[대학원 생명과학과 세미나 안내]
연사 : Zheng-Yi Xu 교수 (Northeast Normal University)
연제 : A DNA Methylation Reader/Chaperone Regulator/Transcription Factor Complex Activates OsHKT1;5 Expression during Salinity Stress
일시 : 2020년 6월 26일 (금) 오후 5시
장소 : 온라인 화상 강의로 진행됩니다.
초청교수 : 우재성 교수
Irrigated lands are increasingly salinized, which adversely affects agricultural productivity. To respond to high sodium (Na+) concentrations, plants harbor multiple Na+-transport systems. Rice high-affinity potassium (K+) transporter 1;5 (OsHKT1;5), a Na+-selective transporter, is essential for maintaining K+/Na+ homeostasis under salt stress. However, the mechanism underlying the regulation of OsHKT1;5 expression remains unknown. Here, we present evidence that a protein complex consisting of OsBAG4, OsMYB106 and OsSUVH7 plays a crucial role in OsHKT1;5 expression in response to salt stress. We isolated a salt stress-sensitive mutant osbag4-1 that also showed significantly reduced expression of OsHKT1;5 as well as reduced K+ and elevated Na+ levels in shoots. Using comparative interactomics, we isolated two OsBAG4-interacting proteins, OsMYB106 (a MYB transcription factor) and OsSUVH7 (a DNA methylation reader) which were crucial for the OsHKT1;5 expression. OsMYB106 and OsSUVH7 bound to the MYB-binding cis-element (MYBE) and the miniature inverted-repeat transposable element (MITE) located upstream of the MYBE, respectively, in the promoter of OsHKT1;5. OsBAG4 functioned as a bridge between OsSUVH7 and OsMYB106 to facilitate the binding of OsMYB106 to the consensus MYBE in the OsHKT1;5 promoter, thereby activating the OsHKT1;5 expression. Elimination of the MITE or knockout of OsMYB106 and OsSUVH7 decreased OsHKT1;5 expression and increased salt sensitivity. Our findings reveal a novel transcriptional complex, consisting of a DNA methylation reader, a chaperone regulator, and a transcription factor, that regulates the expression of OsHKT1;5 during salinity stress.