02442nam a2200337Ia 4500 MX-MdCICY 20260521091803.0 CICY B-4258 A nitrogen-responsive cytokinin oxidase/dehydrogenase regulates root response to high ammonium in rice New Phytologist, https://doi.org/10.1111/nph.20128, 2024 Artículo Plant root system is significantly influenced by high soil levels of ammonium nitrogen, leading to reduced root elongation and enhanced lateral root branching. In Arabidopsis, these processes have been reported to be mediated by phytohormones and their downstream signaling pathways, while the controlling mechanisms remain elusive in crops. Through a transcriptome analysis of roots subjected to high/low ammonium treatments, we identified a cytokinin oxidase/dehydrogenase encoding gene, CKX3, whose expression is induced by high ammonium. Knocking out CKX3 and its homologue CKX8 results in shorter seminal roots, fewer lateral roots, and reduced sensitivity to high ammonium. Endogenous cytokinin levels are elevated by high ammonium or in ckx3 mutants. Cytokinin application results in shorter seminal roots and fewer lateral roots in wild-type, mimicking the root responses of ckx3 mutants to high ammonium. Furthermore, CKX3 is transcriptionally activated by type-B RR25 and RR26, and ckx3 mutants have reduced auxin content and signaling in roots under low ammonium. This study identified RR25/26-CKX3-cytokinin as a signal module that mediates root responses to external ammonium by modulating of auxin signaling in the root meristem and lateral root primordium. This highlights the critical role of cytokinin metabolism in regulating rice root development in response to ammonium. © 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation. AMMONIUM AUXIN CKX CYTOKININ LATERAL ROOT RICE SEMINAL ROOT Li, L. Jia, L. Duan, X. Lv, Y. Ye, C. Ding, C. Xuan, W. A. https://drive.google.com/file/d/1WUpx1-xgZ_7C7_ivDf_Y6Egd6zq9oKb-/view?usp=drive_link Para ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx Loc REF1 250602s9999 xx |||||s2 |||| ||und|d 31442 31442 0 0 Loc 0 0 F1 CICY CICY RE 2025-06-26 0 B-4258 2025-06-26 08:09:24 2025-06-26 REF1