S-Space College of Agriculture and Life Sciences (농업생명과학대학) Dept. of Plant Science (식물생산과학부) Theses (Master's Degree_식물생산과학부)
Functional Analysis of Cryptochrome-Interacting Basic-helix-loop-helix1 (OsCIB1) in Controlling Leaf Angle and Grain Size in Rice (Oryza sativa)
벼의 잎 각도와 종자 크기에 관여하는 OsCIB1의 기능연구
- 농업생명과학대학 식물생산과학부
- Issue Date
- 서울대학교 대학원
- rice; Cryptochrome-interacting bHLH1 (OsCIB1); transcription factor; lamina joint; leaf angle; brassinosteroid; cell elongation
- 학위논문 (석사)-- 서울대학교 대학원 : 식물생산과학부, 2017. 2. 백남천.
- Cryptochrome-Interacting basic-helix-loop-helix (CIB), an critical transcription factor in plant, plays important roles associated several development processes, including hypocotyl elongation, flowering, and plastid development. It has been reported that a soybean CIB orthologue gene Cryptochrome-interacting bHLH1 (GmCIB1) promotes leaf senescence by activating transcription of senescence-associated genes such as WRKY DNA BINDING PROTEIN53b (WRKY53b). However, any functions of CIB1 have not been studied or reported yet in rice. In this study, we screened two T-DNA mutants to identify the function of OsCIB1. Especially, a rice gain of function mutant, oscib1-D, displayed wide leaf angles and slender grains, similar to plants with increased brassinosteroid (BR) levels or enhanced BR signaling. qRT-PCR analysis showed that gene in brassinosteroid signaling pathway are upregulated in oscib1-D, but there was no significant difference of the expression level of BR biosynthesis-related genes between WT and oscib1-D. In addition, osicb1-D showed more sensitive phenotype than WT to BR. Histological analysis revealed that increased cell length in adaxial surface of lamina joint is responsible for larger angles. Moreover, expression level of genes involved in cell elongation such as expansins and xyloglucan endotransglycosylase/hydrolase(XTH), two major cell wall-loosening enzymes, was significantly increased in oscib1-D. Thus, these results strongly suggest that OsCIB1 is involved in the BR signaling pathway and determines not only leaf inclination but also grain shape by regulating cell-elongation-related genes.