, we investigated the LOG gene family in bread wheat. By interrogating the wheat (Triticum aestivum) genome database, we show that wheat has multiple LOGs. The close alignment of TaLOG1, TaLOG2 and TaLOG6 with the X-ray structures of two functional Arabidopsis thaliana LOGs allows us to infer that the wheat LOGs 1-11 are functional LOGs. Using RNA-seq data sets, we assessed TaLOG expression across 70 tissue types, their responses to various stressors, the pattern of cis-regulatory elements (CREs) and intron/exon patterns. TaLOG gene family members are expressed variously across tissue types. When the TaLOG CREs are compared with those of the cytokinin dehydrogenases (CKX) and glucosyltransferases (CGT), there is close alignment of CREs between TaLOGs and TaCKXs reflecting the key role of CKX in maintaining cytokinin homeostasis. However, we suggest that the main homeostatic mechanism controlling cytokinin levels in response to biotic and abiotic challenge resides in the CGTs, rather than LOG or CKX. However, LOG transgenics and identified mutants in rice variously impact yield, providing interesting avenues for investigation in wheat.
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Affiliation(s)
- Lei Chen
- School of Life SciencesYantai UniversityYantaiChina
| | | | - Yichu Guo
- School of Life SciencesYantai UniversityYantaiChina
| | - Jiancheng Song
- School of Life SciencesYantai UniversityYantaiChina
- Yantai Jien Biological Science & Technology LtdYEDAYantaiChina
| | - Paula E. Jameson
- School of Life SciencesYantai UniversityYantaiChina
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
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5
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Liu D, Zhao H, Xiao Y, Zhang G, Cao S, Yin W, Qian Y, Yin Y, Zhang J, Chen S, Chu C, Tong H. A cryptic inhibitor of cytokinin phosphorelay controls rice grain size. MOLECULAR PLANT 2022; 15:293-307. [PMID: 34562665 DOI: 10.1016/j.molp.2021.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/21/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Plant hormone cytokinin signals through histidine-aspartic acid (H-D) phosphorelay to regulate plant growth and development. While it is well known that the phosphorelay involves histidine kinases, histidine phosphotransfer proteins (HPs), and response regulators (RRs), how this process is regulated by external components remains unknown. Here we demonstrate that protein phosphatase with kelch-like domains (PPKL1), known as a signaling component of steroid hormone brassinosteroid, is actually a cryptic inhibitor of cytokinin phosphorelay in rice (Oryza sativa). Mutation at a specific amino acid D364 of PPKL1 activates cytokinin response and thus enlarges grain size in a semi-dominant mutant named s48. Overexpression of PPKL1 containing D364, either with the deletion of the phosphatase domain or not, rescues the s48 mutant phenotype. PPKL1 interacts with OsAHP2, one of authentic HPs, and D364 resides in a region resembling the receiver domain of RRs. Accordingly, PPKL1 can utilize D364 to suppress OsAHP2-to-RR phosphorelay, whereas mutation of D364 abolishes the effect. This function of PPKL1 is independent of the phosphatase domain that is required for brassinosteroid signaling. Importantly, editing of the D364-residential region produces a diversity of semi-dominant mutations associated with variously increased grain sizes. Further screening of the edited plants enables the identification of two genotypes that confer significantly improved grain yield. Collectively, our study uncovers a noncanonical cytokinin signaling suppressor and provides a robust tool for seed rational design.
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Affiliation(s)
- Dapu Liu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - He Zhao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yunhua Xiao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Guoxia Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Shouyun Cao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenchao Yin
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yangwen Qian
- Biogle Genome Editing Center, Changzhou, Jiangsu Province 213125, China
| | - Yanhai Yin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Jinsong Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Shouyi Chen
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Chengcai Chu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Hongning Tong
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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