利用代谢组技术研究南林895杨响应盐胁迫的生理代谢机制

为揭示林业树种在盐胁迫下的响应机制,以中等耐盐的美洲黑杨无性系后代南林895杨为材料,研究对照和盐胁迫(100 mmol·L^-1 NaCl)条件下杨树的生长情况,采用超高效液相色谱-四极杆-飞行时间质谱(UHPLC-QTOF-MS)技术分析叶片代谢物,利用实时荧光定量PCR(RT-qPCR)技术检测部分关键基因表达。结果表明,盐胁迫16 d导致杨树生长受抑制,但对其叶和根中的丙二醛含量无显著影响。正交偏最小二乘法判别分析(OPLS-DA)鉴定出两组的差异成分,筛选出5条代谢组分差异显著的代谢通路。盐胁迫下,南林895杨叶片中α-酮戊二酸、磷脂酰胆碱(PC)以及棉子糖家族低聚糖(RFOs)积累,而苹果酸和延胡索酸减少;核酸、细胞分裂素B、氨基酸和大部分有差异的酚类含量下降。同时,三羧酸循环、RFOs合成、果糖代谢,以及谷氨酸合成主途径等相关基因上调表达;而海藻糖激酶、酚类合成及谷氨酸合成支路等相关基因下调表达。本研究结果有利于深入了解林木树种耐盐机制,可为更好地发展杨树产业提供理论基础。

Metabolomics Analysis Reveals Mechanisms of Physiological Metabolism in the Adaption of Salt-Insensitive Nanlin 895 Poplar to Salt Stress

To understand the salt-tolerant mechanism of woody plant, the differences in growth of Populus Nanlin 895 (salt-insensitive clone hybrids of Populus deltoides Bart.CV. x Populus euramericana (Dode) Guineir CV) with 100 mmol·L^-1 NaCl treatment and without treatment were investigated, metabolite profiles were analyzed using a metabolomics analysis based on ultra performance liquid chromatography coupled with tandemquadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and gene expression were analyzed by real-time qPCR. The results showed after treatment for 16 d, the growth of Populus were stunted, but the malondialdehyde content in leaf and root were similar as the control. Supervised orthogonal partial least squares discriminant analysis(OPLS-DA)identified the differential metabolites between the control and the treatment, five pathways maybe regulated by salt were identified. Differential metabolites profiling showed that 2-oxoglutarate, phosphatidylcholine (PC) and raffinose family oligosaccharides (RFOs) were accumulated while malic acid and fumarate were declined in plants under salt stress. The levels of nucleic acids, cytokinin B, amino acids and most differently expressed phenolics were reduced. Gene expression profiling exhibited up-regulation of genes involved in tricarboxylic acid (TCA) cycle, RFOs biosynthesis, fructose metabolism and main pathway of glutamate biosynthesis, while down-regulation of genes encoding fucokinase, involved in phenolic biosynthesis and the bypass of glutamate biosynthesis. Our results extend the understanding of mechanisms in salt tolerance of Populus and provide a theoretical foundation for the development of poplar resources.