Suk-Whan Hong

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Seed germination is regulated by endogenous hormonal cues and external environmental stimuli such as water, low temperature, and light. After germination, the young seedling must rapidly establish its root system and the photoautotrophic capability appropriate to its surrounding environment. Light and the phytohormone abscisic acid (ABA) both regulate seed(More)
We have defined amino acids important for function of the Arabidopsis thaliana Hsp100/ClpB chaperone (AtHsp101) in acquired thermotolerance by isolating recessive, loss-of-function mutations and a novel semidominant, gain-of-function allele [hot1-4 (A499T)]. The hot1-4 allele is unusual in that it not only fails to develop thermotolerance to 45 degrees C(More)
The Casein lytic proteinase/heat shock protein 100 (Clp/Hsp100) proteins are chaperones that act to remodel/disassemble protein complexes and/or aggregates using the energy of ATP. In plants, one of the best-studied proteins from this family is cytosolic ClpB1 (At1g74310), better known in Arabidopsis as AtHsp101, which is a heat shock protein required for(More)
In response to environmental challenges, plant cells activate several signaling pathways that trigger the expression of transcription factors. Arabidopsis MYB60 was reported to be involved in stomatal regulation under drought conditions. Here, two splice variants of the MYB60 gene are shown to play a crucial role in stomatal movement. This role was(More)
Plants acquire thermotolerance to lethal high temperatures if first exposed to moderately high temperature or if temperature is increased gradually to an otherwise lethal temperature. We have taken a genetic approach to dissecting acquired thermotolerance by characterizing loss-of-function thermotolerance mutants in Arabidopsis. In previous work, we(More)
To evaluate the genetic control of stress responses in Arabidopsis, we have analyzed a mutant (uvh6-1) that exhibits increased sensitivity to UV light, a yellow-green leaf coloration, and mild growth defects. We have mapped the uvh6-1 locus to chromosome I and have identified a candidate gene, AtXPD, within the corresponding region. This gene shows sequence(More)
Various Myb proteins have been shown to play crucial roles in plants, including primary and secondary metabolism, determination of cell fate and identity, regulation of development and involvement in responses to biotic and abiotic stresses. The 126 R2R3 Myb proteins (with two Myb repeats) have been found in Arabidopsis; however, the functions of most of(More)
Expansins are cell wall loosening proteins that appear to permit the microfibril matrix network to slide in growing plant cell walls, thereby enabling the wall to expand. To scrutinize possible impacts on plant growth and development when expansins are over-expressed, we characterized phenotypic alterations of the transgenic plants that constitutively(More)
Photomorphogenesis is an essential program in plant development. This process is effected by the balanced cooperation of many factors under light and dark conditions. In a previous study, we showed that MYB hypocotyl elongation-related (MYBH) is involved in cell elongation. To expand our understanding of MYBH function, we performed a yeast two-hybrid assay(More)
Our results showed the histone deacetylase inhibitors (HDIs) control root development in Arabidopsis via regulation of PIN1 degradation. Epigenetic regulation plays a crucial role in the expression of many genes in response to exogenous or endogenous signals in plants as well as other organisms. One of epigenetic mechanisms is modifications of histone, such(More)