College of Horticulture and Gardening, Yangtze University, Jingzhou, 434025, Hubei, China.
Faculty of Science, Department of Chemistry, University of Hradec Kralove, Hradec Kralove, 50003, Czech Republic.
Plant Cell Rep. 2024 Apr 20;43(5):123. doi: 10.1007/s00299-024-03218-7.
CitCAT1 and CitCAT2 were cloned and highly expressed in mature leaves. High temperatures up-regulated CitCAT1 expression, while low temperatures and Diversispora versiformis up-regulated CitCAT2 expression, maintaining a low oxidative damage. Catalase (CAT), a tetrameric heme-containing enzyme, removes hydrogen peroxide (HO) to maintain low oxidative damage in plants exposed to environmental stress. This study aimed to clone CAT genes from Citrus sinensis cv. "Oita 4" and analyze their expression patterns in response to environmental stress, exogenous abscisic acid (ABA), and arbuscular mycorrhizal fungal inoculation. Two CAT genes, CitCAT1 (NCBI accession: PP067858) and CitCAT2 (NCBI accession: PP061394) were cloned, and the open reading frames of their proteins were 1479 bp and 1539 bp, respectively, each encoding 492 and 512 amino acids predicted to be localized in the peroxisome, with CitCAT1 being a stable hydrophilic protein and CitCAT2 being an unstable hydrophilic protein. The similarity of their amino acid sequences reached 83.24%, and the two genes were distantly related. Both genes were expressed in stems, leaves, flowers, and fruits, accompanied by the highest expression in mature leaves. In addition, CitCAT1 expression was mainly up-regulated by high temperatures (37 °C), exogenous ABA, and PEG stress within a short period of time, whereas CitCAT2 expression was up-regulated by exogenous ABA and low-temperature (4 °C) stress. Low temperatures (0 °C) for 12 h just up-regulated CitCAT2 expression in Diversispora versiformis-inoculated plants, and D. versiformis inoculation up-regulated CitCAT2 expression, along with lower hydrogen peroxide and malondialdehyde levels in mycorrhizal plants at low temperatures. It is concluded that CitCAT2 has an important role in resistance to low temperatures as well as mycorrhizal enhancement of host resistance to low temperatures.
CitCAT1 和 CitCAT2 在成熟叶片中被克隆并高度表达。高温上调 CitCAT1 的表达，而低温和 Diversispora versiformis 上调 CitCAT2 的表达，从而保持低氧化损伤。过氧化氢酶（CAT）是一种四聚体血红素酶，可去除过氧化氢（HO），以维持暴露于环境胁迫下的植物的低氧化损伤。本研究旨在从柑橘品种“大分 4 号”中克隆 CAT 基因，并分析其在应对环境胁迫、外源脱落酸（ABA）和丛枝菌根真菌接种时的表达模式。克隆了两个 CAT 基因，CitCAT1（NCBI 登录号：PP067858）和 CitCAT2（NCBI 登录号：PP061394），其蛋白质的开放阅读框分别为 1479bp 和 1539bp，分别编码 492 和 512 个氨基酸，预测定位于过氧化物酶体中，CitCAT1 是一种稳定的亲水蛋白，CitCAT2 是一种不稳定的亲水蛋白。它们的氨基酸序列相似性达到 83.24%，这两个基因在进化上相距较远。这两个基因都在茎、叶、花和果实中表达，在成熟叶片中表达最高。此外，CitCAT1 的表达主要受高温（37°C）、外源 ABA 和 PEG 胁迫的短期诱导上调，而 CitCAT2 的表达受外源 ABA 和低温（4°C）胁迫的诱导上调。低温（0°C）处理 12h 仅上调 Diversispora versiformis 接种植物中 CitCAT2 的表达，Diversispora versiformis 接种上调 CitCAT2 的表达，同时降低低温下丛枝菌根植物的过氧化氢和丙二醛水平。综上所述，CitCAT2 在低温抗性以及丛枝菌根增强宿主对低温的抗性方面具有重要作用。
