低氮胁迫对高羊茅IAA生长素代谢组影响的研究

氮是植物生长发育必须的大量元素之一,增施氮肥虽然有利于植物产量的提高,但是不利于土壤的可持续利用。牧草类作物相对于其他农作物受贫瘠土壤胁迫的危害更加严重,然而相应的理论研究还比较滞后。本文以禾本科牧草资源高羊茅为研究对象,利用LC-ESI-MS(液相色谱电离串联质谱)分析了正常和低氮条件下高羊茅叶片中的代谢组分,两种材料中分别稳定检测到1424和1251种代谢产物,利用OPLS-DA(正交偏最小二乘法判别分析)分析方法,鉴别到低氮处理后主要有13种代谢物质的含量发生变化,其中包括了生长素IAA。利用荧光定量PCR的方法检测8个IAA信号途径相关基因的表达,发现其表达在低氮处理后均被诱导,另外通过测定IAA激素的含量,也证实了IAA在高羊茅缺氮处理后升高这一事实。本研究为高羊茅氮缺乏的分子机理提供了重要的线索,也为在生产中通过喷施IAA来缓解植物应对氮缺乏的措施提供了理论依据。

Auxin signaling pathways respond to low-nitrogen stress as revealed by metabolomic profiling analysis in tall fescue

Nitrogen is indispensable for plant growth and development.We can increase yield in many crops u-sing nitrogen application,however,excessive application of nitrogen fertilizer is uneconomic and harmful to the environment.Forages generally suffer more severe nutrition stress than other crops.In this study,metabolites were analyzed with LC-ESI-MS (liquid chromatography-electrospray ionization-mass spectrometry)in tall fes-cue leaves under normal and low-nitrogen stress conditions.A total of 1424 and 1251 metabolites were detected in the two groups respectively using OPLS-DA (orthogonal partial least squares discriminant analysis).Thir-teen major metabolites were identified through a search of public databases,including auxin (indole acetic acid, IAA).Eight genes related to auxin signaling were up-regulated by nitrogen stress,detected using quantitative real-time PCR (qRT-PCR).The IAA concentration was elevated in tall fescue leaves after nitrogen stress, detected by enzyme-linked immuno sorbent assay (ELISA).Our research provides valuable information for studying the mechanisms of the response of tall fescue to low nitrogen.The results suggest that application of IAA could be used to alleviate the harmful effects of nitrogen deficiency.