A Brachypodium UDP-Glycosyltransferase Confers Root Tolerance to Deoxynivalenol and Resistance to Fusarium Infection
A Brachypodium UDP-Glycosyltransferase Confers Root Tolerance to Deoxynivalenol and Resistance to Fusarium Infection
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DOI：
10.1104/pp.16.00371
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发表时间：
2016-09-01
期刊：
影响因子：
7.4
通讯作者：
Dufresne, Marie
中科院分区：
文献类型：
--
作者：
Pasquet, Jean-Claude;Changenet, Valentin;Dufresne, Marie
镰刀菌头枯病（FHB）是由禾谷镰刀菌（Fusarium graminearum）引起的谷物病害，禾谷镰刀菌是一种能够在谷物上产生B型镰刀菌烯的真菌，包括对人类和动物有害的脱氧雪腐镰刀菌烯醇（DON）。对FHB的抗性是定量的，并且抗性的潜在机制知之甚少。抗性与通过次级代谢UDP-葡糖基转移酶（UGT）将DON缀合成葡糖基化形式脱氧雪腐镰刀菌烯醇-3-O-葡萄糖（D3G）的能力有关。然而，功能分析从来没有在一个单一的宿主物种进行。在这里，使用模型谷物物种二穗短柄草，我们表明，在植物中的Bradi5g03300 UGT转换DON到D3G。我们提出的证据表明，突变的Bradi5g03300增加根敏感性DON和穗的敏感性F。禾谷镰刀菌，而过量表达赋予增加的根耐受性的真菌毒素和穗抗真菌。表达和缀合的动力学表明，DON缀合的速度而不是D3G本身的增加是解释过表达品系的较高抗性的关键因素。离颖检测表明，Bradi5g03300基因的过表达而非突变改变了F. graminearum，强调参与DON感染的早期步骤。总之，这些结果表明，早期和有效的UGT介导的DON接合是必要的，足以建立抵抗F。并强调了一种新的策略，以促进FHB抗性的谷物。
Fusarium head blight (FHB) is a cereal disease caused by Fusarium graminearum, a fungus able to produce type B trichothecenes on cereals, including deoxynivalenol (DON), which is harmful for humans and animals. Resistance to FHB is quantitative, and the mechanisms underlying resistance are poorly understood. Resistance has been related to the ability to conjugate DON into a glucosylated form, deoxynivalenol-3-O-glucose (D3G), by secondary metabolism UDP-glucosyltransferases (UGTs). However, functional analyses have never been performed within a single host species. Here, using the model cereal species Brachypodium distachyon, we show that the Bradi5g03300 UGT converts DON into D3G in planta. We present evidence that a mutation in Bradi5g03300 increases root sensitivity to DON and the susceptibility of spikes to F. graminearum, while overexpression confers increased root tolerance to the mycotoxin and spike resistance to the fungus. The dynamics of expression and conjugation suggest that the speed of DON conjugation rather than the increase of D3G per se is a critical factor explaining the higher resistance of the overexpressing lines. A detached glumes assay showed that overexpression but not mutation of the Bradi5g03300 gene alters primary infection by F. graminearum, highlighting the involvement of DON in early steps of infection. Together, these results indicate that early and efficient UGT-mediated conjugation of DON is necessary and sufficient to establish resistance to primary infection by F. graminearum and highlight a novel strategy to promote FHB resistance in cereals.