Ascorbate peroxidase (APX) is an important antioxidant enzyme. APXs in maize are encoded by multiple genes and exist as isoenzymes. The evolutionary history and functional divergence of the maize APX gene family were analyzed through comparative genomic and experimental data on the Internet in this paper. APX genes in higher plants were divided into classes A, B, and C. Each type of APX gene in angiosperms only had one ancestral gene that was duplicated along with the genome duplication or local (or tandem) duplication of the angiosperm. A total of eight genes were retained in maize and named APXa1, APXa2, APXa3, APXb1, APXb2, APXc1.1, APXc1.2, and APXc2. The APX genes of class A were located in the chloroplasts or mitochondria, and the class B and C genes were localized in the peroxisomes and cytoplasm, respectively. The expression patterns of eight APXs were different in vegetative and reproductive organs at different growth and development stages. APXa1 and APXb1 of maize may participate in the antioxidant metabolism of vegetative organs under normal conditions. APXa2, APXb2, APXc1.1, and APXc1.2 may be involved in the stress response, and APXb2 and APXc2 may participate in the senescence response. These results provide a basis for cultivating high-yield and resistant maize varieties.

中文翻译：

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玉米抗坏血酸过氧化物酶基因的分子进化及其功能差异

抗坏血酸过氧化物酶（APX）是一种重要的抗氧化酶。玉米中的 APX 由多个基因编码并以同工酶的形式存在。本文通过比较基因组和互联网上的实验数据分析了玉米APX基因家族的进化历史和功能差异。高等植物中的 APX 基因分为 A、B 和 C 类。被子植物中的每一类 APX 基因只有一个祖先基因，该基因随被子植物的基因组复制或局部（或串联）复制而复制。共有 8 个基因被保留在玉米中，并命名为 APXa1、APXa2、APXa3、APXb1、APXb2、APXc1.1、APXc1.2 和 APXc2。A类APX基因位于叶绿体或线粒体中，B类和C类基因分别位于过氧化物酶体和细胞质中。8种APXs在不同生长发育阶段的营养和生殖器官中的表达模式不同。玉米的APXa1和APXb1在正常情况下可能参与营养器官的抗氧化代谢。APXa2、APXb2、APXc1.1和APXc1.2可能参与应激反应，APXb2和APXc2可能参与衰老反应。这些结果为培育高产抗病玉米品种提供了依据。