Maize ZmMYB59 inhibits post-germinative shoot and root elongation through ZmGA2ox3/10-mediated gibberellin catabolism.

Qinghui Han; Xiaomin Wang; Mengyuan Yan; Zan Ren; Kaihui Zhai; Hubo Li; Chujun Huang; Yang Wang; Thomas L&#xfc;bberstedt; Guangwu Zhao

doi:10.1111/nph.71500

PubMed · 42563137

Maize ZmMYB59 inhibits post-germinative shoot and root elongation through ZmGA2ox3/10-mediated gibberellin catabolism.

Qinghui Han·Xiaomin Wang·Mengyuan Yan·Zan Ren·Kaihui Zhai·Hubo Li·Chujun Huang·Yang Wang·Thomas Lübberstedt·Guangwu Zhao

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Abstract

Gibberellin (GA) promotes seed germination, but sustained or excessive GA signaling after germination can lead to aberrant root and shoot elongation. How GA homeostasis is transcriptionally restrained during post-germinative seedling development remains unclear. Using overexpression and gene-edited maize materials, we demonstrate that ZmMYB59 inhibits root and shoot elongation during post-germinative growth. Integrated RNA-Seq and CUT&Tag analyses identified the GA catabolism genes ZmGA2ox3 and ZmGA2ox10 as candidate direct targets of ZmMYB59. Hormone profiling analysis showed elevated bioactive GA1 and GA4 levels in the scutellum and aleurone layer cells of zmmyb59 mutants. Dual-luciferase assays, electrophoretic mobility shift assays, and ChIP-qPCR further confirmed that ZmMYB59 directly binds AC8 cis-elements in the ZmGA2ox3/10 promoters and activates their transcription. The zmga2ox3/10 double mutant, but neither single mutant, exhibited enhanced root and shoot elongation, accompanied by GA4 accumulation. This phenotype was suppressed by exogenous application of the GA biosynthesis inhibitor uniconazole. Transcriptomic and biochemical analyses further revealed enhanced starch degradation, reduced starch content, and increased soluble sugar accumulation in the double mutant. Taken together, these findings reveal that the ZmMYB59-ZmGA2ox3/10 module restrains GA accumulation and starch mobilization after germination, thereby coordinating reserve utilization with post-germinative root and shoot growth in maize.

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Gibberellins Zea mays Plant Shoots Germination Plant Proteins Gene Expression Regulation, Plant Plant Roots Mutation Promoter Regions, Genetic MYB transcription factor gibberellin maize root elongation shoot elongation Journal Article

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Qinghui Han, Xiaomin Wang, Mengyuan Yan, Zan Ren, Kaihui Zhai, Hubo Li, Chujun Huang, Yang Wang, Thomas Lübberstedt, Guangwu Zhao. 2026-08-06. Maize ZmMYB59 inhibits post-germinative shoot and root elongation through ZmGA2ox3/10-mediated gibberellin catabolism.. https://doi.org/10.1111/nph.71500

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