UVR8 Mediates UV-B-Induced Arabidopsis Defense Responses against Botrytis cinerea by Controlling Sinapate Accumulation
UVR8 Mediates UV-B-Induced Arabidopsis Defense Responses against Botrytis cinerea by Controlling Sinapate Accumulation
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DOI：
10.1093/mp/sss025
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发表时间：
2012-05-01
期刊：
影响因子：
27.5
通讯作者：
Ballare, Carlos L.
中科院分区：
文献类型：
--
作者：
Demkura, Patricia V.;Ballare, Carlos L.
光正在成为植物对食草动物和病原体免疫反应的中心调节剂。太阳UV-B辐射作为植物防御的正向调节因子发挥着重要作用。然而，由于UV-B光子可以与植物组织中广泛的分子靶标相互作用，因此介导其对植物防御作用的机制仍然是难以捉摸的。在这里，我们表明，生态上有意义的剂量的UV-B辐射增加拟南芥耐坏死营养型真菌灰葡萄孢，这种效果是由光感受器UVR 8介导的。UV-B对植物抗性的影响在茉莉酸（JA）信号传导（jar 1 -1和P355：JAZ10.4）或罗汉源防御化合物（pen 2 -1，pad 3 -1，pen 2 pad 3）代谢受损的突变体中是保守的，这表明JA途径的调节和吲哚芥子油苷（IGS）或camalexin水平的变化都不参与这种反应。UV-B辐射，通过UVR 8的作用，增加了叶片组织中的黄酮类化合物和芥子酸的水平。UV-B对病原体抗性的影响在tt 4 -1中仍然可以检测到，tt 4 -1是一种缺乏查耳酮合酶的突变体，因此在类黄酮的合成中受损，但在fah 1 -7中不存在，fah 1 -7是一种缺乏阿魏酸5-羟化酶的突变体，这是芥子酸生物合成所必需的。总的来说，这些结果表明，UVR 8通过控制芥子酸生物合成途径的表达，在介导UV-B辐射对病原体抗性的影响中起着重要作用。
Light is emerging as a central regulator of plant immune responses against herbivores and pathogens. Solar UV-B radiation plays an important role as a positive modulator of plant defense. However, since UV-B photons can interact with a wide spectrum of molecular targets in plant tissues, the mechanisms that mediate their effects on plant defense have remained elusive. Here, we show that ecologically meaningful doses of UV-B radiation increase Arabidopsis resistance to the necrotrophic fungus Botrytis cinerea and that this effect is mediated by the photoreceptor UVR8. The UV-B effect on plant resistance was conserved in mutants impaired in jasmonate (JA) signaling (jar1-1 and P355:JAZ10.4) or metabolism of tryptophan-derived defense compounds (pen2-1, pad3-1, pen2 pad3), suggesting that neither regulation of the JA pathway nor changes in levels of indolic glucosinolates (iGS) or camalexin are involved in this response. UV-B radiation, acting through UVR8, increased the levels of flavonoids and sinapates in leaf tissue. The UV-B effect on pathogen resistance was still detectable in tt4-1, a mutant deficient in chalcone synthase and therefore impaired in the synthesis of flavonoids, but was absent in fah1-7, a mutant deficient in ferulic acid 5-hydroxylase, which is essential for sinapate biosynthesis. Collectively, these results indicate that UVR8 plays an important role in mediating the effects of UV-B radiation on pathogen resistance by controlling the expression of the sinapate biosynthetic pathway.