Center of Agricultural Sciences and Biodiversity, Federal University of Cariri, Brazil.
Colombian Corporation for Agricultural Research (AGROSAVIA), CI La Suiza, Rionegro, Colombia.
Plant Physiol Biochem. 2023 Oct;203:108066. doi: 10.1016/j.plaphy.2023.108066. Epub 2023 Sep 30.
We have previously shown that rice plants silenced for peroxisomal ascorbate peroxidase (OsAPX4-RNAi) display higher resilience to photosynthesis under oxidative stress and photorespiratory conditions. However, the redox mechanisms underlying that intriguing response remain unknown. Here, we tested the hypothesis that favorable effects triggered by peroxisomal APX deficiency on photosynthesis resilience under CAT inhibition are dependent on the intensity of photorespiration associated with the abundance of photosynthetic and redox proteins. Non-transformed (NT) and OsAPX4-RNAi silenced rice plants were grown under ambient (AC) or high CO (HC) conditions and subjected to 3-amino-1,2,4-triazole (3-AT)-mediated CAT activity inhibition. Photosynthetic measurements evidenced that OsAPX4-RNAi plants simultaneously exposed to CAT inhibition and HC lost the previously acquired advantage in photosynthesis resilience displayed under AC. Silenced plants exposed to environment photorespiration and CAT inhibition presented lower photorespiration as indicated by smaller Gly/Ser and Jo/Jc ratios and glycolate oxidase activity. Interestingly, when these silenced plants were exposed to HC and CAT-inhibition, they exhibited an inverse response compared to AC in terms of photorespiration indicators, associated with higher accumulation of proteins. Multivariate and correlation network analyses suggest that the proteomics changes induced by HC combined with CAT inhibition are substantially different between NT and OsAPX4-RNAi plants. Our results suggest that the intensity of photorespiration and peroxisomal APX-mediated redox signaling are tightly regulated under CAT inhibition induced oxidative stress, which can modulate the photosynthetic efficiency, possibly via a coordinated regulation of protein abundance and rearrangement, ultimately triggered by crosstalk involving HO levels related to CAT and APX activities in peroxisomes.
我们之前曾表明，过氧化物酶体抗坏血酸过氧化物酶（OsAPX4-RNAi）沉默的水稻植物在氧化应激和光呼吸条件下表现出更高的光合作用弹性。然而，该引人入胜的反应背后的氧化还原机制尚不清楚。在这里，我们测试了这样一个假设，即过氧化物酶体 APX 缺乏对 CAT 抑制下光合作用弹性的有利影响取决于与光合作用和氧化还原蛋白丰度相关的光呼吸强度。在环境（AC）或高 CO（HC）条件下生长的非转化（NT）和 OsAPX4-RNAi 沉默的水稻植物，并进行 3-氨基-1,2,4-三唑（3-AT）介导的 CAT 活性抑制。光合测量表明，同时暴露于 CAT 抑制和 HC 下的 OsAPX4-RNAi 植物失去了在 AC 下获得的光合作用弹性优势。暴露于环境光呼吸和 CAT 抑制的沉默植物表现出较低的光呼吸，如 Gly/Ser 和 Jo/Jc 比值和乙醛酸氧化酶活性较小所示。有趣的是，当这些沉默的植物暴露于 HC 和 CAT 抑制时，它们在光呼吸指标方面与 AC 呈现相反的反应，与更高的蛋白质积累相关。多变量和相关网络分析表明，在 NT 和 OsAPX4-RNAi 植物中，CAT 抑制诱导的氧化应激下，HC 结合 CAT 抑制诱导的蛋白质组学变化有很大不同。我们的结果表明，在 CAT 抑制诱导的氧化应激下，光呼吸强度和过氧化物酶体 APX 介导的氧化还原信号受到严格调控，这可以调节光合作用效率，可能通过涉及 CAT 和 APX 活性的 HO 水平的串扰来协调调节蛋白质丰度和重排。过氧化物酶体。
