• The Korean Journal of Mycology
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• v.20 no.3
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• pp.222-228
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• 1992

Pleurotus florida was transformed by complementation of auxotrophic mutant using chimeric plasmid containing Flammulina velutipes leu 2 gene and pBR 322 replicon. Mycelial morphology of transformants was grown and compared on mushroom complete and minimal medium. Transformants were mated with monokaryon and their genetic recombination was investigated for the morphology of fruitbody and spore analysis. $Leu^+$ transformant showed same mating type of $A_1B_1$ as to the untransformed mutant. The transformant and the untransformed mutant were mated with monokaryon of which mating type is $A_2B_1$, respectively. Although fruitbody of the untransformed mutant was not produced, $leu^+$ transformant produced fruitbody. Spore analysis showed that leucine requiring spores from fruitbody of $leu^+$ transformant were diminished when compared with those of untransformed mutant.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.2
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• pp.100-110
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• 2006

A mutant of Potato vims Y (PVY) was occurred in PVY resistance flue-cured tobacco breeding line KF0402 $(TC1146{\times}KF117)$ showing vein necrosis at Suwon in Korea. This isolate, PVY-SWM, was differentiated from other PVY based on biological properties and nucleotide sequence analyses of coat protein gene. PVY-SWM caused typical symptoms on 21 indicator plants as compared to the PVY-TOJC37. Remarkably, the PVY-SWM induced distinctly different symptom of systemic vein necrosis on tobacco cultivars V.SCR, PBD6, TN86, TN90, Virgin A Mutant (VAM), Wislica, NC744, KB108 and KB111, which were reported to have the recessive potyvirus resistance gene va. In RT-PCR assays with specific primers for detection of PVY, a single band of about 800bp in length was produced. The amplified DNA was cloned and the nucleotide sequence was determined. The coat protein gene of PVY-SWM showed 88.4%-99.0% and 92.5%-98.5% identities to the 12 different PVY isolates of Genbank Database at the nucleotide and amino acidi respectively. Multiple alignments as well as cluster dendrograms of PVY-SWM isolate revealed close phylogenetic relationship to the $PVY^{NTN}$ subgroup.

• BMB Reports
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• v.33 no.3
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• pp.256-262
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• 2000

In this study the disassembly process of chlorophyII (ChI)protein complexes of a stay-green mutant (ore10 of Arabidopsis thaliana) was investigated during the dark incubation of detached leaves. During this dark-induced senescence (DIS), the Chi loss was delayed in the mutant, while the photochemical efficiency of photosystem II (PSII) or Fv/Fm was accelerated when compared with the wild type (WT) leaves. This indicates that the decrease in Fv/Fm is a separate process and not causally-linked to the degradation of Chi during DIS of Arabidopsis leaves. In the native green gel electrophoresis of the Chi-protein complexes, which was combined with an additional twodimensional SDS-PAGE analysis, the delayed senescence of this mutant was characterized by the appearance of an aggregate at 1 d or 2 d, as well as very stable light harvesting complex II (LHCII) trimers until 5 d after the start of DIS. The polypeptide composition of the aggregates varied during the whole DIS at 5 d. Dl protein appeared to be missing in the aggregates. This result supports the idea of a faster depletion of functional PSH in the mutants compared with WT, as suggested by the earlier reduction of Fv/Fm and the stable Chl a/b ratio in the mutants. At 5 d, the WT leaves also often showed aggregates, but the polypeptide composition was different from those of ore10. The results presented suggest that the formation of aggregates, or stable LHCII trimers in the stay-green mutants, is a way to structurally protect Chi-protein complexes from serious proteolytic degradation. Detailed disassembly processes of Chi-protein complexes in WT and ore10 mutants are discussed.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.314-322
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• 2020

Interplay between histone acetylation and deacetylation is one of the key components in epigenetic regulation of transcription. Here we report the requirement of MoHDA1-mediated histone deacetylation during asexual development and pathogenesis for the rice blast fungus, Magnaporthe oryzae. Structural similarity and phylogenetic analysis suggested that MoHDA1 is an ortholog of Saccharomyces cerevisiae Hda1, which is a representative member of class II histone deacetylases. Targeted deletion of MoHDA1 caused a little decrease in radial growth and large reduction in asexual sporulation. Comparison of acetylation levels for H3K9 and H3K14 showed that lack of MoHDA1 gene led to significant increase in H3K9 and H3K14 acetylation level, compared to the wild-type and complementation strain, confirming that it is a bona fide histone deacetylase. Expression analysis on some of the key genes involved in asexual reproduction under sporulation-promoting condition showed almost no differences among strains, except for MoCON6 gene, which was up-regulated more than 6-fold in the mutant than wild-type. Although the deletion mutant displayed little defects in germination and subsequent appressorium formation, the mutant was compromised in its ability to cause disease. Wound-inoculation showed that the mutant is impaired in invasive growth as well. We found that the mutant was defective in appressorium-mediated penetration of host, but did not lose the ability to grow on the media containing H₂O₂. Taken together, our data suggest that MoHDA1-dependent histone deacetylation is important for efficient asexual development and infection of host plants in M. oryzae.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.355-363
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• 2020

Bacterial traits for virulence of Ralstonia solanacearum causing lethal wilt in plants were extensively studied but are not yet fully understood. Other than the known virulence factors of Ralstonia solanacearum, this study aimed to identify the novel gene(s) contributing to bacterial virulence of R. solanacearum. Among the transposon-inserted mutants that were previously generated, we selected mutant SL341F12 strain produced exopolysaccharide equivalent to wild type strain but showed reduced virulence compared to wild type. In this mutant, a transposon was found to disrupt the murI gene encoding glutamate racemase which converts L-glutamate to D-glutamate. SL341F12 lost its motility, and its virulence in the tomato plant was markedly diminished compared to that of the wild type. The altered phenotypes of SL341F12 were restored by introducing a full-length murI gene. The expression of genes required for flagella assembly was significantly reduced in SL341F12 compared to that of the wild type or complemented strain, indicating that the loss of bacterial motility in the mutant was due to reduced flagella assembly. A dramatic reduction of the mutant population compared to its wild type was apparent in planta (i.e., root) than its wild type but not in soil and rhizosphere. This may contribute to the impaired virulence in the mutant strain. Accordingly, we concluded that murI in R. solanacearum may be involved in controlling flagella assembly and consequently, the mutation affects bacterial motility and virulence.

• Archives of Pharmacal Research
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• v.28 no.9
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• pp.1073-1078
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• 2005

A presenilin 2 mutation is believed to be involved in the development of Alzheimer's disease. In addition, transgenic mice with a presenilin 2 mutation have been reported to have learning and memory impairments. In this study, exposing PC12 cells expressing mutant presenilin 2 to $50{\mu}M\;A{\beta}_{25-35},\;30mM$ L-glutamate and $50{\mu}M\;H_2O_2$ caused a significant increase in acetylcholine esterase activity. An in vivo study revealed high levels of this enzyme activity in the mutant presenilin 2 transgenic brains compared with the wild type presenilin 2 transgenic and non-transgenic samples. These results suggest that a mutant presenilin 2-induced neurodegeneration in Alzheimer's disease might be involved in the increase in acetylcholinesterase activity. These findings might help in the development of an appropriate therapeutic intervention targeting mutant presenilin 2-induced Alzheimer's disease.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.110-110
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• 2017

Stomata are the main gateways for water and air transport between leaves and the environment. Inward-rectifying potassium channels regulate photo-induced stomatal opening. Rice contains three inward rectifying shaker-like potassium channel proteins, OsKAT1, OsKAT2 and OsKAT3. Among these, only OsKAT2 is specifically expressed in guard cells. Here, we investigated the functions of OsKAT2 in stomatal regulation using three dominant negative mutant proteins, OsKAT2(T235R), OsKAT2(T285A) and OsKAT2(T285D), which are altered in amino acids in the channel pore and at a phosphorylation site. Yeast complementation and patch clamp assays showed that all three mutant proteins lost channel activity. However, among plants overexpressing these mutant proteins, only plants overexpressing OsKAT2(T235R) showed significantly less water loss than the control. Moreover, overexpression of this mutant protein led to delayed photo-induced stomatal opening and increased drought tolerance. Our results indicate that OsKAT2 is an inward-rectifying shaker-like potassium channel that mainly functions in stomatal opening. Interestingly, overexpression of OsKAT2(T235R) did not cause serious defects in growth or yield in rice, suggesting that OsKAT2 is a potential target for engineering plants with improved drought tolerance without yield penalty.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.90-90
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• 2017

Regulation of seed dormancy is important in many grains to prevent pre-harvest sprouting. To identify and understand the gene related to seed dormancy regulation, we have screened for viviparous phenotypes of rice mutant lines generated by insertion of Ds transposon in a Korean Japonica cultivar (Dongjin) background. One of the mutants, which represented viviparous phenotype, was selected for further seed dormancy regulation studies and designated dor1. The dor1 mutant has single Ds insertion in the second exon of OsDor1 gene encoding glycine-rich protein. The seeds of dor1 mutant showed a higher germination potential and reduced abscisic acid (ABA) sensitivity compared to wild type Dongjin. Over-expression of Dor1 complements the viviparous phenotype of dor1 mutant, indicating that Dor1 function in seed dormancy regulation. Subcellular localization assay of Dor1-GFP fusion protein revealed that the OsDor1 protein mainly localized to membrane and the localization of OsDOR1 was influenced by presence of a giberelin (GA) receptor OsGID1. Further bimolecular fluorescence complementation (BiFC) analysis indicated that OsDOR1 interact with OsGID1. The combined results suggested that OsDOR1 regulates seed dormancy by interacting with OsGID1 in GA response. Additionally, expression of OsDOR1 partially complemented the cold sensitivity of Escherichia coli BX04 mutant lacking four cold shock proteins, indicating that OsDOR1 possessed RNA chaperone activity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.72-72
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• 2017

We found a new stay-green mutant from 'Pyeongwon' which is an early-maturing rice variety in Korea. The mutant showed green leaves after grain ripening period and it maintained higher SPAD value than wild type rice plant and original variety 'Pyeongwon'. The stay-green trait in rice, three genes have been identified up to date. The non-yellow coloring1 (NYC1) gene encodes a chloroplast-localized short-chain dehydrogenase/reductase (SDR) with three transmembrane domains. The non-yellow coloring3 (NYC3) gene encodes a plastid-localizing alpha/beta hydrolase-fold family protein with an esterase/lipase motif. The Sgr gene encodes a novel chloroplast protein and regulates the destabilization of the light-harvesting chlorophyll binding protein (LHCP) complexes of the thylakoid membranes, which is a prerequisite event for the degradation of chlorophylls and LHCPs during senescence. After sequencing the PCR products, we found a single nucleotide variation($A{\rightarrow}T$) in the NYC1 gene, which changes the amino acid lysine to methionine. The NYC1 gene encodes a short-chain dehydrogenase/reductase(SDR) protein. And we confirmed the co-segregation between SNP and stay-green trait from genotyping the progenies of the mutant.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.801-804
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• 2013

The glutathione contents of the selected mutants were investigated and found to be 6.1-15.8 mg/g-DCW. The glutathione content positively correlated with the antioxidant activity of the mutant strains ($R^2$=0.488). Furthermore, the glutathione content of the mutant S. cerevisiae Sa-59 was approximately 38% greater than that of the wild type strain and, therefore, this mutant strain was selected for glutathione production. The volumetric glutathione content in a shaking culture was increased by about 70% compared to the static culture. In addition, the specific glutathione content was increased by ~19%. The volumetric glutathione content and specific glutathione content were increased by approximately 16% and 66%, respectively, when 0.04% glutamate, 0.04% cysteine and 0.04% glycine were added. Furthermore, the highest antioxidant activity was 0.52 as absorbance unit at 700 nm.