• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2010.10a
• /
• pp.17-17
• /
• 2010

Rhizobacteria are a diverse group of free-living soil bacteria that live in plant rhizosphere and colonized the root system. Plant growth-promoting rhizobacteria (PGPR) possessing ACC deaminase (ACCD) can reduce ACC and ethylene in plant tissue and mediated the growth of plants under various stresses including salt stress. ACCD decrease ethylene levels in plant tissue that produce high levels of ethylene in tissue via elevated levels of ACC under salt stress. We selected strains of Pseudomonas sp. possessing ACCD activity for their ability to promote plant growth under salt stress from soil sample collected at Byeonsan, Jeonbuk, South Korea. The Pseudomonas strains possessing ACCD increased the rate of the seedling and growth of chinese cabbage seeds under salt stress. We cloned ACCD gene from P.fluorescens and expressed recombinant protein in Escherichia coli. The active form of recombinant ACCD converted ACC to a-ketobutyrate. The in vivo treatment of recombinant ACCD itself increase the rate of the seedling and growth of Chinese cabbage seeds under salt stress. The polyclonal P.fluorescens anti-ACCD antibody specifically reacted with ACCD originated from Pseudomonas. This indicates that the antibody might act as an important indicator for ACCD driven from Pseudomonas exhibiting plant growth-promoting activity. This study will be useful for identification of newly isolated PGPR containing ACCD and exploioting the ACCD activity from PGPR against various biotic and abiotic stresses.

• Korean Journal of Microbiology
• /
• v.54 no.4
• /
• pp.471-473
• /
• 2018

Variovorax sp. PMC12 is a rhizobacterium isolated from tomato rhizosphere and enhanced the plant resistance to abiotic and biotic stresses. Here we present the complete genome sequence of strain PMC12. The genome is comprised of two circular chromosomes harboring 5,873,297 bp and 1,141,940 bp, respectively. A total of 6,436 protein-coding genes, 9 rRNAs, 64 tRNAs, 3 ncRNAs, and 80 pseudogenes were identified. We found genes involved in 1-aminocyclopropane-1-carboxylate (ACC) deaminase, antioxidant activity, phosphate solubilization, and biosynthesis of proline and siderophore. Those genes may be related to capability of improving plant resistance to various stresses including salinity, cold temperature, and phytopathogen.

• 한국균학회소식:학술대회논문집
• /
• 2015.05a
• /
• pp.20-20
• /
• 2015

Endophytic fungi are microorganisms inhabiting living plant tissues without causing apparent harm to the host. They are drawing increasing attention due to their ability to produce various bioactive compounds as well as their effects on host growth and resistance to biotic and abiotic stresses. As a first step to assess biodiversity of plant associated fungi in Korea and the following evaluation on diverse biological activities, we are collecting endophytic fungi from plant in wild followed by systematic long-term storage in liquid nitrogen. Molecular identification using ITS sequences was also incorporated for pure culture by hyphal tip isolation. As of April 2015, about 1,400 fungal strains had been isolated from about 170 plant taxa. Fungal isolates belonging to Pleosporales, Diaporthales, Glomerellales, Hypocreales, and Xylariales were the most abundant. These collections are being used for several complementary researches, including screening of isolates with novel bioactive compounds or conferring drought stress resistance, phylogenetic and genomic study. Genome sequencing was performed for 3 isolates, one Xylaria sp. strain JS573 producing griseofulvin, an antifungal compound, and two Fusarium spp. strains JS626 and JS1030, which are assumed to be new species found in Korea. More detailed analysis on these genomes will be presented. These collections and genome informations will serve as invaluable resources for identifying novel bioactive materials in addition to expand our knowledge on fungal biodiversity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.4
• /
• pp.422-426
• /
• 2009

Sweetpotato is one of the important starch crops, current more considered as an industrial crop rather than food because it has higher starch content (over 80% of biomass), it is used for bio resources for industrial area. In this study, we generated S598A (a mutant gene of oat phytochrome A) sweetpotato plant using Agrobacterium-transformation method. Morphological characteristics of S598A plant were compared with the wild type sweetpotato, S598A had darker green leaves, increased chlorophyll content higher than to two-fold, delayed leaf senescence, shorter plant height (60% shorter than that of the wild type), more number of leaves and petioles about 1.8-fold, shorter petiole length (30% shorter), 1.2-fold more branches and 1.6-fold thicker stem diameters. From this study, S598A plants with such phenotypic characteristics might be able to use the solar energy efficiently, to have increased tolerance to biotic and abiotic stresses and finally to increase productivity (not only starch yield but also root biomass yield). S598A sweetpotato lines are under field trials.

• Plant Biotechnology Reports
• /
• v.4 no.3
• /
• pp.179-183
• /
• 2010

Ethylene is a key gaseous hormone that controls various physiological processes in plants including growth, senescence, fruit ripening, and responses to abiotic and biotic stresses. In spite of some of these positive effects, the gas usually inhibits plant growth. While chemical fertilizers help plants grow better by providing soil-limited nutrients such as nitrogen and phosphate, overusage often results in growth inhibition by soil contamination and subsequent stress responses in plants. Therefore, controlling ethylene production in plants becomes one of the attractive challenges to increase crop yields. Some soil bacteria among plant growth-promoting rhizobacteria (PGPRs) can stimulate plant growth even under stressful conditions by reducing ethylene levels in plants, hence the term "stress controllers" for these bacteria. Thus, manipulation of relevant genes or gene products might not only help clear polluted soil of contaminants but contribute to elevating the crop productivity. In this article, the beneficial soil bacteria and the mechanisms of reduced ethylene production in plants by stress controllers are discussed.

• The Plant Pathology Journal
• /
• v.27 no.3
• /
• pp.272-279
• /
• 2011

Root colonization of Arabidopsis thaliana with Pseudomonas chlororaphis O6 induces systemic tolerance against diverse pathogens, as well as drought and salt stresses. In this study, we demonstrated that 11 genes in the leaves were up-regulated, and 5 genes were down-regulated as the result of three- to five-days root colonization by P. chlororaphis O6. The identified priming genes were involved in cell signaling, transcription, protein synthesis, and degradation. In addition, expression of selected priming genes were induced in P. chlororaphis O6-colonized plants subjected to water withholding. Genes encoding defense proteins in signaling pathways regulated by jasmonic acid and ethylene, such as VSP1 and PDF1.2, were additional genes with enhanced expression in the P. chlororaphis O6-colonized plants. This study indicated that the expression of priming genes, as well as genes involved in jasmonic acid- and ethylene-regulated genes may play an important role in the systemic induction of both abiotic and biotic stress due to root colonization by P. chlororaphis O6.

• The Plant Pathology Journal
• /
• v.27 no.3
• /
• pp.249-256
• /
• 2011

Tall fescue (Schedonorus phoenix Scop.) is resistant to abiotic and biotic stresses through a symbiotic relationship with Neotyphodium coenophialum. However, this endophyte has been considered detrimental since it produces toxic alkaloids to animals. It is vital to understand mutuality between these two to maximize positive impact of the endophyte on agri-ecosystem. Little research has been conducted on endophyte transmission mechanism in planta. To provide basic information related to endophyte transmission, an experiment was conducted to examine the effect of endophyte genotype and water stress on endophyte transmission by imposing soil moisture deficits at different stages of panicle development. There was water stress effect on endophyte frequency but not on concentration, whereas endophyte genotype significantly influenced endophyte concentration in pseudostem of tall fescue at boot stage. Reproductive tillers showed greater endophyte frequency and concentration. Endophyte frequency in florets or seeds depended on position within panicle. There was no drought effect on endophyte concentration, but showed the effect of endophyte genotype on endophyte concentration in florets and seeds. Overall endophyte concentration in seeds was higher. From this study, we may conclude that although water stress reduced endophyte frequency in vegetative tiller, water stress does not have effect on endophyte transmission, suggesting that drought is not an important factor controlling the endophyte transmission from plant to seed. Endophyte genotype and seed position in a panicle affected endophyte transmission, indicating that these two factors are involved in endophyte transmission and may determine seed transmission of endophyte in tall fescue.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.122-122
• /
• 2017

Wheat wild relatives that have never been domesticated contained useful genetic resources such as the resistance to abiotic and biotic stresses. Leymus racemosus is one of the wild species. It can grow in a harsh environment like seaside and distribute by healthy rhizomes. Also, it has a useful genetic resource such as salt tolerance and different diseases resistance. Wheat (Triticum aestivum L. cv. Chinese Spring; CS) was crossed with L. racemosus. Wheat-L. racemosus disomic addition lines were produced. The purpose of this study is to identify protein expression in each disomic addition line compared to CS. We performed two-dimensional electrophoresis. Two-dimensional gels stained with coomassie brilliant blue (CBB), a total of 1566 differentially expressed proteins were identified by Progenesis Same Spots software from the cultivars. However, a total of 90 protein spots were identified to be either present or absent or showing significantly differential expression when the difference threshold was set to more than 1.5 fold. However, out of the 90 differentially protein spots, a total of 74 spots were sorted for mass spectrometry analysis. The identified proteins may provide important clues for better understanding the molecular changes in the chromosomes carrying Leymus racemosus.

• Journal of Plant Biotechnology
• /
• v.43 no.2
• /
• pp.189-203
• /
• 2016

Brassica oleraceae var capitata is a member of the Brassicaceae family and is widely used as an horticultural crop. In the present study, transcriptome analysis of B. oleraceae L. var capitata was done for the first time using eight-week old seedlings treated with $50{\mu}m$ MeJA, versus mock-treated samples. The complete transcripts for both samples were obtained using the GS-FLX sequencer. Overall, we obtained 275,570 and 266,457 reads from seedlings treated with or without $50{\mu}m$ MeJA, respectively. All the obtained reads were annotated using biological databases and functionally classified using gene ontology (GO), the Kyoto Encyclopedia of Genes and Genomics (KEGG). By using GO analyses, putative transcripts were examined in terms of biotic and abiotic stresses, cellular component organization, biogenesis, and secondary metabolic processes. The KEGG pathways for most of the transcripts were involved in carbohydrate metabolism, energy metabolism, and secondary metabolite synthesis. In order to double the sequenced data, we randomly chose two putative genes involved in terpene biosynthetic pathways and studied their transcript patterns under MeJA treatment. This study will provide us a platform to further characterize the genes in B. oleracea var capitata.

• The Plant Pathology Journal
• /
• v.20 no.1
• /
• pp.41-45
• /
• 2004

Plants have the ability to defend themselves against pathogens by activating a series of defense responses. SA is known to be a signal molecule in plant defense responses. Nevertheles, SA is not the only one signal mediating defense responses. In addition to SA, ethylene and jasmonic acid have also been known to mediate plant defense responses against pathogens. The activation of a series of plant defense responses is known to be through varieties of transcription factors. Specially AP2/EREBP transcription factors are involved in ethylene mediated defense signaling. In this review, recent progress on AP2/EREBP transcription factors in arabidopsis, tomato and tobacco and a few of AP2/ EREBP transcription factors in rice related to biotic stresses will be discussed.