• Soil salinity and drought limit sweet potato yield. Scavenging of reactive oxygen species (ROS) by peroxidases (PRXs) is essential during plant stress responses, but how PRX expression is regulated under abiotic stress is not well understood.
• Here, we report that the B-box (BBX) family transcription factor IbBBX24 activates the expression of the class III peroxidase gene IbPRX17 by binding to its promoter. Overexpression of IbBBX24 and IbPRX17 significantly improved the tolerance of sweet potato to salt and drought stresses, whereas reducing IbBBX24 expression increased their susceptibility. Under abiotic stress, IbBBX24- and IbPRX17-overexpression lines showed higher peroxidase activity and lower H₂O₂ accumulation compared with the wild-type. RNA sequencing analysis revealed that IbBBX24 modulates the expression of genes encoding ROS scavenging enzymes, including PRXs.
• Moreover, interaction between IbBBX24 and the APETALA2 (AP2) protein IbTOE3 enhances the ability of IbBBX24 to activate IbPRX17 transcription. Overexpression of IbTOE3 improved the tolerance of tobacco plants to salt and drought stresses by scavenging ROS.
• Together, our findings elucidate the mechanism underlying the IbBBX24–IbTOE3–IbPRX17 module in response to abiotic stress in sweet potato and identify candidate genes for developing elite crop varieties with enhanced abiotic stress tolerance.

中文翻译：

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IbBBX24–IbTOE3–IbPRX17 模块通过清除甘薯中的活性氧来增强非生物胁迫耐受性

• 土壤盐分和干旱限制了甘薯的产量。过氧化物酶 (PRX) 清除活性氧 (ROS) 在植物胁迫响应期间是必不可少的，但在非生物胁迫下如何调节PRX表达尚不清楚。
• 在这里，我们报告 B 盒 (BBX) 家族转录因子 IbBBX24通过与其启动子结合来激活 III 类过氧化物酶基因IbPRX17的表达。IbBBX24和IbPRX17的过表达显着提高了甘薯对盐和干旱胁迫的耐受性，而降低IbBBX24表达增加了它们的易感性。在非生物胁迫下，与野生型相比， IbBBX24-和IbPRX17-过表达系表现出更高的过氧化物酶活性和更低的H ₂ O _2积累。RNA 测序分析显示 IbBBX24 调节编码 ROS 清除酶的基因的表达，包括 PRX。
• 此外，IbBBX24 与 APETALA2 (AP2) 蛋白 IbTOE3 之间的相互作用增强了 IbBBX24 激活IbPRX17转录的能力。IbTOE3的过表达通过清除 ROS 提高了烟草植物对盐和干旱胁迫的耐受性。
• 总之，我们的研究结果阐明了 IbBBX24–IbTOE3–IbPRX17 模块响应甘薯非生物胁迫的机制，并确定了开发具有增强的非生物胁迫耐受性的优良作物品种的候选基因。