Studies on the Development of Environmental Stress Resistance in Land Plants Through Ethylene and ABA Signal Transduction Regulation from an Evolutionary Perspective

Extensive molecular genetic studies have demonstrated the basic ethylene signaling pathway. In response to ethylene, the CTR1 protein is inactivated, leading to reduced phosphorylation and increased accumulation of EIN2. Subsequently, EIN2-CEND translocates into the nucleus and indirectly activates central transcription factors in ethylene signaling. However, the biological functions of ethylene and its detailed regulatory mechanism have not been clearly revealed in bryophytes, known as early land plants. Thus, I would like to find answers to the following questions: 1) When did ethylene, a gaseous hormone, begin to play various roles as a phytohormone to modulate the biological processes in plants during their evolution, including the terrestrialization of plants? 2) When did the critical components of the ethylene signaling pathway acquire their unique roles during plant evolution? 3) Did functional cross-talk between ABA and ethylene hormones exist during the early evolution of plants? In particular, I will focus on unveiling whether the transmission mechanism of ethylene signals to the nucleus changed and developed during plant evolution.