Eun Jung Suh

Flowering Time Genes and Application in Crops

The floral transition from vegetative to reproductive development is a very important step in the life cycle of a flowering plant. Extensive genetic analysis using model plant Arabidopsis has revealed that multiple pathways, as photoperiod, vernalization, autonomous pathway, gibberellin, and endogenous cues in a specific season are involved in the flowering time. Many genes that control flowering time have been identified. Among these, vernalization and autonomous pathway are mediated by the regulation of the floral repressor FLC. These pathways depend on a multitude of factors involved in RNA processing and epigenetic regulation that regulate the floral repressor FLC. FLD, FVE, VIN3, VRN1, VRN2, and FRI are involved in chromatin-remodeling, FY in RNA processing, and FCA, FPA, and FLK in RNA binding. In photoperiod pathway, the flowering induction signals from light are integrated by floral integrator FT. FT is induced by the CO and induces the expression of floral meristem identity gene AP1, which control floral organ development. Controlling the timing of floral transition is essentially important in crop plants for high agricultural productivity and adaptation to environmental changes. Currently, a growing number of genes related to flowering have been studied in crop plants. This article reviews the key regulators in floral regulatory pathways and application of these genes to modification of flowering time in crop plants.

Callus induction and plant regeneration from immature zygotic embryos of various maize genotypes (Zea mays L.)

옥수수의 최적 조직 배양 조건을 확립하기 위하여 옥수수 국내 5 계통과 국외 11 계통 총 16 계통을 포트와 포장 재배하여 미성숙 배를 분리하여 배발생 캘러스 유도 및 식물체 재분화율을 조사하였다. MS 배지에 auxin으로 1.5 mg/L Dicamba와 0.5 mg/L 2,4-D 가 첨가된 배지에서 캘러스 형성은 본 실험에 사용된 옥수수 ...

Effects of Brassica rapa SHI-RELATED SEQUENCE overexpression on petunia growth and development

SHI-RELATED SEQUENCE (SRS) genes are plant-specific transcription factors that contain a zinc-binding RING finger motif, which play a critical role in plant growth and development. Among Brassica rapa SRS genes, BrSRS7 and BrLRP1 genes, isolated from shoot apical regions are important regulators of plant growth and development. In order to explore the function of BrSRS genes in horticultural plant growth and development, two constructs containing BrSRS7 and BrLRP1 under the control of a cauliflower mosaic virus 35S promoter were introduced into petunia by Agrobacterium-mediated transformation. The resulting transgenic plants were dwarf and compact plants with reduced plant height and diameter. Additionally, these transgenic plants had upward-curled leaves of narrow width and short internodes. Interestingly, the flower shapes of petunia were different among transgenic plants harboring different kinds of SRS genes. These phenotypes were stably inherited through generations T2 and T3. Semi-quantitative RT-PCR analyses of transgenic plants revealed that BrSRS7 and BrLRP1 regulate expression of gibberellin (GA)- and auxinrelated genes, PtAGL15- and PtIAMT1-related, involved in shoot morphogenesis. These results indicate that the overexpression of BrSRS7 and BrLRP1 genes suppressed the growth and development of petunia by regulating expression of GA- and auxin-related genes. From these data, we deduce that BrSRS7 and BrLRP1 genes play an important role in the regulation of plant growth and development in petunia. These findings suggest that transformation with the BrSRS genes can be applied to other species as a tool for growth retardation and modification of plant forms.