Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics, Biotechnology, Ministry of Education, College of Biology and the Environments, Nanjing Forestry University, Nanjing 210037, China.
Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics, Biotechnology, Ministry of Education, College of Biology and the Environments, Nanjing Forestry University, Nanjing 210037, China.
Int J Biol Macromol. 2022 Jun 15;210:182-195. doi: 10.1016/j.ijbiomac.2022.05.012. Epub 2022 May 8.
Lignins and lignans are important for plant resistance to pathogens. Dirigent (DIR) proteins control the regio- and stereo-selectivity of coniferyl alcohol in lignan and lignin biosynthesis. DIR genes have been implicated in defense-related responses in several plant species, but their role in poplar immunity is unclear. We cloned PtDIR11 from Populus trichocarpa; we found that overexpression of PtDIR11 in poplar improved the lignan biosynthesis and enhanced the resistance of poplar to Septotis populiperda. PtDIR11 has a typical DIR domain; it belongs to the DIR-b/d family and is expressed in the cell membrane. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis showed that PtDIR11 expression was highest in stems, followed by leaves and roots. Furthermore, PtDIR11 expression was induced by S. populiperda, salicylic acid (SA), jasmonate (JA), and ethylene (ET) stresses. The recombinant PtDIR11 protein inhibited the growth of S. populiperda in vitro. Overexpressing (OE) PtDIR11 in "Nanlin 895" poplar enhanced growth. The OE lines exhibited minimal changes in lignin content, but their total lignan and flavonoid contents were significantly greater than in the wild-type (WT) lines. Overexpression of PtDIR11 affected multiple biological pathways of poplar, such as phenylpropanoid biosynthesis. The methanol extracts of OE-PtDIR11 lines showed greater anti-S. populiperda activity than did lignin extracts from the WT lines. Furthermore, OE-PtDIR11 lines upregulated genes that were related to phenylpropanoid biosynthesis and genes associated with the JA and ET signal transduction pathways; it downregulated genes that were related to SA signal transduction compared with the WT line under S. populiperda stress. Therefore, the OE transgenic plants analysis revealed that PtDIR11 is a good candidate gene for breeding of disease resistant poplar.
木质素和木脂素对植物抵抗病原体至关重要。导向蛋白（DIR）控制木质素和木脂素生物合成中松柏醇的区域和立体选择性。DIR 基因已被涉及到几种植物物种的防御相关反应，但它们在杨树中的作用尚不清楚。我们从毛白杨（Populus trichocarpa）中克隆了 PtDIR11；我们发现，杨树中 PtDIR11 的过表达提高了木脂素的生物合成，并增强了杨树对杨扇舟蛾（Septotis populiperda）的抗性。PtDIR11 具有典型的 DIR 结构域；它属于 DIR-b/d 家族，在细胞膜中表达。反转录定量聚合酶链反应（RT-qPCR）分析表明，PtDIR11 的表达在茎中最高，其次是叶和根。此外，PtDIR11 的表达受杨扇舟蛾、水杨酸（SA）、茉莉酸（JA）和乙烯（ET）胁迫诱导。重组 PtDIR11 蛋白在体外抑制杨扇舟蛾的生长。在“南林 895”杨树中过表达（OE）PtDIR11 增强了生长。OE 系的木质素含量没有明显变化，但它们的总木脂素和类黄酮含量明显高于野生型（WT）系。PtDIR11 的过表达影响杨树的多个生物学途径，如苯丙烷生物合成。OE-PtDIR11 系的甲醇提取物对杨扇舟蛾的活性大于 WT 系木质素提取物。此外，OE-PtDIR11 系在杨扇舟蛾胁迫下，与 WT 系相比，上调与苯丙烷生物合成相关的基因和与 JA 和 ET 信号转导途径相关的基因，下调与 SA 信号转导相关的基因。因此，OE 转基因植物分析表明，PtDIR11 是培育抗病杨树的候选基因。
