Plant glutathione peroxidases (GPXs) are the main enzymes in the antioxidant defense system that sustain H₂O₂ homeostasis and normalize plant reaction to abiotic stress conditions. To understand the major roles of the GPX gene family in rapeseed (Brassica napus L.), for the first time, a genome-wide study identified 25 BnGPX genes in the rapeseed genome. The phylogenetic analysis discovered that GPX genes were grouped into four major groups (Group I–Group IV) from rapeseed and three closely interrelated plant species. The universal investigation uncovered that the BnGPXs gene experienced segmental duplications and positive selection pressure. Gene structure and motifs examination recommended that most of the BnGPX genes demonstrated a comparatively well-maintained exon-intron and motifs arrangement within the identical group. Likewise, we recognized five hormones-, four stress-, and numerous light-reactive cis-elements in the promoters of BnGPXs. Five putative bna-miRNAs from two families were also prophesied, targeting six BnGPXs genes. Gene ontology annotation results proved the main role of BnGPXs in antioxidant defense systems, ROS, and response to stress stimulus. Several BnGPXs genes revealed boosted expression profiles in many developmental tissues/organs, i.e., root, seed, leaf, stem, flower, and silique. The qRT-PCR based expression profiling exhibited that two genes (BnGPX21 and BnGPX23) were suggestively up-regulated against different hormones (ABA, IAA, and MeJA) and abiotic stress (salinity, cold, waterlogging, and drought) treatments. In short, our discoveries provide a basis for additional functional studies on the BnGPX genes in future rapeseed breeding programs.

中文翻译：

---

油菜籽 (Brassica napus L.) 中谷胱甘肽过氧化物酶 (GPX) 基因家族的全基因组表征揭示了它们在多种非生物应激反应和激素信号传导中的作用

植物谷胱甘肽过氧化物酶 (GPX) 是抗氧化防御系统中的主要酶，可维持 H ₂ O ₂稳态并使植物对非生物胁迫条件的反应正常化。为了了解GPX基因家族在油菜籽 ( Brassica napus L.) 中的主要作用，一项全基因组研究首次在油菜籽基因组中鉴定了 25 个BnGPX基因。系统发育分析发现，GPX基因分为来自油菜籽和三个密切相关的植物物种的四个主要组（组 I-组 IV）。普遍调查发现BnGPX基因经历了节段重复和正选择压力。基因结构和基序检查表明，大多数BnGPX基因在同一组内表现出相对维护良好的外显子-内含子和基序排列。同样，我们在BnGPX的启动子中识别出五种激素、四种应激和许多光反应顺式元件。还预言了来自两个家族的五个假定的 bna-miRNA，靶向六个BnGPX基因。基因本体注释结果证明了BnGPX在抗氧化防御系统、ROS 和对应激刺激的反应中的主要作用。几个BnGPX基因显示在许多发育组织/器官（即根、种子、叶、茎、花和长角果）中的表达谱增强。基于 qRT-PCR 的表达谱表明，两个基因（BnGPX21和BnGPX23）在不同激素（ABA、IAA 和 MeJA）和非生物胁迫（盐度、寒冷、涝渍和干旱）处理下被暗示性上调。简而言之，我们的发现为未来油菜育种计划中BnGPX基因的其他功能研究提供了基础。