Key message

MfLEA3 is involved in protection of catalase activity and confers multiple abiotic stress tolerance.

Abstract

Late embryogenesis abundant (LEA) proteins are involved in plant growth, development and abiotic stress tolerance. A member of group 3 LEA proteins from Medicago sativa subsp. falcata (L.) Arcang, MfLEA3, was investigated in the study. MfLEA3 transcript was induced in response to cold, dehydration, and abscisic acid (ABA), while the cold-induced transcript of MfLEA3 was blocked by pretreatment with inhibitor of ABA synthesis. Constitutive expression of MfLEA3 led to enhanced tolerance to cold, drought, and high-light stress in transgenic tobacco plants. Compared to accumulated reactive oxygen species (ROS) in the wild-type in response to treatments with low temperature, drought, and high light, ROS were not accumulated in transgenic plants. Superoxide dismutase, catalase (CAT), and ascorbate-peroxidase activities were increased in all plants after treatments with the above stresses, while higher CAT activity was maintained in transgenic plants compared with wild-type. However, transcript level of CAT-encoding genes including CAT1, CAT2, and CAT3 showed no significant difference between transgenic plants and wild-type, indicating that the higher CAT activity was not associated with its gene expression. ABA sensitivity and transcripts of several ABA and stress-responsive genes showed no difference between transgenic plant and wild-type, indicating that ABA signaling was not affected by constitutive expression of MfLEA3. The results suggest that MfLEA3 may be involved in the protection of CAT activity and confers multiple abiotic stress tolerance.

中文翻译：

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来自 Medicago falcata (MfLEA3) 的第 3 组 LEA 蛋白的组成型表达增加了转基因烟草的耐寒性和耐旱性。

关键信息

MfLEA3 参与过氧化氢酶活性的保护并赋予多种非生物胁迫耐受性。

抽象的

晚期胚胎发生丰富 (LEA) 蛋白参与植物生长、发育和非生物胁迫耐受性。来自Medicago sativa亚种的第 3 组 LEA 蛋白的成员。falcata (L.) Arcang，MfLEA3，在研究中进行了调查。冷、脱水和脱落酸 (ABA) 会诱导 MfLEA3 转录物，而用 ABA 合成抑制剂预处理会阻断冷诱导的MfLEA3转录物。MfLEA3的组成型表达导致转基因烟草植物对寒冷、干旱和强光胁迫的耐受性增强。与野生型在低温、干旱和强光处理下积累的活性氧（ROS）相比，转基因植物中没有积累活性氧。经上述胁迫处理后，所有植物的超氧化物歧化酶、过氧化氢酶 (CAT) 和抗坏血酸-过氧化物酶活性均增加，而与野生型相比，转基因植物保持较高的 CAT 活性。然而，包括CAT1、CAT2和CAT3在内的 CAT 编码基因的转录水平显示转基因植物和野生型之间没有显着差异，表明较高的CAT活性与其基因表达无关。ABA 敏感性和几个 ABA 和胁迫响应基因的转录本在转基因植物和野生型之间没有差异，表明 ABA 信号传导不受MfLEA3组成型表达的影响。结果表明，MfLEA3 可能参与保护 CAT 活性并赋予多种非生物胁迫耐受性。