서강대학교

초록/요약

Plants are sessile organisms that are constantly exposed to diverse environmental factors. To adapt to diverse environmental stimuli, the development process in plants is an ongoing process that continues postembryonically, which is differs from that in animals. The continous development is accomplished via apical meristem and lateral meristem. Acpial meristem is localized in the shoot and root tip and responsible for primary growth (lengthening of shoots and roots). Lateral meristem occurs at cambium and contributes to the widening and thickening of plants. Plant structure and morphology affect plant biomass and yield. In order to understand plant development, I isolated mutants showed alterations in development. sagl1 (small and glossy leaves1), mfo1 (multifolia1), and osrel2 (oriza sativa ramosa1 enhancer locus2) were isolated and characterized. sagl1 showed defects in leaf development such as small, glossy, thick, dark green and upright leaves. Also, sagl1 showed high accumulation of anthocyanin and lignins, which are derived from phenylpropanoid biosynthesis pathway, while SAGL1OE showed low accumulation of anthocyanin and lignins. Phenylpropanoid pathway starts with conversion of L-phenylalanine into trans-cinnamic acid by phenylalanine ammonia-lyase (PAL). SAGL1, a Kelch repeat F-box protein, interacts with PAL1 protein for proteasome-mediated degradation and indirectly regulates the ANS expression, which is one of the central enzymes for anthocyanin and proanthocyanidins biosynthesis. This study revealed that SAGL1 is a regulator of phenylpropanoid biosynthesis and contributes to plant development and growth. Another Arabidopsis mutant mfo1 (multifolia1) with mutant phenotypes of small size and increased leaf number had a mutation in a glutamate carboxypeptidase and was an allele of a previously reported mutant, amp1-1 (altered meristem program1-1). Despite the similarly increased number of leaves, mfo1 and amp1-1 showed different bolting time; mfo1 bolted as same time as its background Ler while amp1-1 bolted earlier than its background Col. This study suggests the existence of genetic modifier(s) differently function in each ecotype in the presence of mfo1/amp1 mutation. osrel2 rice mutant displayed defects in panicle heading, sterile lemma elongation, and panicle branching development. OsREL2 is orthologous to the Arabidopsis shoot apical meristem fate-determining TOPLESS and important in axillary branch development. This study suggests that OsREL2 is involved in branch formation regulations presumably by suppressing primary branch formation and promoting secondary branch formation.