硝态氮素对辣椒幼苗应答盐胁迫的蛋白质组分析

Proteomic Analysis of Nitrate Nitrogen Response to Salt Stress in Pepper Seedlings

为探讨硝态氮素盐胁迫对辣椒幼苗差异表达蛋白的影响,本研究对水培硝态氮素辣椒幼苗进行盐胁迫处理,以期从蛋白质水平上揭示硝态氮素辣椒幼苗适应盐胁迫的分子机制。采用蛋白质非标记定量技术(label-free)结合液相色谱与串联质谱(LC-MS/MS)定量蛋白质组技术,鉴定和分析硝态氮素辣椒叶片响应盐胁迫的差异表达蛋白。结果表明,鉴定出定量蛋白4 697个,显著差异表达蛋白质132个(变化倍数≥1.5, P≤0.05),其中88个上调表达蛋白,44个蛋白下调表达;将差异蛋白与GO、KOG等数据库进行比对,分析硝态氮素盐胁迫下差异蛋白的功能,发现分类差异蛋白主要参与代谢、细胞过程、应激等生物学进程。其中,KEGG显著富集的通路(P<0.05)集中在过氧物酶体、氮代谢、脂肪酸降解、不饱和脂肪酸的4个代谢通路中;STRING蛋白质互作网络差异蛋白涉及代谢、无机离子的转运和分子伴侣等蛋白质,且谷氨酸合酶、糖基转移酶、钠/氢交换体、热休克蛋白同源物70 kD可能在硝态氮素缓解耐盐调控过程中发挥重要作用。本研究为深入认识硝态氮素缓解盐胁迫的应答分子调控机制提供理论依据。

In order to explore the effect of nitrate-nitrogen salt stress on the differentially expressed proteins of pepper seedlings, this study conducted salt stress treatment on hydroponic nitrate-nitrogen pepper seedlings, expect to reveal the nitrate-nitrogen pepper seedlings adapting to salt stress mechanism from the protein level. Using protein-free quantitative technology(label-free) combined with liquid chromatography and tandem mass spectrometry(LC-MS/MS) quantitative proteomics technology, the differentially expressed proteins of nitrate nitrogen pepper leaves in response to salt stress were identified and analyzed. The results showed that 4 697 quantitative proteins were identified and 132 proteins were significantly differentially expressed(Fold change≥1.5, P≤0.05), of which 88 were up-regulated and 44 were down-regulated;the differential protein was compared with GO, KOG and other databases, analyzing the functions of differential proteins under the stress of nitrate nitrogen salt, it is found that differential proteins are mainly involved in biological processes such as metabolism, cellular processes, and stress.Among them, the significantly enriched pathways of KEGG(P<0.05) are concentrated in the four metabolic pathways of peroxisomes, nitrogen metabolism, fatty acid degradation, and unsaturated fatty acids;STRING protein interaction network differential proteins involve metabolism, inorganic ions proteins such as transport and molecular chaperones, glycosyltransferase, sodium/hydrogen exchanger, and heat shock protein homologue 70 kD may play an important role in the regulation of salt tolerance by nitrate nitrogen. This study provides a theoretical basis for in-depth understanding of the molecular regulation mechanism of nitrate nitrogen in alleviating salt stress.