1. Soybean symbiotic-nodule zonation and cell differentiation are defined by NIN2 signaling and GH3-dependent auxin homeostasis.
- Author
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Tu T, Gao Z, Li L, Chen J, Ye K, Xu T, Mai S, Han Q, Chen C, Wu S, Dong Y, Chen J, Huang L, Guan Y, Xie F, and Chen X
- Subjects
- Transcription Factors metabolism, Transcription Factors genetics, Nitrogen Fixation, Glycine max metabolism, Glycine max genetics, Glycine max growth & development, Cell Differentiation, Indoleacetic Acids metabolism, Root Nodules, Plant metabolism, Root Nodules, Plant growth & development, Homeostasis, Signal Transduction, Gene Expression Regulation, Plant, Symbiosis, Plant Proteins metabolism, Plant Proteins genetics
- Abstract
Symbiotic nodules comprise two classes, indeterminate and determinate, defined by the presence/absence of apical meristem and developmental zonation. Why meristem and zonation are absent from determinate nodules remains unclear. Here, we define cell types in developing soybean nodules, highlighting the undifferentiated infection zones and differentiated nitrogen-fixation zones. Auxin governs infection zone maintenance. GRETCHEN HAGEN 3 (GH3) enzymes deactivate auxin by conjugation and promote cell differentiation. gh3 mutants increased undifferentiated cells and enlarged infection zones. The central symbiosis-transcription factor NIN2a activates GH3.1 to reduce auxin levels and facilitates cell differentiation. High auxin promotes NIN2a protein accumulation and enhances signaling, further deactivating auxin and depleting infection zones. Our findings shed light on the NIN2a-GH3-auxin module that drives soybean nodule cell differentiation. This study challenges our understanding of determinate nodule development and proposes that the regulation of nodule zonation offers valuable insights into broader mechanisms of cell differentiation across plant species., Competing Interests: Declaration of interests Patents entitled “Soybean auxin conjugating enzyme GRETCHEN HAGEN 3 (GH3) gene family and their applications (202410456123.X)” have been applied for in China. X.C., T.T., Z.G., L.H., and J.C. are listed as inventors., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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