高油酸花生(Arachishypogaea L.)油具有优异的营养成分和热氧化稳定性,有利于人体健康和工业生产。但是高油酸花生在发芽期间对温度比较敏感,限制了其在低温地区的引种。为了进一步了解高油酸花生在发芽期响应低温胁迫的分子机制,本研究选用田间试验中耐寒表现不同的4种高油酸花生品种,分析其在发芽期低温胁迫下的全基因组水平调控。通过转录组高通量测序共获得139 429条Unigene,其中两组耐寒与不耐寒高油酸花生品种在低温胁迫下共产生差异表达基因(differentially expressed gene, DEG) 3520个,且耐寒花生中上调表达的DEG数目大于下调表达的数目。GO分析表明,耐寒高油酸花生中有关细胞膜代谢与完整性以及细胞外周蛋白差异表达基因的数量较多;KEGG通路分析表明,植物病原相互作用和植物激素信号转导通路在抗寒中起着重要作用。进一步筛选出4个低温诱导蛋白基因——时钟调控蛋白基因(TIC) 、AGO4蛋白基因(AGO4)、组蛋白-赖氨酸N甲基类转移酶ATX3基因(ATX3)、FERONIA类受体蛋白激酶基因(FER)和3个转录因子基因——bHLH、3R-1MYB和EREB,采用qRT-PCR检测这些基因在低温胁迫下的表达量。结果显示,在低温处理3 h后TIC、ATX3和AGO4以及转录因子基因bHLH、MYB和EREB的表达量明显升高,FER在胁迫12 h后也有明显升高,表明这些基因在花生萌发期响应低温胁迫。本研究为深入了解高油酸花生发芽期低温胁迫转录调控机制和筛选花生抗寒基因提供了数据资源。

High oleic (HO) peanut (Arachishypogaea L.) oils benefit human health and industrial production due to its superior nutritional composition and thermo-oxidative stability. However, HO peanut is sensitive to cold stress especially during germination, which limits its distribution in low temperature areas. To understand the molecular mechanism of cold responses in HO peanuts at germination stage, four HO peanut varieties with different cold tolerance were selected in field experiments to analyze their genome-wide gene regulation under low temperatures. High-throughput sequencing and transcriptome analysis revealed a total of 139 429 unigenes. Among these, 3520 common differentially expressed genes (DEG) were detected between two groups of cold-tolerant and cold-sensitive peanuts, and the number of up-regulated genes was greater than that of down-regulated genes in the cold-tolerant peanuts. Gene ontology analysis indicates that the number of DEGs involved in cell membrane metabolism and integrity as well as proteins located in the cell periphery were significantly higher in the cold-tolerant peanuts. KEGG pathway analysis suggests that plant-pathogen interaction and plant hormone signal transduction pathway play important roles in cold tolerance. Four cold-induced genes, TIC(TIME FOR COFFEE), ATX3(histone-lysine N-methyltransferase ATX3-like), AGO4(argonaute 4-like), FER(FERONIA-like receptor protein kinase), and three transcription factor genes, bHLH(bHLH49-like transcription factor), MYB(MYB-related protein 3R-1-like)and EREB(Ethylene-responsive element binding factor 6)were selected to verify the expression profile via real-time quantitative PCR detection. The expression of TIC, ATX3, AGO4, bHLH, MYB and EREB significantly increased within 3 hours after low temperature stress, while the expression of FER significantlyincreased after 12 hours, suggesting that these genes responded to low temperature stress during peanut germination. This work not only sheds light on the transcriptional regulation of HO peanut under low-temperature stress during germination but also provides data resources for screening candidate genes in improving peanuts stress resistance.