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Barros J, Shrestha HK, Serrani-Yarce JC, Engle NL, Abraham PE, Tschaplinski TJ, Hettich RL, Dixon RA. Proteomic and metabolic disturbances in lignin-modified Brachypodium distachyon. Plant Cell 2022; 34:3339-3363. [PMID: 35670759 PMCID: PMC9421481 DOI: 10.1093/plcell/koac171] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/23/2022] [Indexed: 05/30/2023]
Abstract
Lignin biosynthesis begins with the deamination of phenylalanine and tyrosine (Tyr) as a key branch point between primary and secondary metabolism in land plants. Here, we used a systems biology approach to investigate the global metabolic responses to lignin pathway perturbations in the model grass Brachypodium distachyon. We identified the lignin biosynthetic protein families and found that ammonia-lyases (ALs) are among the most abundant proteins in lignifying tissues in grasses. Integrated metabolomic and proteomic data support a link between lignin biosynthesis and primary metabolism mediated by the ammonia released from ALs that is recycled for the synthesis of amino acids via glutamine. RNA interference knockdown of lignin genes confirmed that the route of the canonical pathway using shikimate ester intermediates is not essential for lignin formation in Brachypodium, and there is an alternative pathway from Tyr via sinapic acid for the synthesis of syringyl lignin involving yet uncharacterized enzymatic steps. Our findings support a model in which plant ALs play a central role in coordinating the allocation of carbon for lignin synthesis and the nitrogen available for plant growth. Collectively, these data also emphasize the value of integrative multiomic analyses to advance our understanding of plant metabolism.
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Affiliation(s)
| | - Him K Shrestha
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Genome Science and Technology, University of Tennessee, Knoxville, Tennessee 37916, USA
| | - Juan C Serrani-Yarce
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76201, USA
| | - Nancy L Engle
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76201, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - Paul E Abraham
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - Timothy J Tschaplinski
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - Robert L Hettich
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
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