S-Space College of Natural Sciences (자연과학대학) Dept. of Biological Sciences (생명과학부) Theses (Ph.D. / Sc.D._생명과학부)
Effects of Remorins on Root-nodule Development in Soybean and Geminivirus Infection in Arabidopsis
콩의 뿌리혹 발달과 애기장대의 제미니바이러스 감염에 미치는 리모린의 영향
- 자연과학대학 생명과학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (박사)-- 서울대학교 대학원 : 생명과학부, 2014. 8. 안정선.
- Remorin, a plant-specific protein containing variable N-terminal region and conserved C-terminal domain, is known to be involved in various biotic and abiotic stress-response mechanisms, elicited by external stimuli such as host-microbe interactions. However, the roles of remorins in soybean and Arabidopsis have not been fully characterized. Thus, to elucidate their functions, I have focused on the role of GmREM1.1/2.1 and AtREM4s in this study. As mentioned in chapter I, the C-terminal anchor (CA) is essential for the plasma membrane (PM) targeting of GmREM1.1/1.3, whereas the CA of GmREM2.1 does not localize to the PM. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays have shown that remorins are involved in homo- and hetero-oligomeric interaction at the PM. However, they do not seem to interact with GmREM2.1. The difference between GmREM1.1 and GmREM2.1 was elucidated using a genetic approach. The GmREM1.1 promoter is active in the inner cortex of root nodules, whereas the GmREM2.1 promoter is activated in the infected cells. Moreover, unlike the rRNA interference (RNAi) of GmREM1.1, the (RNAi) of GmREM2.1 decreases the extent of nodulation on transgenic roots. These results indicate that GmREM1.1 and GmREM2.1 have distinct molecular characterizations and functions during nodule development. As describe in chapter II, AtREM4.1 and AtREM4.2 had typical characteristics of the remorin molecules, and their expression was dramatically induced by osmotic stress, abscisic acid (ABA), and senescence. During geminivirus infection, the mutant lines of AtREM4s showed a reduced susceptibility, whereas the overexpression lines showed the opposite. In addition, they were both regulated by SnRK1 and by the 26S proteasome. Moreover, the co-expression of AtREM4.1 with transcription factor AtTCP14 led to a BiFC signal in the nucleus. These results suggest that AtREM4s could be involved in a SnRK1-mediated signaling pathway, and that they could play an important role as the positive regulators of cell cycle during geminivirus infections.