The miR164a-NAM3 module confers cold tolerance by inducing ethylene production in tomato

第一作者：Dong Yufei

第一单位：浙江大学

通讯作者：Yanhong Zhou

 Abstarct 

背景回顾：Due to the high sensitivity to cold, the yield and quality of tomato (Solanum lycopersicumL.) are severely restricted by cold stress. The NAC transcription factor (TF) family has been characterized as an important player in plant growth, development, and stress response, but the role of NAC TFs in cold stress and their interaction with other post-transcriptional regulators such as microRNAs in cold tolerance remain elusive. 

由于对低温的高度敏感性，导致番茄的产量和果实品质受到低温胁迫的严重限制。NAC转录因子家族在植物的生长、发育以及胁迫响应过程中扮演着重要作用；但是其在番茄低温胁迫以及其在低温抗性中会和诸如microRNAs等的哪些转录后调控因子相互作用，这一问题还不清楚。

结果1-SlNAM3过表达表型：Here, we demonstrated that SlNAM3, the predicted target of Sl-miR164a/b-5p, improved cold tolerance as evidenced by a higher maximum quantum efficiency of photosystem II (Fv/Fm), lower relative electrolyte leakage (REL) and less wilting in SlNAM3-overexpression plants than wild-type. 

本文中，作者揭示了番茄中Sl-miR164a/b-5p的靶基因SlNAM3能够提升番茄的低温耐受性，具体表现为SlNAM3过表达植株会比野生型在低温处理下具有更高的光系统II最大光化学量子效率（Fv/Fm）、更低的相对电解质渗漏（REL）以及更少的萎蔫。

结果2-SlNAM3上游Sl-miR164a/b-5p：Further genetic and molecular confirmation revealed that Sl-miR164a/b-5p functioned upstream of SlNAM3 by inhibiting the expression of the latter, thus playing a negative role in cold tolerance. 

进一步的遗传和分子实验证明，Sl-miR164a/b-5p作用于SlNAM3基因的上游，通过抑制后者基因的表达，从而在番茄的低温抗性中发挥负面作用。

结果3-Sl-miR164a/b-5p-SlNAM3模块促进乙烯合成：Interestingly, this role is partially mediated by an ethylene-dependent pathway, as either Sl-miR164a/b-5p silencing or SlNAM3 overexpression improved cold tolerance in the transgenic lines by promoting ethylene production. Moreover, silencing the ethylene synthesis genes, SlACS1A, SlACS1B, SlACO1, and SlACO4, resulted in a significant decrease in cold tolerance. Further experiments demonstrated that NAM3 activates SlACS1A, SlACS1B, SlACO1, and SlACO4 transcription by directly binding to their promoters. 

有趣的是，该过程部分由依赖于乙烯的途径所介导，因为无论是Sl-miR164a/b-5p沉默或是SlNAM3过表达都能够通过促进乙烯的产生，提高转基因株系的低温抗性。此外，沉默SlACS1A、SlACS1B、SlACO1以及SlACO4等乙烯通路上的基因，会导致低温耐受性的显著减弱。进一步的实验表明，NAM3能够直接结合到SlACS1A、SlACS1B、SlACO1以及SlACO4基因启动子并激活这些基因的表达。

结论：Taken together, our study identified the miR164a-NAM3 module conferring cold tolerance in tomato plants via the direct regulation of SlACS1A, SlACS1B, SlACO1, and SlACO4 expression to induce ethylene synthesis.

miR164a-NAM3模块能够通过直接调控乙烯合成基因的表达，促进乙烯的生物合成，从而提升番茄的低温耐受性。

** 周艳虹 **

doi: https://doi.org/10.1111/tpj.15807

Journal: the plant journal

First Published: May 15, 2022

CITE

Yufei Dong, Mingjia Tang, Zelan Huang, Jianing Song, Jin Xu, Golam Jalal Ahammed, Jingquan Yu, Yanhong Zhou. The miR164a-NAM3 module confers cold tolerance by inducing ethylene production in tomato. the plant journal, 2022. DOI: https://doi.org/10.1111/tpj.15807