Poppenberger Brigitte, Berthiller Franz, Lucyshyn Doris, Sieberer Tobias, Schuhmacher Rainer, Krska Rudolf, Kuchler Karl, Glössl Josef, Luschnig Christian, Adam Gerhard
Center of Applied Genetics, BOKU - University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
J Biol Chem. 2003 Nov 28;278(48):47905-14. doi: 10.1074/jbc.M307552200. Epub 2003 Sep 11.
Plant pathogenic fungi of the genus Fusarium cause agriculturally important diseases of small grain cereals and maize. Trichothecenes are a class of mycotoxins produced by different Fusarium species that inhibit eukaryotic protein biosynthesis and presumably interfere with the expression of genes induced during the defense response of the plants. One of its members, deoxynivalenol, most likely acts as a virulence factor during fungal pathogenesis and frequently accumulates in grain to levels posing a threat to human and animal health. We report the isolation and characterization of a gene from Arabidopsis thaliana encoding a UDP-glycosyltransferase that is able to detoxify deoxynivalenol. The enzyme, previously assigned the identifier UGT73C5, catalyzes the transfer of glucose from UDP-glucose to the hydroxyl group at carbon 3 of deoxynivalenol. Using a wheat germ extract-coupled transcription/translation system we have shown that this enzymatic reaction inactivates the mycotoxin. This deoxynivalenol-glucosyltransferase (DOGT1) was also found to detoxify the acetylated derivative 15-acetyl-deoxynivalenol, whereas no protective activity was observed against the structurally similar nivalenol. Expression of the glucosyltransferase is developmentally regulated and induced by deoxynivalenol as well as salicylic acid, ethylene, and jasmonic acid. Constitutive overexpression in Arabidopsis leads to enhanced tolerance against deoxynivalenol.
镰刀菌属的植物病原真菌会引发对小粒谷物和玉米具有重要农业影响的病害。单端孢霉烯族毒素是由不同镰刀菌物种产生的一类霉菌毒素，它会抑制真核生物的蛋白质生物合成，并可能干扰植物防御反应过程中诱导基因的表达。其成员之一脱氧雪腐镰刀菌烯醇很可能在真菌致病过程中作为一种毒力因子，并且经常在谷物中积累到对人类和动物健康构成威胁的水平。我们报告了从拟南芥中分离并鉴定出一个编码UDP - 糖基转移酶的基因，该酶能够对脱氧雪腐镰刀菌烯醇进行解毒。这种酶先前被命名为UGT73C5，它催化葡萄糖从UDP - 葡萄糖转移到脱氧雪腐镰刀菌烯醇3位碳的羟基上。利用小麦胚芽提取物偶联的转录/翻译系统，我们证明了这种酶促反应会使霉菌毒素失活。这种脱氧雪腐镰刀菌烯醇糖基转移酶（DOGT1）也被发现能够对乙酰化衍生物15 - 乙酰 - 脱氧雪腐镰刀菌烯醇进行解毒，然而对结构相似的雪腐镰刀菌烯醇未观察到保护活性。糖基转移酶的表达受发育调控，并且会被脱氧雪腐镰刀菌烯醇以及水杨酸、乙烯和茉莉酸诱导。在拟南芥中组成型过表达会导致对脱氧雪腐镰刀菌烯醇的耐受性增强。
