Ethylene regulates auxin-mediated root gravitropic machinery and controls root angle in cereal crops
Ethylene regulates auxin-mediated root gravitropic machinery and controls root angle in cereal crops
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DOI：
10.1093/plphys/kiae134
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发表时间：
2024-03-06
期刊：
影响因子：
7.4
通讯作者：
Huang，Guoqiang
中科院分区：
文献类型：
--
作者：
Kong，Xiuzhen;Xiong，Yali;Huang，Guoqiang
根角是优化不同土壤深度必需资源获取的关键因素。根角的调节依赖于生长素介导的根向倾斜机制。虽然乙烯对生长素水平的影响是已知的，但其在控制根向地性和角度方面的具体作用仍不确定，特别是当拟南芥（拟南芥）核心乙烯信号突变体没有显示向地性缺陷时。我们以水稻（Oryza sativaL.）和玉米（Zea mays .）为研究对象，清楚地揭示了乙烯通过调节生长素的生物合成和根向地机制参与谷物作物的根角调节。阐明了乙烯调控植物生长素生物合成以控制根系向地性机制的分子机制。与野生型相比，乙烯不敏感突变体sesein2 （esein2）和eseil1 （eseil1）的冠根角明显较浅。向地性试验显示，这些突变体的根向地性反应降低。激素谱分析证实，theosein2突变体的根尖生长素水平下降，外源生长素（NAA）恢复了这两个乙烯不敏感突变体的根向地性。此外，生长素合成突变体茅紫10(mhz10)/色氨酸氨基转移酶2（ostar2）的向地性反应和浅冠根角表型均受损。同样，玉米乙烯不敏感突变体（zmein2）也表现出倾斜性和根角表型的缺陷。综上所述，我们的研究表明，在水稻和玉米中，乙烯控制生长素依赖的根向倾斜机制来调节根角，揭示了拟南芥和谷类作物在乙烯信号传导方面的功能差异。这些发现有助于更好地理解根角调控，并对改善农业系统中的资源获取具有重要意义。
Root angle is a critical factor in optimizing the acquisition of essential resources from different soil depths. The regulation of root angle relies on the auxin-mediated root gravitropism machinery. While the influence of ethylene on auxin levels is known, its specific role in governing root gravitropism and angle remains uncertain, particularly when Arabidopsis (Arabidopsis thaliana) core ethylene signaling mutants show no gravitropic defects. Our research, focusing on rice (Oryza sativaL.) and maize (Zea mays), clearly reveals the involvement of ethylene in root angle regulation in cereal crops through the modulation of auxin biosynthesis and the root gravitropism machinery. We elucidated the molecular components by which ethylene exerts its regulatory effect on auxin biosynthesis to control root gravitropism machinery. The ethylene-insensitive mutantsethylene insensitive2(osein2) andethylene insensitive like1(oseil1), exhibited substantially shallower crown root angle compared to the wild type. Gravitropism assays revealed reduced root gravitropic response in these mutants. Hormone profiling analysis confirmed decreased auxin levels in the root tips of theosein2mutant, and exogenous auxin (NAA) application rescued root gravitropism in both ethylene-insensitive mutants. Additionally, the auxin biosynthetic mutantmao hu zi10(mhz10)/tryptophan aminotransferase2(ostar2) showed impaired gravitropic response and shallow crown root angle phenotypes. Similarly, maize ethylene-insensitive mutants (zmein2) exhibited defective gravitropism and root angle phenotypes. In conclusion, our study highlights that ethylene controls the auxin-dependent root gravitropism machinery to regulate root angle in rice and maize, revealing a functional divergence in ethylene signaling betweenArabidopsisand cereal crops. These findings contribute to a better understanding of root angle regulation and have implications for improving resource acquisition in agricultural systems.