Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, has negatively impacted soybean production worldwide. This study evaluated the effect of foliar spray of acibenzolar-S-methyl (ASM) and jasmonic acid (JA) as well as silicon (Si) supplied, either by soil amendment using calcium silicate or through a nutrient solution, on ASR control as well as on the expression of some defence-related genes (phenylalanine ammonia-lyase (PAL), chitinase (CHI), chalcone isomerase (CHAL), lipoxygenase (LOX), pathogenesis-related protein 1 (PR-1) and metalloproteinase (MET)) in soybean plants infected or not by P. pachyrhizi. Foliar Si concentration ranged from 2.6 to 8.7 dag/kg for Si supply by soil application or through a nutrient solution in comparison with the control treatment (no Si supply). Higher foliar Si concentration contributed to reducing ASR severity greater than 30%, mainly if supplied through nutrient solution. The ASR severity was significantly reduced by 36% with the ASM spray in comparison with the control treatment without any expressive effect on the expression of the analysed genes. The JA spray did not result in reduction on ASR severity in comparison with the control treatment even though with higher transcript levels of PAL at 12 hai. The transcripts levels of MET and PAL were significantly higher for inoculated plants taking up Si from the soil in comparison to non-inoculated plants of this treatment at 72 hai. For Si supply through the nutrient solution (+Si plants), the transcripts levels of LOX and CHAL were significantly higher for inoculated plants in comparison to inoculated -Si ones at 12 hai. At 141 hai, the transcript level of PAL was significantly higher for inoculated + Si plants in comparison to inoculated -Si ones. In conclusion, Si supply contributed decisively to reduce ASR severity through the potentiation of some defence-related genes mainly PAL and CHAL involved, respectively, in the biosynthesis of phenolics and flavonoids.

中文翻译：

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厚壁壁孢霉感染大豆的差异基因表达对 acibenzolar-S-methyl、茉莉酸和硅的响应

亚洲豆锈病 (ASR) 由豆角锈病菌引起，对全球大豆生产产生了负面影响。本研究评估了通过使用硅酸钙土壤改良剂或通过营养液提供的硅苯 (ASM) 和茉莉酸 (JA) 以及硅 (Si) 叶面喷洒对 ASR 控制的影响。一些防御相关基因（苯丙氨酸解氨酶（PAL）、几丁质酶（CHI）、查尔酮异构酶（CHAL）、脂肪氧化酶（LOX）、发病相关蛋白1（PR-1）和金属蛋白酶（MET）的表达） ) 在大豆植株中是否被 P. pachyrhizi 感染。与对照处理（无硅供应）相比，通过土壤施用或通过营养液供应硅的叶面硅浓度范围为 2.6 至 8.7 dag/kg。较高的叶面硅浓度有助于将 ASR 严重程度降低 30% 以上，主要是通过营养液供应。与对照处理相比，ASM 喷雾剂的 ASR 严重程度显着降低了 36%，对分析基因的表达没有任何表达影响。与对照处理相比，JA 喷雾并未导致 ASR 严重性降低，即使在 12 海时 PAL 的转录水平较高。在 72 海里，与该处理的未接种植物相比，从土壤中吸收硅的接种植物的 MET 和 PAL 转录水平显着更高。对于通过营养液（+Si 植物）提供的 Si，与 12 海时接种的 -Si 植物相比，接种植物的 LOX 和 CHAL 的转录水平显着更高。在 141 海，与接种 -Si 植物相比，接种 + Si 植物的 PAL 转录水平显着更高。总之，通过增强一些防御相关基因，主要是 PAL 和 CHAL，分别参与酚类和黄酮类化合物的生物合成，Si 的供应对降低 ASR 的严重性做出了决定性的贡献。