A Single-Electron Reducing Quinone Oxidoreductase Is Necessary to Induce Haustorium Development in the Root Parasitic Plant Triphysaria
A Single-Electron Reducing Quinone Oxidoreductase Is Necessary to Induce Haustorium Development in the Root Parasitic Plant Triphysaria
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DOI：
10.1105/tpc.110.074831
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发表时间：
2010-04-01
期刊：
影响因子：
11.6
通讯作者：
Yoder, John I.
中科院分区：
文献类型：
--
作者：
Bandaranayake, Pradeepa C. G.;Filappova, Tatiana;Yoder, John I.
萝卜科寄生植物在与寄主根接触或化学吸器诱导因子的反应中产生吸器。这篇手稿中的实验验证了这一假说，即喹啉诱导因子激活吸器发育的信号机制是由对苯二酚和对苯二酚态之间的氧化还原循环启动的。先前从寄生植物杂色三叶草的根中分离到两个编码不同的苯醌氧化还原酶的cDNA。QR1编码一个单电子还原的NADPH苯醌氧化还原酶，类似于Zeta-晶体蛋白。QR2酶催化两个典型的外源解毒电子还原。QR1和QR2转录本在对化学诱导因子的初级反应中上调，但只有QR1转录上调是对寄主根的反应。利用RNA干扰技术来减少三叶草根中的QR1和QR2转录本，以评估它们形成吸器的能力。沉默QR1的根吸器发育显著减少，而沉默QR2的根吸器发育不明显。不常见的QR1转基因根确实形成吸器，其QR1水平与非转基因根相似。这些实验表明，QR1是吸器信号转导途径中最早的基因之一，编码一种苯醌氧化还原酶，是吸器诱导因子氧化还原生物激活所必需的。
Parasitic plants in the Orobanchaceae develop haustoria in response to contact with host roots or chemical haustoria-inducing factors. Experiments in this manuscript test the hypothesis that quinolic-inducing factors activate haustorium development via a signal mechanism initiated by redox cycling between quinone and hydroquinone states. Two cDNAs were previously isolated from roots of the parasitic plant Triphysaria versicolor that encode distinct quinone oxidoreductases. QR1 encodes a single-electron reducing NADPH quinone oxidoreductase similar to zeta-crystallin. The QR2 enzyme catalyzes two electron reductions typical of xenobiotic detoxification. QR1 and QR2 transcripts are upregulated in a primary response to chemical-inducing factors, but only QR1 was upregulated in response to host roots. RNA interference technology was used to reduce QR1 and QR2 transcripts in Triphysaria roots that were evaluated for their ability to form haustoria. There was a significant decrease in haustorium development in roots silenced for QR1 but not in roots silenced for QR2. The infrequent QR1 transgenic roots that did develop haustoria had levels of QR1 similar to those of nontransgenic roots. These experiments implicate QR1 as one of the earliest genes on the haustorium signal transduction pathway, encoding a quinone oxidoreductase necessary for the redox bioactivation of haustorial inducing factors.