表油菜素内酯影响水稻幼苗响应低温胁迫的蛋白质组学分析

表油菜素内酯(2,4-Epibrassinolide,EBR)是一种被广泛研究和应用的油菜素内酯类(brassinosteroids,BRs)植物生长调节剂,它能有效增强植物对低温的耐受性,但EBR在蛋白质组水平上对水稻幼苗响应低温胁迫的影响尚不清楚。本研究用0.1 mg L–1 EBR和蒸馏水分别浸泡萌发的日本晴种子,然后提取4°C胁迫培养和26°C正常培养幼苗的总蛋白,进行质谱非标(label-free)定量分析和平行反应监测(parallel reaction monitoring,PRM)验证。最终共鉴定出5778个蛋白质,其中,在有定量信息的4834个蛋白中,401个上调和220个下调蛋白与EBR影响水稻幼苗响应低温胁迫有关。功能分析和代谢通路富集分析发现,上调蛋白主要与RNA结合或水解酶活性等分子功能相关,并富集在碳代谢、叶酸合成和氨基酸生物合成等途径中;下调蛋白主要与催化活性和氧化还原酶活性相关,主要涉及卟啉和叶绿素代谢等代谢途径。PRM验证结果和文献证据显示,分布在碳代谢和苯丙素代谢通路中的NADP-苹果酸酶、过氧化物酶、3-磷酸甘油酸脱氢酶、烯醇化酶、甘油醛-3-磷酸脱氢酶和丙酮酸激酶参与了EBR对低温胁迫水稻幼苗的调控,提示BRs可通过多种途径影响水稻幼苗对低温胁迫的响应。

Proteomic Analysis of the Effect of 2,4-Epibrassinolide on Rice Seedlings Response to Cold Stress

As a plant growth regulator which functionally resembles a kind of plant hormone Brassinosteroids (BRs), 2,4-Epibrassinolide (EBR) has been widely studied and applied in different aspects. EBR can enhance plant’s cold tolerance effectively, but the proteomic characteristics of the effect of EBR on rice seedings response to cold stress are still unclear. In this study, the germinating seeds of rice Nipponbare were treated with 0.1 mg L ^-1 EBR and distilled water before they were cultivated at 4°C or 26°C, and then the total protein of each group of seedlings was extracted. Finally, proteomes of rice seedings were analyzed by label-free quantitative mass spectrometry, and some important proteins were verified by parallel reaction monitoring technique (PRM). A total of 5778 protein groups were identified by qualitative method and 4834 protein groups were accurately quantitated. Among them, 401 up-regulated and 220 down-regulated proteins were related to the effect of EBR on rice seedings response to cold stress. The up-regulated proteins were mainly related to molecular function of RNA binding and hydrolase activity, and mainly enriched in the pathways of carbon metabolism, folic acid synthesis and amino acid biosynthesis. The down-regulated proteins were mainly related to catalytic activity and oxidoreductase activity, and mainly enriched in the pathways of porphyrin and chlorophyll metabolism and other metabolic pathways. PRM validation and literature analysis showed that NADP-malic acidase, peroxidase, 3-phosphoglycerate dehydrogenase, enolase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase, which are distributed in the pathways of carbon metabolism and phenylpropanol metabolism and others, take part in the regulation of EBR on rice seedlings response to cold stress, suggesting that BRs can affect rice seedlings response to cold stress through a variety of pathways.