Trait Development with CRISPR/Cas9 Technology in Non-GMO way

Sunghwa Choe 한국원예학회 2016 한국원예학회 학술발표요지 Vol.2016 No.10

Brassinosteroid biosynthesis and inactivation

Blackwell Publishing Ltd 2006 Physiologia plantarum Vol.126 No.4

<P>The term brassinosteroids (BRs) refers to the growth-promoting plant steroidal hormones. Various developmental programs including but not limited to cell elongation, stress tolerance, and skoto-/photo-morphogenesis are controlled by subnanomolar concentrations of BRs. Accordingly, BR mutants that are defective in BR biosynthetic or signaling pathways usually display dwarfism. Characterization of numerous BR dwarf mutants isolated from <I>Arabidopsis</I>, pea, tomato, and rice greatly contributed to our understanding of BR biology. Recently, an enzyme that mediates the final step in the BR biosynthetic pathways has been characterized by two different groups. The brassinolide synthases (Cytochrome P450s 85A2 and 85A3) are multifunctional enzymes that catalyze the last three consecutive steps in BR biosynthetic pathways, namely, C-6 hydroxylation, dehydrogenation, and Baeyer-Villiger type oxidation. In addition, many of the previously unknown steps have been genetically characterized. This review aims to summarize the knowledge that has been developed during the last 2–3 years in this field of BR biosynthesis and inactivation research.</P>

The Regulation of Brassinosteroid Biosynthesis in Arabidopsis

Chung, Yuhee,Choe, Sunghwa Taylor Francis 2013 Critical reviews in plant sciences Vol.32 No.6

Constitutive activation of brassinosteroid signaling in the Arabidopsis elongated-D/bak1 mutant

Chung, Yuhee,Choe, Vitnary,Fujioka, Shozo,Takatsuto, Suguru,Han, Muho,Jeon, Jong-Seong,Park, Youn-Il,Lee, Kyun Oh,Choe, Sunghwa Springer-Verlag 2012 Plant molecular biology Vol.80 No.4

Simultaneous suppression of three genes related to brassinosteroid (BR) biosynthesis altered campesterol and BR contents, and led to a dwarf phenotype in Arabidopsis thaliana

Chung, Ho Yong,Fujioka, Shozo,Choe, Sunghwa,Lee, Soyoun,Lee, Youn Hyung,Baek, Nam In,Chung, In Sik Springer-Verlag 2010 Plant cell reports Vol.29 No.4

Novel Simple Sequence Length Polymorphic (SSLP) Markers for Positional Cloning in Arabidopsis thaliana

Kwon, Mi,Lee, Hyun Kyung,Choe, Sunghwa 한국유전학회 2005 Genes & Genomics Vol.27 No.1

T-DNA-based tagging technology facilitated isolation of biologically important genes from the Arabidopsis genome. However, the technology frequently results in untagged mutants that are free of T-DNA but contain mutations due to deletions of varying size of genomic DNA. To clone a gene from the T-DNA or ethylmethanesulfonate (EMS)-mutagenized point mutant populations, map-based cloning method should be exercised. Arabidopsis genome database contains a great number of genetic markers, but easy-to-use PCR-based markers are only scarcely distributed over the genome especially for other ecotypes than Columbia and Landsberg. For this reason, we have developed 23 novel simple sequence length polymorphism (SSLP) markers in the cloning process of an EMS-induced point mutation of the gulliver2 gene. We examined polymorphisms of these novel markers from 4 different ecotypes, Columbia, Wassilevskija-2, Landsberg erecta, and Enkheim-2. These markers will be useful for genotyping and map-based cloning of a gene in Arabidopsis.

Antagonistic Regulation of Arabidopsis Growth by Brassinosteroids and Abiotic Stresses

Chung, Yuhee,Kwon, Soon Il,Choe, Sunghwa Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.11

To withstand ever-changing environmental stresses, plants are equipped with phytohormone-mediated stress resistance mechanisms. Salt stress triggers abscisic acid (ABA) signaling, which enhances stress tolerance at the expense of growth. ABA is thought to inhibit the action of growth-promoting hormones, including brassinosteroids (BRs). However, the regulatory mechanisms that coordinate ABA and BR activity remain to be discovered. We noticed that ABA-treated seedlings exhibited small, round leaves and short roots, a phenotype that is characteristic of the BR signaling mutant, brassinosteroid insensitive1-9 (bri1-9). To identify genes that are antagonistically regulated by ABA and BRs, we examined published Arabidopsis microarray data sets. Of the list of genes identified, those upregulated by ABA but downregulated by BRs were enriched with a BRRE motif in their promoter sequences. After validating the microarray data using quantitative RT-PCR, we focused on RD26, which is induced by salt stress. Histochemical analysis of transgenic Arabidopsis plants expressing RD26pro:GUS revealed that the induction of GUS expression after NaCl treatment was suppressed by co-treatment with BRs, but enhanced by co-treatment with propiconazole, a BR biosynthetic inhibitor. Similarly, treatment with bikinin, an inhibitor of BIN2 kinase, not only inhibited RD26 expression, but also reduced the survival rate of the plant following exposure to salt stress. Our results suggest that ABA and BRs act antagonistically on their target genes at or after the BIN2 step in BR signaling pathways, and suggest a mechanism by which plants fine-tune their growth, particularly when stress responses and growth compete for resources.

Isolation of rice T-DNA tagged mutants being resistant to brassinosteroid (BR) biosynthetic inhibitor Propiconazole (Pcz)

Claudia Corvalán,Soon Il Kwon,Haerim Kim,Doyeon Kim,Jewook Woo,Sunghwa Choe 한국육종학회 2015 한국육종학회 심포지엄 Vol.2015 No.07

Hormones play a crucial role in controlling physiological processes, and thus plants grow and develop in response to environmental cues through the interlocked actions of the hormones. Brassinosteroids (BRs) were found as growth-promoting steroid hormones. Rice, as a monocotyledonous model plants and the major staple crop, has been used to study BR action mechanisms. However, many components of BR pathways and the mechanisms of their molecular interactions have yet to be fully understood. Because the use of the BR biosynthetic inhibitor, Brassinazole (Brz), allowed us to identify important components of BR signaling such as the transcription factor BZR1, we decided to employ a similar strategy to identify novel signaling factors using propiconazole (Pcz), a new potent BR inhibitor. We screened a rice T-DNA mutant population which belongs to Dongjin variety and were developed by the Gene An’s group using pGA2715 T-DNA vector. Using Pcz treatments we searched for resistant plants, which were reflected on their lengths of roots and/or leaves. We isolated a total of 17 mutant lines, which are being analyzed phenotypically and at molecular level. So far, we have been able to found various lines presenting high or low yield compared to their wild type counterparts. We have found differences in panicle organization of these mutants. Our current experiments include the confirmation of Pcz resistance of these lines and molecular studies involving BR marker genes to understand the relation among yield and BR action in rice.

DNA-free Genome Editing in Plants

Soon-Il Kwon,Je Wook Woo,Jungeun Kim,Jin-Soo Kim,Sunghwa Choe 한국육종학회 2015 한국육종학회 심포지엄 Vol.2015 No.07

CRISPR/Cas9-based genome editing technology fast replaces the previous methods that require protein engineering such as Zinc Finger Nucleases (ZFNs) and TALE nucleases (TALENs). Conventional genome editing of plant cells using CRISPR/Cas9 technology largely depends on Agrobacterium-mediated transformation of the plant cells and subsequent regeneration of whole plants from the edited cells. During this process, unwanted foreign DNAs including the antibiotics gene and fragments of the T-DNA can be introduced into plant genome. Insertion of these unwanted DNA causes lots of regulatory restrictions when commercializing the LMO products. To step aside these issues, we designed DNA-free ribonucleoprotein-based method and regenerated whole plants from the successfully engineered cells. We will share our discovery on the successful implement of this technology in lettuce protoplasts.

A Study on the Analysis of Optimal Growth Conditions for Arabidopsis for HA Protein Expression Produced

( Hyunhwan Kim ),( Jeongwook Heo ),( Gongin Lee ),( Jaesu Lee ),( Youngsin Hong ),( Sunghwa Choe ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

For years, efforts have been made to increase the added value of crops, to produce high-yield crops containing large amounts of functional materials, or to develop new products to secure the economical efficiency of artificial light plant factories. Arabidopsis is a crop that produces high-value recombinant proteins. It is known that various genetic manipulations of the crop are possible and medical proteins can be extracted from it. In this study, varieties, temperature, type of lamp, and photoperiodic response were investigated for the plant growth of the varieties Ariabiopsis as a precondition that the protein content of Arabidopsis was correlated with leaf weight. For the test, nine kinds of Arabidopsis seeds (JL00458.1, JL00510.1, JL00513.1, JL00528.1, JL00610.1, and COL) were sown in the smart greenhouse research center for the plant factory in Jeonju. Four weeks later, four chambers of 55% relative humidity and temperature (20, 24° C) were made. The cultivation method is nutrient flow technique (NFT). The light in the chamber consisted of fluorescent lamps and LEDs. The light intensity was 150 μmol m-2 · s-1, and it was divided into 12 hours and 16 hours. Growth survey was conducted once a week from December 2016 to February 2017. In fluorescent lamp, the plant length was increased. After 3 weeks had elapsed under the conditions of irradiation at 20℃ and 12 hours, the average length was more than 6 cm. At 5 weeks, some varieties (JL00458.1, JL00528.1, and JL00610.1) exceeded 9 cm and were excellent. Comparing at 12 and 16 hours at 24℃, it was confirmed that the growth rate was fastest in 2nd ~ 4th weeks in some varieties. In LED lamp, the plant length was also increased. After 4 weeks had elapsed under conditions of irradiation at 20℃ and both 12 and 16 hours, the average length 6 cm mostly. At 7 weeks, COL did not exceed 9 cm under the conditions of irradiation at 20℃ and 12 hours, and three varieties did not exceed 9 cm under the conditions of irradiation at 20℃ and 16 hours. Therefore, it was found that 12 hours was better at 20℃. As a result, fluorescent lamp, 20 ° C, and 12 hours condition and varieties (JL00458.1 and JL00510.1) are considered to be suitable.