Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
Physiol Plant. 2024 Jul-Aug;176(4):e14409. doi: 10.1111/ppl.14409.
Plants have evolved various mechanisms to adapt to the ever-changing external environment. Autophagy is one such mechanism and has been suggested to play a key role in responding to and adapting to abiotic stresses in plants. However, the role of autophagy in adaptation to cold and freezing stresses remains to be characterized in detail. Here, we investigated the role of autophagy in the low-temperature response of Arabidopsis using atg mutants. Both the atg5-1 and atg10-1 mutants exhibited normal freezing tolerance, regardless of cold acclimation. A comparison of fresh weights indicated that the difference in growth between the wild-type and atg plants under cold conditions was rather small compared with that under normal conditions. Analysis of COLD-REGULATED gene expression showed no significant differences between the atg mutants and wild type. Treatment with 3-methyladenine, an inhibitor of autophagy, did not impair the induction of COR15Apro::LUC expression upon exposure to low temperature. Evaluation of autophagic activity using transgenic plants expressing RBCS-mRFP demonstrated that autophagy was rarely induced by cold exposure, even in the dark. Taken together, these data suggest that autophagy is suppressed by low temperatures and is dispensable for cold acclimation and freezing tolerance in Arabidopsis.
植物已经进化出各种机制来适应不断变化的外部环境。自噬就是其中一种机制，它被认为在植物应对和适应非生物胁迫中起着关键作用。然而，自噬在适应低温和冷冻胁迫中的作用仍需要详细研究。在这里，我们使用 atg 突变体研究了自噬在拟南芥低温反应中的作用。atg5-1 和 atg10-1 突变体在冷驯化的情况下都表现出正常的抗冻性。鲜重比较表明，与正常条件下相比，低温条件下野生型和 atg 植物之间的生长差异较小。对 COLD-REGULATED 基因表达的分析表明，atg 突变体与野生型之间没有显著差异。用自噬抑制剂 3-甲基腺嘌呤处理，低温暴露时 COR15Apro::LUC 表达的诱导不受影响。使用表达 RBCS-mRFP 的转基因植物评估自噬活性表明，即使在黑暗中，自噬也很少被低温诱导。综上所述，这些数据表明，低温抑制自噬，并且在拟南芥的低温驯化和抗冻性中是可有可无的。
