Fraxinus mandshurica 4-coumarate-CoA ligase 2 enhances drought and osmotic stress tolerance of tobacco by increasing coniferyl alcohol content

• Published in: Plant physiology and biochemistry Vol. 155; pp. 697 - 708
• Main Authors: Chen, Xiaohui, Su, Wenlong, Zhang, Han, Zhan, Yaguang, Zeng, Fansuo
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.10.2020
• Subjects: 4-Coumarate-CoA ligase; Coenzyme A Ligases - physiology; Coniferyl alcohol; Drought stress; Droughts; Fraxinus - enzymology; Fraxinus mandshurica; Gene Expression Regulation, Plant; Ligases; Lignin; Malondialdehyde; Nicotiana - genetics; Nicotiana - physiology; Osmotic Pressure; Osmotic stress; Phenols - metabolism; Plant Proteins - physiology; Plants, Genetically Modified - physiology; Reactive Oxygen Species; Stress, Physiological; Drought stress; Lignin; Coniferyl alcohol; 4-Coumarate-CoA ligase; Fraxinus mandshurica; Osmotic stress
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2020.08.031

4-Coumarate-CoA ligase (4CL) is an important branch point in the phenylpropane pathway and plays important roles in plant growth and development. In this study, the 4CL2 gene from Fraxinus mandshurica (designated Fm4CL2) was identified and isolated. Sequence analysis revealed that Fm4CL2 is a type I 4CL gene involved in lignin biosynthesis. Analysis of cell wall components revealed that Fm4CL2-overexpressing (OE-Fm4CL2) tobacco showed increased lignin content (by 58.9%) and decreased hemicellulose content (by 41.2%). Detection of small-molecule metabolites in the lignin pathway revealed that coumaric acid content decreased by 48% and coniferyl alcohol content increased by 250% compared with the control values. Compared with wild type, OE-Fm4CL2 tobacco showed increased xylem cell layer number (by 120%) and cell wall thickness (by 54.5%). Under osmotic stress, transgenic tobacco showed higher growth than wild-type tobacco. The germination rate of transgenic tobacco was higher than that of wild type. Reactive oxygen species accumulation and malondialdehyde content were significantly lower in transgenic tobacco than in wild type. Under drought, the expression of stress-related genes was higher in 35S–Fm4CL2-infected Fraxinus mandshurica plants than in control plants. These results indicate that Fm4CL2 overexpression can enhance drought and osmotic stress tolerance of plants. •Overexpression of Fm4CL2 in tobacco can change tobacco cell wall components.•Increased xylem cell layer and cell wall thickness in OE-Fm4CL2 tobacco.•OE-Fm4CL2 tobacco shows higher resistance to drought and salt.