RIKEN Center for Sustainable Resource Science, Plant Genomic Network Research Team, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
Plant Epigenome Regulation Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
Plant Mol Biol. 2022 Sep;110(1-2):131-145. doi: 10.1007/s11103-022-01291-8. Epub 2022 Jun 22.
Ethanol priming induces heat stress tolerance by the stimulation of unfolded protein response. Global warming increases the risk of heat stress-related yield losses in agricultural crops. Chemical priming, using safe agents, that can flexibly activate adaptive regulatory responses to adverse conditions, is a complementary approach to genetic improvement for stress adaptation. In the present study, we demonstrated that pretreatment of Arabidopsis with a low concentration of ethanol enhances heat tolerance without suppressing plant growth. We also demonstrated that ethanol pretreatment improved leaf growth in lettuce (Lactuca sativa L.) plants grown in the field conditions under high temperatures. Transcriptome analysis revealed a set of genes that were up-regulated in ethanol-pretreated plants, relative to water-pretreated controls. Binding Protein 3 (BIP3), an endoplasmic reticulum (ER)-stress marker chaperone gene, was among the identified up-regulated genes. The expression levels of BIP3 were confirmed by RT-qPCR. Root-uptake of ethanol was metabolized to organic acids, nucleic acids, amines and other molecules, followed by an increase in putrescine content, which substantially promoted unfolded protein response (UPR) signaling and high-temperature acclimation. We also showed that inhibition of polyamine production and UPR signaling negated the heat stress tolerance induced by ethanol pretreatment. These findings collectively indicate that ethanol priming activates UPR signaling via putrescine accumulation, leading to enhanced heat stress tolerance. The information gained from this study will be useful for establishing ethanol-mediated chemical priming strategies that can be used to help maintain crop production under heat stress conditions.
乙醇预培养通过未折叠蛋白反应的刺激诱导耐热性。全球变暖增加了农业作物因热应激相关减产的风险。使用安全试剂的化学预培养可以灵活地激活对不利条件的适应性调节反应，是遗传改良适应压力的一种补充方法。在本研究中，我们证明了用低浓度乙醇预处理拟南芥可以增强耐热性而不抑制植物生长。我们还证明了乙醇预处理可以改善在高温条件下生长的生菜（Lactuca sativa L.）植株的叶片生长。转录组分析显示，与水预处理对照相比，乙醇预处理的植物中有一组基因上调。内质网（ER）应激标记伴侣蛋白基因 BIP3 是鉴定出的上调基因之一。通过 RT-qPCR 验证了 BIP3 的表达水平。乙醇通过根系吸收代谢为有机酸、核酸、胺和其他分子，随后腐胺含量增加，这大大促进了未折叠蛋白反应（UPR）信号和高温适应。我们还表明，抑制多胺产生和 UPR 信号会否定乙醇预处理诱导的耐热性。这些发现共同表明，乙醇预培养通过腐胺积累激活 UPR 信号，从而增强耐热性。本研究获得的信息将有助于建立乙醇介导的化学预培养策略，以帮助维持作物在热应激条件下的生产。
