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Zhong J, van Esse GW, Bi X, Lan T, Walla A, Sang Q, Franzen R, von Korff M. INTERMEDIUM-M encodes an HvAP2L-H5 ortholog and is required for inflorescence indeterminacy and spikelet determinacy in barley. Proc Natl Acad Sci U S A 2021; 118:e2011779118. [PMID: 33593903 DOI: 10.1073/pnas.2011779118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meristem determinacy/indeterminacy influences flower number and seed production in crops. Two closely related cool-season cereals, barley and wheat, produce variable and defined numbers of spikelets in their inflorescences, respectively. In this study, we identify a series of allelic barley mutants named intermedium-m and double seed1 that develop wheat-like determinate inflorescences producing a terminal spikelet and a reduced number of spikelets. INT-M/DUB1 is an APETALA2-like transcription factor that promotes an active inflorescence meristem via suppression of spikelet initiation and the maintenance of meristem identity. Our work has identified key regulators that may prolong meristem activities and could be genetically engineered in barley, wheat, and other cereals to improve grain yield. Inflorescence architecture dictates the number of flowers and, ultimately, seeds. The architectural discrepancies between two related cereals, barley and wheat, are controlled by differences in determinacy of inflorescence and spikelet meristems. Here, we characterize two allelic series of mutations named intermedium-m (int-m) and double seed1 (dub1) that convert barley indeterminate inflorescences into wheat-like determinate inflorescences bearing a multifloreted terminal spikelet and spikelets with additional florets. INT-M/DUB1 encodes an APETALA2-like transcription factor (HvAP2L-H5) that suppresses ectopic and precocious spikelet initiation signals and maintains meristem activity. HvAP2L-H5 inhibits the identity shift of an inflorescence meristem (IM) to a terminal spikelet meristem (TSM) in barley. Null mutations in AP2L-5 lead to fewer spikelets per inflorescence but extra florets per spikelet. In wheat, prolonged and elevated AP2L-A5 activity in rAP2L-A5 mutants delays but does not suppress the IM−TSM transition. We hypothesize that the regulation of AP2L-5 orthologs and downstream genes contributes to the different inflorescence determinacy in barley and wheat. We show that AP2L-5 proteins are evolutionarily conserved in grasses, promote IM activity, and restrict floret number per spikelet. This study provides insights into the regulation of spikelet and floret number, and hence grain yield in barley and wheat.
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Munns R, Day DA, Fricke W, Watt M, Arsova B, Barkla BJ, Bose J, Byrt CS, Chen ZH, Foster KJ, Gilliham M, Henderson SW, Jenkins CLD, Kronzucker HJ, Miklavcic SJ, Plett D, Roy SJ, Shabala S, Shelden MC, Soole KL, Taylor NL, Tester M, Wege S, Wegner LH, Tyerman SD. Energy costs of salt tolerance in crop plants. New Phytol 2020; 225:1072-1090. [PMID: 31004496 DOI: 10.1111/nph.15864] [Citation(s) in RCA: 166] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/25/2019] [Indexed: 05/21/2023]
Abstract
Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H+ -ATPase also is a critical component. One proposed leak, that of Na+ influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na+ and Cl- concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components.
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Affiliation(s)
- Rana Munns
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin (UCD), Dublin, 4, Ireland
| | - Michelle Watt
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Borjana Arsova
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2481, Australia
| | - Jayakumar Bose
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Caitlin S Byrt
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Zhong-Hua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Matthew Gilliham
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Sam W Henderson
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Urrbrae, SA, 5064, Australia
| | - Colin L D Jenkins
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Darren Plett
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stuart J Roy
- Australian Research Council (ARC) Industrial Transformation Research Hub for Wheat in a Hot and Dry Climate, School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Sergey Shabala
- Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, Tas., 7001, Australia
- International Centre for Environmental Membrane Biology, Foshan University, Foshan, 528000, China
| | - Megan C Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Kathleen L Soole
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Nicolas L Taylor
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Molecular Sciences and Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Mark Tester
- Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Stefanie Wege
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Lars H Wegner
- Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology (IHM), D-76344, Eggenstein-Leopoldshafen, Germany
| | - Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
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