Shen Guoan, Pang Yongzhen, Wu Weisheng, Miao Zhiqi, Qian Hongmei, Zhao Lingxia, Sun Xiaofen, Tang Kexuan
Plant Biotechnology Research Center, School of Agriculture and Biology, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, SJTU-SIBS-PSU Joint Center for Life Sciences, Shanghai Jiao Tong University, PR China.
J Plant Physiol. 2005 Oct;162(10):1160-8. doi: 10.1016/j.jplph.2005.01.019.
A novel defensin gene was isolated from Ginkgo biloba. The full-length cDNA of G. biloba defensin (designated as Gbd) was 534bp. The cDNA contained a 240-bp open reading frame encoding an 80-amino acid protein of 5.68 kDa with a potential 30 aa signal peptide. The putative GbD mature protein showed striking similarity to other plant defensins, representing low molecular size antimicrobial polypeptides. Eight cysteine sites conserved in plant defensins were also found in GbD at similar positions. Three-dimensional structure modeling showed that GbD strongly resembled defensin from tobacco (NaD1) and consisted of an alpha-helix and a triple-strand antiparallel beta-sheet that were stabilized by four intramolecular disulfide bonds, implying GbD may have functions similar to NaD1. The genomic DNA gel blot indicated that Gbd belonged to a multigene family. Expression analysis revealed that Gbd was up-regulated by wounding and methyl jasmonate treatments, suggesting that Gbd is potentially involved in plant resistance or tolerance to pathogens during wounding.
从银杏中分离出一个新的防御素基因。银杏防御素（命名为Gbd）的全长cDNA为534bp。该cDNA包含一个240bp的开放阅读框，编码一个80个氨基酸的蛋白质，分子量为5.68kDa，带有一个潜在的30个氨基酸的信号肽。推测的GbD成熟蛋白与其他植物防御素具有显著相似性，代表低分子量抗菌多肽。在GbD中也在相似位置发现了植物防御素中保守的八个半胱氨酸位点。三维结构建模表明，GbD与烟草防御素（NaD1）非常相似，由一个α-螺旋和一个三链反平行β-折叠组成，通过四个分子内二硫键稳定，这意味着GbD可能具有与NaD1相似的功能。基因组DNA凝胶印迹表明Gbd属于一个多基因家族。表达分析显示，Gbd在伤口处理和茉莉酸甲酯处理后上调，表明Gbd在伤口处理期间可能参与植物对病原体的抗性或耐受性。
