Salicylic acid (SA) plays an important role in the response of plants to abiotic stresses. Starvation stress affects plant cell metabolic activities, which further limits the normal growth and development of plants. It was reported that SA might play a regulatory role in the process of plant against starvation stress, but the mechanism involved in this process is still unclear. Thus, in this study, the transgenic plants overexpressing a SA binding protein 2 (SABP2) gene were exposed to starvation stress and the transgenic lines showed starvation-tolerant phenotype. Compared with wild-type (WT) plants, transgenic plants showed better growth status under poor-nutrition stress. Transgenic plants also showed more vigorous roots than WT plants. Physiological tests indicated that the transgenic plants showed higher relative water content (RWC), chlorophyll content, photosynthetic capacity, endogenous SA content, and lower ROS level compared to WT plants. Transcriptome analysis of tobacco plants identified 3, 748 differentially expressed genes (DEGs) between transgenic and WT plants under starvation stress. These DEGs are mainly involved in glycolysis/gluconeogenesis pathway group, MAPK signaling pathway group and plant hormone signal transduction pathway group. As determined by qPCR, up-regulated expression of fifteen genes such as abscisic acid receptor PYR1-like gene (NtPYR1-like), bidirectional sugar transporter N3-like gene (NtSWEETN3-like) and superoxide dismutase [Fe] chloroplastic-like gene (NtFeSOD-like), etc., was observed in transgenic plants under poor-nutrition stress which was in accordance with RNA-sequencing results. The modified pathways involved in plant hormone signaling are thought to be at least one of the main causes of the increased starvation tolerance of transgenic tobacco plants with altered SA homeostasis.

中文翻译：

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内源SA积累的增强改善了过度表达SA结合蛋白基因的转基因烟草植物的营养不良胁迫耐受性


水杨酸（SA）在植物对非生物胁迫的反应中发挥着重要作用。饥饿胁迫影响植物细胞代谢活动，进一步限制植物的正常生长发育。据报道，SA可能在植物抵抗饥饿胁迫的过程中发挥调节作用，但其具体机​​制尚不清楚。因此，在本研究中，过表达SA结合蛋白2（SABP2）基因的转基因植物暴露于饥饿胁迫，并且转基因品系表现出饥饿耐受表型。与野生型（WT）植物相比，转基因植物在营养不良胁迫下表现出更好的生长状态。转基因植物还表现出比野生型植物更旺盛的根系。生理测试表明，与WT植物相比，转基因植物表现出较高的相对水分含量(RWC)、叶绿素含量、光合能力、内源SA含量和较低的ROS水平。对烟草植物的转录组分析发现，饥饿胁迫下转基因植物和野生型植物之间存在 3, 748 个差异表达基因 (DEG)。这些DEG主要涉及糖酵解/糖异生途径组、MAPK信号途径组和植物激素信号转导途径组。 qPCR检测发现，脱落酸受体PYR1样基因（NtPYR1样）、双向糖转运蛋白N3样基因（NtSWEETN3样）和超氧化物歧化酶[Fe]叶绿体样基因等15个基因的表达上调。在营养不良胁迫下的转基因植物中观察到NtFeSOD-like）等，这与RNA测序结果一致。 植物激素信号传导途径的改变被认为至少是 SA 稳态改变的转基因烟草植物耐饥饿性增强的主要原因之一。