College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China.
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
Plant Cell Rep. 2019 Dec;38(12):1501-1514. doi: 10.1007/s00299-019-02461-7. Epub 2019 Aug 31.
CrCOMT, a COMT gene in Carex rigescens, was verified to enhance salt stress tolerance in transgenic Arabidopsis. High salinity severely restricts plant growth and development while melatonin can alleviate salt damage. Caffeic acid O-methyltransferase (COMT) plays an important role in regulating plant growth, development, and stress responses. COMT could also participate in melatonin biosynthesis. The objective of this study was to identify CrCOMT from Carex rigescens (Franch.) V. Krecz, a stress-tolerant grass species with a widespread distribution in north China, and to determine its physiological functions and regulatory mechanisms that impart tolerance to salt stress. The results showed that the transcription of CrCOMT exhibited different expression patterns under salt, drought, and ABA treatments. Transgenic Arabidopsis with the overexpression of CrCOMT exhibited improved growth and physiological performance under salt stress, such as higher lateral root numbers, proline level, and chlorophyll content, than in the wild type (WT). Overexpression of CrCOMT also increased dehydration tolerance in Arabidopsis. The transcription of salt response genes was more highly activated in transgenic plants than in the WT under salt stress conditions. In addition, the melatonin content in transgenic plants was higher than that in the WT after stress treatment. Taken together, our results indicated that CrCOMT may positively regulate stress responses and melatonin synthesis under salt stress.
CrCOMT，一种来自羊胡子草（Carex rigescens）的 COMT 基因，被证实可增强转基因拟南芥的耐盐性。高盐度严重限制植物的生长和发育，而褪黑素可以减轻盐害。咖啡酸-O-甲基转移酶（COMT）在调节植物的生长、发育和应激反应中起着重要作用。COMT 还可以参与褪黑素的生物合成。本研究的目的是从广泛分布于中国北方的耐盐性草本植物羊胡子草（Franch.）V. Krecz 中鉴定出 CrCOMT，并确定其赋予耐盐性的生理功能和调控机制。结果表明，CrCOMT 的转录在盐、干旱和 ABA 处理下表现出不同的表达模式。过表达 CrCOMT 的转基因拟南芥在盐胁迫下表现出更好的生长和生理性能，例如侧根数量、脯氨酸水平和叶绿素含量均高于野生型（WT）。过表达 CrCOMT 还提高了拟南芥的脱水耐性。在盐胁迫条件下，盐响应基因的转录在转基因植株中比在 WT 中更高地被激活。此外，在应激处理后，转基因植物中的褪黑素含量高于 WT。综上所述，我们的研究结果表明，CrCOMT 可能在盐胁迫下通过正向调节应激反应和褪黑素合成来发挥作用。
