A Novel Soybean Dirigent Gene GmDIR22 Contributes to Promotion of Lignan Biosynthesis and Enhances Resistance to Phytophthora sojae.
A Novel Soybean Dirigent Gene GmDIR22 Contributes to Promotion of Lignan Biosynthesis and Enhances Resistance to Phytophthora sojae.
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新型大豆 Dirigent 基因 GmDIR22 有助于促进木脂素生物合成并增强对大豆疫霉的抗性
DOI：
10.3389/fpls.2017.01185
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发表时间：
2017
影响因子：
5.6
通讯作者：
Zhang S
中科院分区：
文献类型：
--
作者：
Li N;Zhao M;Liu T;Dong L;Cheng Q;Wu J;Wang L;Chen X;Zhang C;Lu W;Xu P;Zhang S
大豆疫霉根腐病是由大豆疫霉卵菌引起的世界性大豆毁灭性病害。植物趋异蛋白（dirigent protein，DIPs）参与木脂素或木质素样分子的生物合成，在植物防御反应、次生代谢和抗病性等方面发挥重要作用。在本工作中，一个新的表达序列标签被鉴定为在高抗大豆品种绥农10号中被大豆疫霉菌感染后表达上调。使用cDNA末端的快速扩增分离全长cDNA，并命名为GmDIR 22（GenBank登录号HQ_993047）。GmDIR 22全长789 bp，包含一个567 bp的开放阅读框，编码188个氨基酸。序列分析表明，GmDIR 22在第43-187位氨基酸残基处含有一个保守的差异结构域。实时荧光定量PCR结果表明，大豆GmDIR 22 mRNA在茎中表达量最高，其次是根和叶。GmDIR 22受大豆疫霉和赤霉酸（GA 3）诱导表达，对水杨酸、茉莉酸甲酯和脱落酸也有响应。GmDIR 22在拟南芥原生质体中瞬时表达时靶向细胞膜。从大肠杆菌中纯化的GmDIR 22重组蛋白能有效地将E-松柏醇偶联为木脂素（+）-松柏醇。因此，GmDIR 22在转基因大豆中的过表达增加了总木脂素积累。此外，转GmDIR 22基因植株的木脂素提取物有效抑制大豆疫霉菌丝生长。此外，GmDIR 22在感病大豆品种‘东农50’中的转基因过量表达增强了其对大豆疫霉的抗性。总的来说，这些数据表明GmDIR 22的主要作用可能涉及木脂素生物合成的调节，并且其有助于对大豆疫霉的抗性。
Phytophthora root and stem rot caused by the oomycete pathogen Phytophthora sojae is a destructive disease of soybean worldwide. Plant dirigent proteins (DIR) are proposed to have roles in biosynthesis of either lignan or lignin-like molecules, and are important for defense responses, secondary metabolism, and pathogen resistance. In the present work, a novel DIR gene expressed sequence tag is identified as up-regulated in the highly resistant soybean cultivar ‘Suinong 10’ inoculated with P. sojae. The full length cDNA is isolated using rapid amplification of cDNA ends, and designated GmDIR22 (GenBank accession no. HQ_993047). The full length GmDIR22 is 789 bp and contains a 567 bp open reading frame encoding a polypeptide of 188 amino acids. The sequence analysis indicated that GmDIR22 contains a conserved dirigent domain at amino acid residues 43–187. The quantitative real-time reverse transcription PCR demonstrated that soybean GmDIR22 mRNA is expressed most highly in stems, followed by roots and leaves. The treatments with stresses demonstrated that GmDIR22 is significantly induced by P. sojae and gibberellic acid (GA3), and also responds to salicylic acid, methyl jasmonic acid, and abscisic acid. The GmDIR22 is targeted to the cytomembrane when transiently expressed in Arabidopsis protoplasts. Moreover, The GmDIR22 recombinant protein purified from Escherichia coli could effectively direct E-coniferyl alcohol coupling into lignan (+)-pinoresinol. Accordingly, the overexpression of GmDIR22 in transgenic soybean increased total lignan accumulation. Moreover, the lignan extracts from GmDIR22 transgenic plants effectively inhibits P. sojae hyphal growth. Furthermore, the transgenic overexpression of GmDIR22 in the susceptible soybean cultivar ‘Dongnong 50’ enhances its resistance to P. sojae. Collectively, these data suggested that the primary role of GmDIR22 is probably involved in the regulation of lignan biosynthesis, and which contributes to resistance to P. sojae.