NMT历史上的今天丨Plant Physiol：TaNAC2-5A调控硝酸盐提升小麦产量

2015年12月27日，中科院遗传发育所童依平、何雪用NMT在Plant Physiology上发表了标题为The Nitrate-Inducible NAC Transcription Factor TaNAC2-5A Controls Nitrate Response and Increases Wheat Yield的研究成果。

期刊：Plant Physiology

主题：TaNAC2-5A控制硝酸盐反应提高小麦产量

标题：The Nitrate-Inducible NAC Transcription Factor TaNAC2-5A Controls Nitrate Response and Increases Wheat Yield

影响因子：7.394

检测指标：NO3-流速

作者：中科院遗传发育所童依平、何雪

Nitrate is a major nitrogen resource for cereal  crops; thus, understanding nitrate signaling in cereal crops is valuable  for engineering crops with improved nitrogen use efficiency. Although  several regulators have been identified in nitrate sensing and signaling  in Arabidopsis (Arabidopsis thaliana), the equivalent information in  cereals is missing.

Here, we isolated a nitrate-inducible and  cereal-specific NAM, ATAF, and CUC (NAC) transcription factor,  TaNAC2-5A, from wheat (Triticum aestivum). A chromatin  immunoprecipitation assay showed that TaNAC2-5A could directly bind to  the promoter regions of the genes encoding nitrate transporter and  glutamine synthetase. Overexpression of TaNAC2-5A in wheat enhanced root  growth and nitrate influx rate and, hence, increased the root’s ability  to acquire nitrogen. Furthermore, we found that  TaNAC2-5A-overexpressing transgenic wheat lines had higher grain yield  and higher nitrogen accumulation in aerial parts and allocated more  nitrogen in grains in a field experiment.

These results suggest  that TaNAC2-5A is involved in nitrate signaling and show that it is an  exciting gene resource for breeding crops with more efficient use of  fertilizer.

中文摘要（谷歌机翻）

硝酸盐是谷物作物的主要氮资源。因此，了解谷类作物中的硝酸盐信号对于提高氮素利用效率的工程作物非常有价值。尽管已经在拟南芥（Arabidopsis thaliana）的硝酸盐感测和信号传导中确定了几种调节剂，但谷物中的等效信息却缺失了。

在这里，我们从小麦（Triticum   aestivum）中分离出了硝酸盐诱导型和谷类特异性NAM，ATAF和CUC（NAC）转录因子TaNAC2-5A。染色质免疫沉淀分析表明，TaNAC2-5A可以直接结合到编码硝酸盐转运蛋白和谷氨酰胺合成酶的基因的启动子区域。TaNAC2-5A在小麦中的过表达增强了根系的生长和硝酸盐的流入速率，因此增加了根系获得氮的能力。此外，我们发现在田间试验中，过表达TaNAC2-5A的转基因小麦品系具有较高的籽粒产量和较高的氮素在地上部分的积累，并在籽粒中分配了更多的氮。

这些结果表明，TaNAC2-5A参与硝酸盐信号传导，并表明它是利用更有效地使用肥料来育种作物的令人兴奋的基因资源。

D and E, Nitrate influx rates at the root tip surface  (D) and expression levels of nitrate transporters in whole seedlings  (E). Seedlings were grown for 4 d on solid medium that contained 6 mM  nitrate. The roots were used to measure nitrate flux rate in the  measuring solution that contained 1 mM nitrate. Data are means 6 SE for  six plants. Whole seedlings were used to analyze the expression of  nitrate trans-porters. The relative expression levels were normalized to  the expression of AtACTIN2 (AtACT2). Data are means 6 SE of three  replicates. Asterisks indicate that the difference between the means of  the wild type and the transgenic lines was significant at the P , 0.05  (*) and P , 0.01 (**) levels.