Roots exhibit hydrotropism in response to moisture gradients, with the hydrotropism-related gene () playing a role in regulating root hydrotropism in an oblique orientation. However, the mechanisms underlying MIZ1-regulated root hydrotropism are not well understood. In this study, we employed obliquely oriented experimental systems to investigate root hydrotropism in . We found that the mutant displays reduced root hydrotropism but increased root gravitropism following hydrostimulation, as compared to wild-type plants. Conversely, overexpression of AtMIZ1 leads to enhanced root hydrotropism but decreased root gravitropism following hydrostimulation, as compared to wild-type plants. Using co-immunoprecipitation followed by mass spectrometry (IP-MS), we explored proteins that interact with AtMIZ1, and we identified PGMC1 co-immunoprecipitated with MIZ1 . Furthermore, the mutant exhibited higher expression of the gene and increased phosphoglucomutase (PGM) activity, while AtMIZ1 overexpressors resulted in lower expression of the gene, reduced amyloplast amount, and reduced PGM activity in comparison to wild-type roots. In addition, different natural accessions having difference in their hydrotropic response demonstrated expression level of was negatively correlated with hydrotropic root curvature and expression. Our results provide valuable insights into the role of amyloplast in MIZ1-regulated root hydrotropism.

中文翻译：

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淀粉体参与 MIZ1 调节的根向水性

根部表现出响应湿度梯度的向水性，与向水性相关的基因（）在调节根向斜方向的向水性方面发挥作用。然而，MIZ1 调节根向水性的机制尚不清楚。在这项研究中，我们采用倾斜实验系统来研究根向水性。我们发现，与野生型植物相比，突变体在水刺激后表现出根向水性降低，但根向地性增加。相反，与野生型植物相比，AtMIZ1 的过度表达导致根向水性增强，但水刺激后根向地性降低。使用免疫共沉淀和质谱 (IP-MS)，我们探索了与 AtMIZ1 相互作用的蛋白质，并鉴定了与 MIZ1 免疫共沉淀的 PGMC1。此外，与野生型根相比，突变体表现出更高的基因表达和增加的磷酸葡萄糖变位酶（PGM）活性，而AtMIZ1过表达导致基因表达降低、淀粉体量减少和PGM活性降低。此外，不同的天然种质在其亲水性反应方面存在差异，表明 的表达水平与亲水性根曲率和表达呈负相关。我们的结果为淀粉体在 MIZ1 调节的根向水性中的作用提供了有价值的见解。