Han Yuqing, Luo Fei, Liang Adan, Xu Dongdong, Zhang Hongyi, Liu Tao, Qi Hongyan
College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China.
Key Laboratory of Protected Horticulture of Education of Ministry and Liaoning Province, National & Local Joint Engineering Research Center of Northern Horticultural Facilities Design & Application Technology, Shenyang 110866, China.
Plant Physiol. 2024 Dec 23;197(1). doi: 10.1093/plphys/kiae477.
Cold stress severely restricts the growth and development of cold-sensitive crops. Trehalose (Tre), known as the "sugar of life", plays key roles in regulating plant cold tolerance by triggering antioxidation. However, the relevant regulatory mechanism remains unclear. Here, we confirmed that Tre triggers apoplastic hydrogen peroxide (H2O2) production and thus plays key roles in improving the cold tolerance of melon (Cucumis melo var. makuwa Makino) seedlings. Moreover, Tre treatment can promote the transport of apoplastic H2O2 to the cytoplasm. This physiological process may depend on aquaporins. Further studies showed that a Tre-responsive plasma membrane intrinsic protein 2;3 (CmPIP2;3) had strong H2O2 transport function and that silencing CmPIP2;3 significantly weakened apoplastic H2O2 transport and reduced the cold tolerance of melon seedlings. Yeast library and protein-DNA interaction technology were then used to screen 2 Tre-responsive transcription factors, abscisic acid-responsive element (ABRE)-binding factor 2 (CmABF2) and ABRE-binding factor 3 (CmABF3), which can bind to the ABRE motif of the CmPIP2;3 promoter and activate its expression. Silencing of CmABF2 and CmABF3 further dramatically increased the ratio of apoplastic H2O2/cytoplasm H2O2 and reduced the cold tolerance of melon seedlings. This study uncovered that Tre treatment induces CmABF2/3 to positively regulate CmPIP2;3 expression. CmPIP2;3 subsequently enhances the cold tolerance of melon seedlings by promoting the transport of apoplastic H2O2 into the cytoplasm for conducting redox signals and stimulating downstream antioxidation.
低温胁迫严重限制了冷敏感作物的生长发育。海藻糖（Tre），被誉为“生命之糖”，通过触发抗氧化作用在调节植物耐寒性方面发挥关键作用。然而，相关的调控机制仍不清楚。在此，我们证实Tre触发质外体过氧化氢（H2O2）的产生，从而在提高甜瓜（Cucumis melo var. makuwa Makino）幼苗的耐寒性中发挥关键作用。此外，Tre处理可促进质外体H2O2向细胞质的转运。这一生理过程可能依赖于水通道蛋白。进一步研究表明，一种Tre响应型质膜内在蛋白2;3（CmPIP2;3）具有很强的H2O2转运功能，沉默CmPIP2;3会显著削弱质外体H2O2的转运并降低甜瓜幼苗的耐寒性。随后利用酵母文库和蛋白质 - DNA相互作用技术筛选出2个Tre响应型转录因子，脱落酸响应元件（ABRE）结合因子2（CmABF2）和ABRE结合因子3（CmABF3），它们可以结合到CmPIP2;3启动子的ABRE基序并激活其表达。沉默CmABF2和CmABF3进一步显著提高了质外体H2O2/细胞质H2O2的比例并降低了甜瓜幼苗的耐寒性。本研究发现Tre处理诱导CmABF2/3正向调控CmPIP2;3的表达。CmPIP2;3随后通过促进质外体H2O2转运到细胞质中以传导氧化还原信号并刺激下游抗氧化作用来增强甜瓜幼苗的耐寒性。
