Ohkmae K. Park

The nucleus is the subcellular organelle that contains nearly all the genetic information required for the regulated expression of cellular proteins. In this study, we comprehensively characterized the Arabidopsis nuclear proteome. Nuclear proteins were isolated and analyzed using two-dimensional (2D) gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Approximately 500-700 spots were detected in reference 2D gels of nuclear protei

Systemic resistance is induced by necrotizing pathogenic microbes and non-pathogenic rhizobacteria and confers protection against a broad range of pathogens. Here we show that Arabidopsis GDSL LIPASE-LIKE 1 (GLIP1) plays an important role in plant immunity, eliciting both local and systemic resistance in plants. GLIP1 functions independently of salicylic acid but requires ethylene signaling. Enhancement of GLIP1 expression in plants increases resistance to pathogens including Alternaria brassici

The tracheary elements (TEs) of the xylem serve as the water-conducting vessels of the plant vascular system. To achieve this, TEs undergo secondary cell wall thickening and cell death, during which the cell contents are completely removed. Cell death of TEs is a typical example of developmental programmed cell death that has been suggested to be autophagic. However, little evidence of autophagy in TE differentiation has been provided. The present study demonstrates that the small GTP binding pr

Annexins are Ca2+--and phospholipid-binding proteins that form an evolutionarily conserved multigene family throughout the animal and plant kingdoms. Two annexins, AnnAt1 and AnnAt4, have been identified as components in osmotic stress and abscisic acid signaling in Arabidopsis. Here, we report that AnnAt1 and AnnAt4 regulate plant stress responses in a light-dependent manner. The single-mutant annAt1 and annAt4 plants showed tolerance to drought and salt stress, which was greatly enhanced in do

Hypersensitive response (HR) is a form of programmed cell death (PCD) and the primary immune response that prevents pathogen invasion in plants. Here, we show that a microRNAmiR164 and its target gene NAC4 (At5g07680), encoding a NAC transcription factor, play essential roles in the regulation of HR PCD in Arabidopsis thaliana. Cell death symptoms were noticeably enhanced in NAC4-overexpressing (35S:NAC4) and mir164 mutant plants in response to avirulent bacterial pathogens. NAC4 expression was

Lignin, a major component of the secondary cell wall, is important for plant growth and development. Moreover, lignin plays a pivotal role in plant innate immunity. Lignin is readily deposited upon pathogen infection and functions as a physical barrier that limits the spread of pathogens. In this study, we show that an Arabidopsis MYB transcription factor MYB15 is required for the activation of lignin biosynthesis genes such as <i>PAL</i>, <i>C4H</i>, <i>4CL</i>, <i>HCT</i>, <i>C3'H</i>, <i>COMT

Receptor-like kinases are important signaling components that regulate a variety of cellular processes. In this study, an Arabidopsis cDNA microarray analysis led to the identification of the cysteine-rich receptor-like kinase CRK36 responsive to the necrotrophic fungal pathogen, <i>Alternaria brassicicola</i>. To determine the function of <i>CRK36</i> in plant immunity, T-DNA-insertion knockdown (<i>crk36</i>) and overexpressing (<i>CRK36OE</i>) plants were prepared. <i>CRK36OE</i> plants exhib

Proteomics is a leading technology for the high-throughput analysis of proteins on a genome-wide scale. With the completion of genome sequencing projects and the development of analytical methods for protein characterization, proteomics has become a major field of functional genomics. The initial objective of proteomics was the large-scale identification of all protein species in a cell or tissue. The applications are currently being extended to analyze various functional aspects of proteins suc

The gaseous plant hormone ethylene is a key signaling molecule regulating plant growth, development, and defense against pathogens. Octadecanoid-responsive arabidopsis 59 (ORA59) is an ethylene response factor (ERF) transcription factor and has been suggested to integrate ethylene and jasmonic acid signaling and regulate resistance to necrotrophic pathogens. Here we screened for ORA59 interactors using the yeast two-hybrid system to elucidate the molecular function of ORA59. This led to the iden

The evolutionary plant-pathogen arms race has equipped plants with the immune system that can defend against pathogens. Pattern-triggered immunity and effector-triggered immunity are two major branches of innate immunity that share immune responses, including oxidative bursts, transcriptional reprogramming, and cell wall modifications such as lignin deposition. In a previous study, we reported that lignin rapidly accumulates in pathogen-infected <i>Arabidopsis</i> leaves and acts as a mechanical

Arabidopsis GDSL lipase 1 (GLIP1) has been shown to modulate systemic immunity through the regulation of ethylene signaling components. Here we demonstrate that the constitutive triple response mutant ctr1-1 requires GLIP1 for the ethylene response, gene expression, and pathogen resistance. The glip1-1 mutant was defective in induced resistance following primary inoculation of necrotrophic pathogens, whereas GLIP1-overexpressing plants showed resistance to multiple pathogens. Necrotrophic infect

Stat3alpha and Stat3beta are two Stat3 isoforms with marked quantitative differences in their DNA binding activities. To examine the molecular basis of the differential DNA binding activities, we measured DNA binding strength and dimer stability, two possible mechanisms responsible for these differences. Stat3alpha and Stat3beta showed no difference in DNA binding strength, i.e. they had similar association and dissociation rates for DNA binding. However, competition analyses performed with diss