Abstract

Low temperature (LT) is an important elicitor that triggers anthocyanin biosynthesis. To investigate whether the reactive oxygen species (ROS) produced via RBOH are involved in this process, we analysed the function and mechanism of ROS produced via RBOH during LT-induced anthocyanin biosynthesis in Begonia semperflorens Link & Otto. The results showed that BsRBOHD transcription was upregulated in LT-grown seedlings at the 3rd hour, which was followed by the upregulation of anthocyanin-biosynthesis genes at the 5–9th hour, leading to anthocyanin accumulation on the 2nd day. The LT-induced increases in ROS production, BsRBOHD and anthocyanin-biosynthesis gene transcription, and anthocyanin content were abolished by the pre-treatment of seedlings with DPI [an inhibitor of nicotinamide adenine nucleoside phosphorylase (NADPH) oxidase or DMTU (a H₂O₂ scavenger)], but were promoted by pre-treatment with NADPH (a substrate of NADPH oxidase). Changes in the chlorophyll fluorescence parameters showed that pre-treatment of DPI or DMTU alleviated the LT-induced decrease in the seedling chlorophyll content and a/b ratio, which subsequently alleviated the LT-induced decreases in the ABS/CSm, TRo/CSm, RC/CSm, ETo/CSm and REo/CSm values. In contrast, NAPDH pre-treatment intensified these changes. Therefore, we suggest that ROS produced via BsRBOHD may be involved in the LT-induced anthocyanin biosynthesis by strengthening the overaccumulation of ROS produced by the overexcitation of PSII reaction centres and overflux from \({\text{Q}}_{{\text{A}}}^{ - }\) to NADP⁺ in B. semperflorens.

中文翻译：

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通过BsRBOHD产生的ROS在低温诱导的秋海棠花青素生物合成中起重要作用

摘要

低温（LT）是触发花色苷生物合成的重要诱因。为了调查是否通过RBOH产生的活性氧（ROS）参与了此过程，我们分析了LT诱导的秋海棠海棠花青素的生物合成过程中，通过RBOH产生的ROS的功能和机理。结果表明，在LT生长的幼苗中，BsRBOHD转录在第3小时上调，然后在第5-9小时，花色苷生物合成基因上调，导致第2天花色苷积累。LT引起的ROS产量增加（BsRBOHD）通过用DPI [烟酰胺腺嘌呤核苷磷酸化酶（NADPH）氧化酶抑制剂或DMTU（H ₂ O ₂清除剂）的抑制剂]预处理幼苗，消除了花青素的生物合成基因转录和花青素含量，但通过预先处理提高了花青素的含量。用NADPH（NADPH氧化酶的底物）处理。叶绿素荧光参数的变化表明，DPI或DMTU的预处理减轻了LT诱导的幼苗叶绿素含量和a / b比的降低，从而减轻了LT诱导的ABS / CSm，TRo / CSm， RC / CSm，ETo / CSm和REo / CSm值。相反，NAPDH预处理加剧了这些变化。因此，我们建议通过BsRBOHD产生ROS可能通过加强PSII反应中心过度激发产生的ROS过度积累和\（{\ text {Q}} _ {{\ text {A}}} ^ {-}引起的ROS积累而参与LT诱导的花色苷生物合成。\）到NADP ⁺在B.秋海棠。