Ethylene Inhibits Root Elongation during Alkaline Stress through AUXIN1 and Associated Changes in Auxin Accumulation
Ethylene Inhibits Root Elongation during Alkaline Stress through AUXIN1 and Associated Changes in Auxin Accumulation
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DOI：
10.1104/pp.15.00523
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发表时间：
2015-08-01
期刊：
影响因子：
7.4
通讯作者：
Lu, Ying-Tang
中科院分区：
文献类型：
--
作者：
Li, Juan;Xu, Heng-Hao;Lu, Ying-Tang
土壤碱性导致全世界农作物产量和质量的大幅下降。植物根是最先感受土壤碱度的器官，这导致了较短的初生根。然而，碱性胁迫介导的根伸长抑制的机制仍有待进一步阐明。在这里，我们报告说，碱性条件下抑制拟南芥（拟南芥）幼苗的主根伸长，通过减少细胞分裂潜力的分生组织区和乙烯信号影响这一进程。乙烯感受性拮抗剂银（Ag+）缓解了碱胁迫对根伸长的抑制。此外，乙烯信号突变体乙烯响应1 -3（etr 1 -3），乙烯不敏感2（ein 2），和ein 3 -1在碱性条件下表现出较少的根长减少，表明对碱度的敏感性降低。乙烯生物合成也被发现在碱性胁迫介导的根抑制中发挥作用;乙烯overproducer 1 -1突变体，由于1-氨基环丙烷-1-羧酸合成酶5的稳定性增加而过量产生乙烯，对碱性胁迫过敏。此外，乙烯生物合成抑制剂钴（Co2+）抑制碱性胁迫介导的抑制根伸长。我们进一步发现，碱性胁迫引起生长素水平的增加，促进生长素生物合成相关基因的表达，但生长素水平的增加减少在根的etr 1 -3和ein 3 -1突变体和Ag+/Co 2+处理的野生型植物。其他遗传和生理数据表明，AUXIN 1（AUX 1）参与碱性胁迫介导的根伸长抑制。两者合计，我们的研究结果表明，乙烯调节碱性胁迫介导的抑制根生长，通过刺激AUX 1和生长素生物合成相关基因的表达，增加生长素的积累。
Soil alkalinity causes major reductions in yield and quality of crops worldwide. The plant root is the first organ sensing soil alkalinity, which results in shorter primary roots. However, the mechanism underlying alkaline stress-mediated inhibition of root elongation remains to be further elucidated. Here, we report that alkaline conditions inhibit primary root elongation of Arabidopsis (Arabidopsis thaliana) seedlings by reducing cell division potential in the meristem zones and that ethylene signaling affects this process. The ethylene perception antagonist silver (Ag+) alleviated the inhibition of root elongation by alkaline stress. Moreover, the ethylene signaling mutants ethylene response1-3 (etr1-3), ethylene insensitive2 (ein2), and ein3-1 showed less reduction in root length under alkaline conditions, indicating a reduced sensitivity to alkalinity. Ethylene biosynthesis also was found to play a role in alkaline stress-mediated root inhibition; the ethylene overproducer1-1 mutant, which overproduces ethylene because of increased stability of 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID SYNTHASE5, was hypersensitive to alkaline stress. In addition, the ethylene biosynthesis inhibitor cobalt (Co2+) suppressed alkaline stress-mediated inhibition of root elongation. We further found that alkaline stress caused an increase in auxin levels by promoting expression of auxin biosynthesis-related genes, but the increase in auxin levels was reduced in the roots of the etr1-3 and ein3-1 mutants and in Ag+/Co2+-treated wild-type plants. Additional genetic and physiological data showed that AUXIN1 (AUX1) was involved in alkaline stress-mediated inhibition of root elongation. Taken together, our results reveal that ethylene modulates alkaline stress-mediated inhibition of root growth by increasing auxin accumulation by stimulating the expression of AUX1 and auxin biosynthesis-related genes.