Wei Shan, first author of MaXB3 Modulates MaNAC2, MaACS1 and MaACO1 Stability to Repress Ethylene Biosynthesis during Banana Fruit Ripening
Current Position: Lecturer, College of Horticulture, South China Agricultural University
Education: B. S., M.S. and D. S. in Agriculture from South China Agricultural University
Non-scientific Interests: running, movies, cooking
Brief Bio: I did my masters and doctoral degrees in the lab of Prof. Jian-ye Chen and Prof. Wang-jin Lu, at South China Agricultural University, where I investigated the mechanism concerning NAC transcription factors (TFs) in regulation of banana ripening. At that time, we identified two banana NAC TFs, MaNAC1 and MaNAC2, which were found to be involved in fruit ripening through their interactions with ethylene signalling component MaEIL5. After graduation, I worked in South China Agricultural University and continued my research in the same group. Currently, I am studying the possible roles of E3 ubiquitin ligases in banana fruit ripening and quality formation. In a yeast two-hybrid screen using MaNAC2 as bait, we identified a RING-Type E3 Ligase MaXB3. Further experiments revealed that MaXB3 promoted the degradation of MaNAC2 through the ubiquitin-proteasome pathway, thus suppressing MaNAC2-mediated transcriptional repression on ripening-related genes. Additionally, MaXB3 ubiquitinated and degraded two key enzymes in ethylene biosynthesis, MaACS1 and MaACO1, to negatively regulate ethylene biosynthesis. Finally, we established a regulatory cascade involving MaXB3, MaNAC2, MaACS1 and MaACO1 that controls ethylene biosynthesis during banana ripening. Future direction may focus on the ubiquitination of TFs in more details, to further reveal the controlling mechanisms underlying banana fruit ripening at transcriptional and post-translational levels.