PDF(Pubmed)
Abstract：
Recycling of unnecessary or dysfunctional cellular structures through autophagy plays a critical role in cellular homeostasis and environmental resilience. Therefore, the autophagy trait may have been unintentionally selected in wheat breeding programs for higher yields in arid climates. This hypothesis was tested by measuring the response of three common autophagy markers, ATG7, ATG8, and NBR1, to a heat wave under reduced soil moisture content in 16 genetically diverse spring wheat landraces originating from different geographical locations. We observed in the greenhouse trials that ATG8 and NBR1 exhibited genotype-specific responses to a 1 h, 40 °C heat wave, while ATG7 did not show a consistent response. Three genotypes from Uruguay, Mozambique, and Afghanistan showed a pattern consistent with higher autophagic activity: decreased or stable abundance of both ATG8 and NBR1 proteins, coupled with increased transcription of ATG8 and NBR1. In contrast, three genotypes from Pakistan, Ethiopia, and Egypt exhibited elevated ATG8 protein levels alongside reduced or unaltered ATG8 transcript levels, indicating a potential suppression or no change in autophagic activity. Principal component analysis demonstrated a correlation between lower abundance of ATG8 and NBR1 proteins and higher yield in the field trials. We found that (i) the combination of heat and drought activated autophagy only in several genotypes, suggesting that despite being a resilience mechanism, autophagy is a heat-sensitive process; (ii) higher autophagic activity correlates positively with greater yield; (iii) the lack of autophagic activity in some high-yielding genotypes suggests contribution of alternative stress-resilient mechanisms; and (iv) enhanced autophagic activity in response to heat and drought was independently selected by wheat breeding programs in different geographic locations.
摘要：
通过自噬回收不必要或功能失调的细胞结构在细胞稳态和环境恢复力中起着关键作用。因此,在小麦育种计划中，可能无意中选择了自噬性状，以在干旱气候下获得更高的产量。通过测量三种常见自噬标志物的反应来检验这一假设。ATG7，ATG8和NBR1在来自不同地理位置的16个遗传多样性春小麦地方品种的土壤水分含量降低的情况下产生热浪。我们在温室试验中观察到ATG8和NBR1对1小时的基因型特异性反应，40°C的热浪，而ATG7没有表现出一致的反应。来自乌拉圭的三种基因型，莫桑比克,和阿富汗显示出与较高的自噬活性一致的模式：ATG8和NBR1蛋白的丰度降低或稳定，加上ATG8和NBR1的转录增加。相比之下,来自巴基斯坦的三种基因型，埃塞俄比亚,和埃及表现出升高的ATG8蛋白水平以及降低或不变的ATG8转录水平，表明自噬活性的潜在抑制或无变化。主成分分析表明，田间试验中ATG8和NBR1蛋白的丰度较低与产量较高之间存在相关性。我们发现（i）热和干旱的结合仅在几种基因型中激活了自噬，这表明尽管是一种复原机制，自噬是一个对热敏感的过程;(ii)较高的自噬活性与较高的产量呈正相关;(iii)某些高产基因型中缺乏自噬活性提示了其他抗逆机制的贡献;(iv)不同地理位置的小麦育种计划独立选择了响应热和干旱的自噬活性增强。
