Plant Physiol |南京农大生科院沈文飚课题组揭示氢气通过靶向硝酸还原酶正向调控硝酸吸收和种子大小

尽管植物中分子氢(H2)合成的途径仍有待完全阐明,但大量证据表明植物产生的H2可以调节发育和应激反应。这里,我们提供了遗传和分子证据,提示硝酸还原酶(NR)可能是H2感应的靶点,通过正向调控氮素利用效率(NUE)和种子大小在拟南芥(Arabidopsis thaliana)中发挥作用。在对照和特别是在低氮供应下,NR的表达水平和NUE的变化与外源添加的H2或通过遗传操作产生的内源H2呈正相关。H2改善的硝酸同化也是通过NR去磷酸化实现的。

NR突变影响了H2对种子大小的调控。进一步的遗传学证据表明,H2、NR和一氧化氮可以协同调节对N营养匮乏条件下的硝酸同化反应。

总的来说,我们的数据表明NR可能是H2感应的靶点,最终正向调节硝酸摄取和种子大小。这些结果对H2信号及其在植物代谢中的功能提供了见解。

关键词:分子氢;硝酸同化;硝酸还原酶;一氧化氮;氮素利用效率;种子大小

Abstract

Although the sources of molecular hydrogen (H2) synthesis in plants remain to be fully elucidated, ample evidence shows that plant-based H2 can regulate development and stress responses. Here, we present genetic and molecular evidence indicating that nitrate reductase (NR) might be a target of H2 sensing that positively regulates nitrogen use efficiency (NUE) and seed size in Arabidopsis (Arabidopsis thaliana). The expression level of NR and changes of NUE under control and, in particular, low nitrogen supply, were positively associated with H2 addition supplied exogenously or through genetic manipulation. The improvement in nitrate assimilation achieved by H2 was also mediated via NR dephosphorylation. H2 control of seed size was impaired by NR mutation. Further genetic evidence revealed that H2, NR, and nitric oxide can synergistically regulate nitrate assimilation in response to N starvation conditions. Collectively, our data indicate that NR might be a target for H2 sensing, ultimately positively regulating nitrate uptake and seed size. These results provide insights into H2 signaling and its functions in plant metabolism.

来源：

https://academic.oup.com/plphys/advance-article-abstract/doi/10.1093/plphys/kiad474/7251441

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