Physiological and transcriptomic analyses reveal the molecular networks of responses induced by exogenous trehalose in plant
Physiological and transcriptomic analyses reveal the molecular networks of responses induced by exogenous trehalose in plant
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生理和转录组分析揭示了植物中外源海藻糖诱导的反应分子网络
DOI：
10.1371/journal.pone.0217204
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发表时间：
2019-05-22
期刊：
影响因子：
3.7
通讯作者：
Yu, Haidong
中科院分区：
文献类型：
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作者：
Shi, Yongchun;Sun, Hui;Yu, Haidong
众所周知，外源海藻糖能够提高植物对一些非生物和生物胁迫的抗性。然而，关于烟草叶片对海藻糖处理的分子响应相关信息却十分有限。在此，我们发现外源海藻糖在处理2小时后，能迅速减小烟草叶片气孔开度，上调NADPH氧化酶基因表达，并增加叶片中超氧阴离子（O₂·⁻ ）和过氧化氢（H₂O₂ ）的含量。我们进一步证明，NADPH氧化酶抑制剂咪唑和二苯基碘鎓（DPI）能够促进经海藻糖处理的烟草叶片气孔开度的恢复。外源海藻糖以浓度依赖的方式显著增强了烟草叶片对烟草花叶病的抗性。为阐明烟草对海藻糖的分子响应机制，我们通过RNA测序技术，研究了分别用10 mM（低浓度）或50 mM（高浓度）海藻糖处理2小时或24小时后烟草叶片的转录组响应。与对照相比，在不同海藻糖处理条件下共发现1288个差异表达基因（DEGs）。其中，1075个（83.5%）差异表达基因是由低浓度（10 mM）海藻糖诱导产生的，这表明低浓度海藻糖是一种更有效的诱导剂。京都基因与基因组百科全书（KEGG）通路分析的功能注释显示，这些差异表达基因涉及代谢途径、次生代谢产物的生物合成、植物激素信号转导、植物 - 病原体相互作用、内质网中的蛋白质加工、类黄酮合成以及昼夜节律等。由所有处理条件下调控的核心差异表达基因生成的蛋白质 - 蛋白质相互作用网络显著揭示，包括ClpB1、热休克蛋白70（HSP70）、DnaJB1样蛋白、通用应激蛋白（USP）A样蛋白、两个FTSH6蛋白、肌醇半乳糖苷合酶1（GolS1）样蛋白和叶绿体热休克蛋白在内的8种蛋白质，在烟草叶片对外源海藻糖的响应中发挥核心作用。我们的数据表明，海藻糖触发了一条涉及钙和活性氧（ROS）介导的信号转导通路。这些核心成分可能使烟草对非生物和生物胁迫产生部分抗性或耐受性。此外，我们选取了19个差异表达基因进行实时荧光定量聚合酶链反应（qRT-PCR）分析。这19个候选基因的qRT-PCR结果与RNA测序分析鉴定出的差异表达基因相符，证实了我们RNA测序数据的可靠性。
It is well known that exogenous trehalose can improve resistances of plants to some abiotic and biotic stresses. Nonetheless, information respecting the molecular responses of tobacco leaves to Tre treatment is limited. Here we show that exogenous Tre can rapidly reduce stomatal aperture, up-regulate NADPH oxidase genes and increase O2•-andH2O2 on tobacco leaves at 2 h after treatment. We further demonstrated that imidazole and DPI, inhibitors of NADPH oxidase, can promote recovery of stomatal aperture of tobacco leaves upon trehalose treatment. Exogenous trehalose increased tobacco leaf resistance to tobacco mosaic disease significantly in a concentration-dependent way. To elucidate the molecular mechanisms in response to exogenous trehalose, the transcriptomic responses of tobacco leaves with 10 (low concentration) or 50 (high concentration) mM of trehalose treatment at 2 or 24h were investigated through RNA-seq approach. In total, 1288 differentially expressed genes (DEGs) were found with different conditions of trehalose treatments relative to control. Among them, 1075 (83.5%) were triggered by low concentration of trehalose (10mM), indicating that low concentration of Tre is a better elicitor. Functional annotations with KEGG pathway analysis revealed that the DEGs are involved in metabolic pathway, biosynthesis of secondary metabolites, plant hormone signal transduction, plant-pathogen interaction, protein processing in ER, flavonoid synthesis and circadian rhythm and so on. The protein-protein interaction networks generated from the core DEGs regulated by all conditions strikingly revealed that eight proteins, including ClpB1, HSP70, DnaJB1-like protein, universal stress protein (USP) A-like protein, two FTSH6 proteins, GolS1-like protein and chloroplastics HSP, play a core role in responses to exogenous trehalose in tobacco leaves. Our data suggest that trehalose triggers a signal transduction pathway which involves calcium and ROS-mediated signalings. These core components could lead to partial resistance or tolerance to abiotic and biotic stresses. Moreover, 19 DEGs were chosen for analysis of quantitative real-time polymerase chain reaction (qRT-PCR). The qRT-PCR for the 19 candidate genes coincided with the DEGs identified via the RNA-seq analysis, sustaining the reliability of our RNA-seq data.