Mao Jingqin, Burt Andrew J, Ramputh Al-I, Simmonds John, Cass Leslie, Hubbard Keith, Miller Shea, Altosaar Illimar, Arnason John T
Department of Biology, University of Ottawa, 30 Marie Curie Street, Ottawa, Ontario, Canada K1N 6N5.
J Agric Food Chem. 2007 Apr 4;55(7):2582-9. doi: 10.1021/jf063030f. Epub 2007 Mar 10.
An alteration in the secondary metabolism of maize (Zea mays L.) genetically modified with the wheat oxalate oxidase (OxO) gene was observed using HPLC and fluorescence microscopy. Phenolic concentrations in the OxO lines were significantly increased, but DIMBOA synthesis was reduced due to a diversion in the shikimate pathway leading to phenolic and hydroxamic acids. Ferulic acid exhibited the largest increase and accounted for 80.4% of the total soluble phenolics. Transcription of a 13-lipoxygenase gene, coding for a key enzyme involved in the regulation of secondary metabolism, was substantially higher in the OxO line than in the null line. To test whether the high levels of soluble phenolic acids, in particular ferulic acid, contributed to the insect resistance in the OxO maize, ferulic acid was administered in meridic diets to European corn borer (ECB). A significant negative correlation between ferulic acid concentration and ECB larval growth rate was found. Field testing during 2001 showed that OxO maize was more resistant to ECB, with leaf consumption and stalk-tunneling damage significantly reduced by 28-34 and 37-39%, respectively, on all of the OxO lines tested and confirming published 2000 findings.
利用高效液相色谱法（HPLC）和荧光显微镜观察发现，转小麦草酸氧化酶（OxO）基因的玉米（Zea mays L.）次生代谢发生了改变。OxO系中的酚类物质浓度显著增加，但由于莽草酸途径转向生成酚类和异羟肟酸，2,4-二羟基-7-甲氧基-1,4-苯并恶嗪-3-酮（DIMBOA）的合成减少。阿魏酸的增加幅度最大，占总可溶性酚类的80.4%。编码参与次生代谢调控的关键酶的13-脂氧合酶基因在OxO系中的转录水平显著高于空载体系。为了测试高水平的可溶性酚酸，尤其是阿魏酸，是否有助于OxO玉米的抗虫性，将阿魏酸添加到欧洲玉米螟（ECB）的全营养素饲料中。结果发现阿魏酸浓度与欧洲玉米螟幼虫生长速率之间存在显著的负相关。2001年的田间试验表明，OxO玉米对欧洲玉米螟更具抗性，在所有测试的OxO系中，叶片消耗量和茎杆隧道损伤分别显著降低了28 - 34%和37 - 39%，这证实了2000年发表的研究结果。
