Physiological and transcriptomic analysis revealed that the accumulation of reactive oxygen species caused the low temperature sensitivity of Liriodendron × sinoamericanum.

Liriodendron × sinoamericanum is widely cultivated in southern China as an excellent wood and garden ornamental trees. However, its intolerance to low temperature limits its application to high latitudes. Understanding the molecular mechanism of low temperature sensitivity of Liriodendron × sinoamericanum is very important for its further application. In this study, combined with physiological and transcriptomic analysis, it was revealed that low temperature stress can lead to water loss and decreased photosynthetic capacity of Liriodendron × sinoamericanum leaves. The accelerated accumulation of reactive oxygen species (ROS) caused by the imbalance of cell REDOX homeostasis is one of the important reasons for the low temperature sensitivity. Further analysis showed that several transcription factors could be involved in regulating the synthesis and degradation of ROS, among which LsNAC72 and LsNAC73a could regulate the accumulation of O2- and H2O2 in leaves by affecting the expression level of LsAPX, LsSOD, LsPAO, and LsPOD.