[대학원 생명과학과 세미나 안내]
연사 : 서미정 교수 (서강대학교 생명과학과)
연제 : The Arabidopsis SAGL1 E3 Ligase and ECERIFERUM3 Module Regulates Cuticular Wax Biosynthesis in Response to Humidity
일시 : 2019년 6월 7일 (금) 오후 5시
장소 : 하나과학관 A동 B131호
초청교수 : 김정국 교수
Abstract
Cuticular waxes that cover the above-ground parts of land plants are essential for their survival in terrestrial environment. However, little is known about the regulatory mechanisms underlying cuticular wax biosynthesis in response to changes in ambient humidity. Here, we report that SMALL AND GLOSSY LEAVES 1 (SAGL1) Kelch repeat F-box protein mediates proteasome-dependent degradation of ECERIFERUM3 (CER3), a biosynthetic enzyme that is involved in the production of very long chain alkanes, which are the major wax components and thereby negatively regulates cuticular wax biosynthesis in Arabidopsis. Disruption of SAGL1 caused severe growth retardation, enhanced tolerance to drought and increased wax accumulation in stems, leaves, and roots. Cytoplasmic SAGL1 physically interacts with CER3 and targets CER3 for degradation. GUS expression was observed in roots of pSAGL1::GUS plants, but barely detected in their aerial organs. High (>90%) humidity-induced levels of GUS activity and SAGL1 transcripts were reduced by ABA treatment and water-deficit. The levels of SAGL1 were also increased under high humidity and SAGL1 was degraded by the 26S proteasome. SAGL1 regulates the levels of MYC:CER3 proteins in response to humidity changes. This study revealed that the SAGL1-CER3 module negatively regulates Arabidopsis cuticular wax biosynthesis in response to changes to humidity conditions and suggested the importance of permeable cuticle formation in terrestrial plants under high humidity.