School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
Plant Sci. 2020 Mar;292:110384. doi: 10.1016/j.plantsci.2019.110384. Epub 2019 Dec 19.
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.
水杨酸（SA）在植物应对非生物胁迫的反应中起着重要作用。饥饿胁迫会影响植物细胞的代谢活动，从而进一步限制植物的正常生长和发育。有报道称，SA 可能在植物应对饥饿胁迫的过程中发挥调节作用，但这一过程涉及的机制尚不清楚。因此，在本研究中，过表达水杨酸结合蛋白 2（SABP2）基因的转基因植物受到饥饿胁迫，表现出饥饿耐受表型。与野生型（WT）植物相比，在营养缺乏胁迫下，转基因植物表现出更好的生长状态。转基因植物的根系也比 WT 植物更健壮。生理测试表明，与 WT 植物相比，转基因植物表现出更高的相对含水量（RWC）、叶绿素含量、光合能力、内源性 SA 含量和更低的 ROS 水平。对烟草植物的转录组分析鉴定出在饥饿胁迫下，转基因和 WT 植物之间有 3748 个差异表达基因（DEGs）。这些 DEGs 主要参与糖酵解/糖异生途径群、MAPK 信号通路群和植物激素信号转导途径群。通过 qPCR 确定，在营养缺乏胁迫下，十五个基因如脱落酸受体 PYR1 样基因（NtPYR1-like）、双向糖转运蛋白 N3 样基因（NtSWEETN3-like）和超氧化物歧化酶[Fe]类叶绿体基因（NtFeSOD-like）等的表达上调，这与 RNA-seq 结果一致。参与植物激素信号转导的途径的改变被认为是改变 SA 稳态的转基因烟草植物饥饿耐受性增加的至少一个主要原因之一。
