College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
College of Food and Biological Science and Technology, Wuhan Institute of Design and Sciences, Wuhan, 430070, Hubei, China.
Protoplasma. 2021 Jul;258(4):891-904. doi: 10.1007/s00709-021-01610-8. Epub 2021 Jan 23.
Autophagy is a pathway for the degradation of cytoplasmic components in eukaryotes. In wheat, the mechanism by which autophagy regulates programmed cell death (PCD) is unknown. Here, we demonstrated that short-term waterlogging-induced autophagy inhibited PCD in root cells of wheat. The waterlogging-tolerant wheat cultivar Huamai 8 and the waterlogging-sensitive wheat cultivar Huamai 9 were used as experimental materials, and their roots were waterlogged for 0-48 h. Waterlogging stress increased the number of autophagic structures, the expression levels of autophagy-related genes (TaATG), and the occurrence of PCD in root cells. PCD manifested as morphological changes in the cell nucleus, significant enhancement of DNA laddering bands, and increases in caspase-like protease activity and the expression levels of metacaspase genes. The autophagy promoter rapamycin (RAPA) reduced PCD levels, whereas the autophagy inhibitor 3-methyladenine (3-MA) enhanced them. The expression levels of TaATG genes and the number of autophagic structures were lower in cortex cells than in stele cells, but the levels of PCD were higher in cortex cells. The number of autophagic structures was greater in Huamai 8 than in Huamai 9, but the levels of PCD were lower. In summary, our results showed that short-term waterlogging induced autophagy which could inhibit PCD. Mechanisms of response to waterlogging stress differed between cortex and stele cells and between two wheat cultivars of contrasting waterlogging tolerance.
自噬是真核生物中细胞质成分降解的途径。在小麦中，自噬调节程序性细胞死亡（PCD）的机制尚不清楚。在这里，我们证明了短期水涝诱导的自噬抑制了小麦根细胞中的 PCD。利用耐水涝小麦品种华麦 8 和水涝敏感小麦品种华麦 9 作为实验材料，将其根水涝处理 0-48 小时。水涝胁迫增加了自噬结构的数量、自噬相关基因（TaATG）的表达水平以及根细胞中 PCD 的发生。PCD 表现为细胞核形态变化、DNA 梯带明显增强以及半胱天冬酶样蛋白酶活性和 metacaspase 基因表达水平升高。自噬促进剂雷帕霉素（RAPA）降低了 PCD 水平，而自噬抑制剂 3-甲基腺嘌呤（3-MA）则增强了 PCD 水平。皮层细胞中的 TaATG 基因表达水平和自噬结构数量低于中柱细胞，但 PCD 水平高于中柱细胞。华麦 8 中的自噬结构数量大于华麦 9，但 PCD 水平较低。综上所述，我们的结果表明，短期水涝诱导的自噬可以抑制 PCD。对水涝胁迫的反应机制在皮层细胞和中柱细胞以及两种耐水涝性不同的小麦品种之间存在差异。
