Key Laboratory of Sugarcane Biology and Genetic Breeding, Fujian Agriculture and Forestry University, Ministry of Agriculture, Fuzhou, 350002, China.
Plant Cell Rep. 2012 Oct;31(10):1801-12. doi: 10.1007/s00299-012-1293-1. Epub 2012 Jun 14.
Dirigent and dirigent-like family proteins contain a number of proteins involved in lignification or in the response to pathogen infection and abiotic stress in plants. In the present study, a full-length cDNA sequence of a dirigent-like gene designated ScDir (GenBank Accession Number JQ622282) was obtained from sugarcane based on the stem full-length cDNA library. The ScDir gene was 819-bp long, including a 564-bp ORF encoding 187 amino acid residues. The protein N-terminus contained signal peptides at amino acid residues of 1-25 and transmembrane regions at 7-26 aa. A his-tagged ScDir protein with an estimated molecular mass of 27.4 kDa was expressed in Escherichia coli system. The expressed ScDir protein had increased the host cell's tolerance to PEG and NaCl. When an endogenous GAPDH gene was used as internal control, results from real-time qPCR demonstrated that the ScDir mRNA amount in sugarcane stems was significantly higher than that in the roots, leaves and buds by 18.64 ± 0.48, 25,635.16 ± 2,966.03 and 721.50 ± 8.17-fold, respectively. The ScDir transcript levels in sugarcane seedling increased under H(2)O(2), PEG or NaCl stress. The expression level of ScDir was significantly upregulated under PEG stress, and the highest level was observed at 12 h after stress. Thus, both the ScDir-hosted cell performance and the enhanced expressions in sugarcane imply that the ScDir gene is involved in the response to abiotic stresses of drought, salts and oxidation. The transcription of the ScDir gene is highly stem-specific, as revealed by real-time qPCR. Key message A novel sugarcane Sc-Dir gene, DIRd subfamily, which is highly stalk-specific expression and involved in the response to artificial stresses of drought, salts, and oxidatives.
导向蛋白和类导向蛋白家族包含许多参与木质素形成或植物对病原体感染和非生物胁迫反应的蛋白质。本研究以甘蔗茎全长 cDNA 文库为基础，从甘蔗中获得了一个命名为 ScDir（GenBank 登录号 JQ622282）的类导向蛋白全长 cDNA 序列。ScDir 基因长 819bp，包含一个编码 187 个氨基酸残基的 564bp ORF。蛋白 N 端在 1-25 位氨基酸残基处含有信号肽，在 7-26 位氨基酸残基处含有跨膜区。一个带有 His 标签的 ScDir 蛋白在大肠杆菌系统中表达，预计分子量为 27.4kDa。表达的 ScDir 蛋白增加了宿主细胞对 PEG 和 NaCl 的耐受性。当以内源 GAPDH 基因为内参时，实时 qPCR 结果表明，ScDir mRNA 在甘蔗茎中的含量分别比根、叶和芽高 18.64±0.48、25635.16±2966.03 和 721.50±8.17 倍。在 H 2 O 2 、PEG 或 NaCl 胁迫下，甘蔗幼苗中 ScDir 转录本水平升高。在 PEG 胁迫下 ScDir 的表达水平显著上调，胁迫后 12h 达到最高水平。因此，ScDir 基因参与了干旱、盐和氧化胁迫的非生物胁迫反应，既能提高宿主细胞的性能，又能增强其表达。实时 qPCR 结果显示，ScDir 基因的转录具有高度的茎特异性。
