• The Plant Pathology Journal
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• 제30권3호
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• pp.269-278
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• 2014

Remorins, a family of plant-specific proteins containing a variable N-terminal region and conserved C-terminal domain, play a role in various biotic and abiotic stresses, including host-microbe interactions. However, their functions remain to be completely elucidated, especially for the Arabidopsis thaliana remorin group 4 (AtREM4). To elucidate the role of remorins in Arabidopsis, we first showed that AtREM4s have typical molecular characteristics of the remorins, such as induction by various types of biotic and abiotic stresses, localization in plasma membrane and homo- and hetero-oligomeric interaction. Next, we showed that their loss-of-function mutants displayed reduced susceptibility to geminiviruses, Beet Curly Top Virus and Beet Severe Curly Top Virus, while overexpressors enhanced susceptibility. Moreover, we found that they interacted with SnRK1, which phosphorylated AtREM4.1, and were degraded by the 26S proteasome pathway. These results suggest that AtREM4s may be involved in the SnRK1-mediated signaling pathway and play a role as positive regulators of the cell cycle during geminivirus infection.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2007년도 춘계학술발표회
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• pp.245-246
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• 2007

• 식물조직배양학회지
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• 제25권3호
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• pp.153-158
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• 1998

Arabidopsis thaliana에 beet curly top virus (BCTV)를 인공접종하여 외부병징 및 조직내부구조 변화를 광학현미경으로 검경하였다. BCTV-Logan에 접종된Arbidopsis thaliana ecotype Sei-O 줄기에서 약 2주 후 이상비대현상이 관찰되었고, 약 4주 후에는 캘러스조직이 형성되었다. 감염된 각 시기별로 증상부위의 Sei-O 줄기를 횡단절단하여 관찰한 결과 다음과 같은 순서, (1) 사부조직의 이상비대, (2) 이상비대된 사부의 괴사, (3) 괴사조직의 lacuna 형성, (4) lacuna형성된 사부 주위의 피층과 표피세포 신장 및 확대, (5) 신장된 피층 및 표피세포에서의 세포분열 유도, (6) 캘러스 조직의 유도 순으로 내부구조 변화가 관찰되었다. BCTV에 감염된 Arabidopsis에서의 캘러스 형성은 바이러스의 감염결과로 유도되었으며, azure-A염색법에 의해 바이러스 inclusion body는 사부조직과 캘러스에서도 존재함이 관찰되었다. 본 연구 결과 BCTV에 감염된 Arabidopsis에서 관찰된 캘러스 형성의 원인은 감염된 숙주식물의 사부조직의 괴사에 따른 lacuna 주위 피층세포의 세포분열에 기인한 것으로 사료된다.

• Journal of Plant Biology
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• 제39권4호
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• pp.249-256
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• 1996

Beet curly top virus is the DNA virus that is providing useful for basic studies of the infection of Arabidopsis thaliana with viral host and provides a system for studying both resistance and the molecular basis of symptom development. An importnat aspect of symptom development observed in BCTV-infected A. thaliana (ecotype Sei-O) was the induction of cell division on phloem and surrounding cortex cells. Analysis of the expression of GUS reporter gene activity in transgenic plants containing constructs with promoter of the auxin-inducible saur gene showed that saur promoter activity was induced concomitantly in symptomatic tissues at the inflorescence shoot tips of the transgenic lines. The auxin sensitivity tests showed that hypersusceptible ecotype, Sei-O produced more amounts of callus than susceptible ecotype, Col-O. These studies indicated that changes in auxin concentration were involved in the induction of cell division in BCTV-infected plants and clearly demonstrated that there was a strong correlation between auxin-induced gene expression and the activation of cell division.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.218-218
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• 2005

• The Plant Pathology Journal
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• 제21권4호
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• pp.355-360
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• 2005

Sulfur, an important component of plants, is regulated by a variety of stresses in sulfate assimilation and metabolism. Increase has been observed in the expression of O-acetylserine(thiol)lyase (OASTL) through two-dimensional electrophoresis with the shoot tips of Arabidopsis infected by beet severe curly top geminivirus (BSCTV). With the three- to six-fold increases in the transcript expression of OASTL, serine acetyltransferase (SAT) and $\gamma$-glutmylcysteine synthetase (GSH) were induced over the mock-inoculated organization in each organization through real-time RT-PCR analysis. The expression of those genes might affect the accumulation of anthocyanin in symptomatic tissues and the induction of abnormal callus-like structures formed by additional cell divisions as typical disease symptoms of BSCTV-infected Arabidopsis. This is the first report to describe the collaborative induction of OASTL, SAT, and GSH in virus-infected plants. The changed expressions of OASTL, SAT, and GSH in Arabidopsis infected with BSCTV raises new aspects regarding the biological function of symptomatic tissues related to sulfate metabolism.

• Journal of Plant Biotechnology
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• 제30권2호
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• pp.129-133
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• 2003

The factors for symptom development caused by Beat curly top virus(BCTV) have been analyzed by using a molecular genetic approach based on expressing BCTV encoded proteins in transgenic plants. BCTV open reading frame (ORF) L4 expression in transgenic Arabidopsis resulted in abnormal plant development and the production of callus inflorescence stems and bumpy trichomes, confiming that this gene alone is a primary symptom determinant. The L4 gene expression by northern hybridization in transgenic plants and a range of phenotypes were analyzed.

• Molecules and Cells
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• 제23권1호
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• pp.80-87
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• 2007

Beet curly top virus (BCTV) and Beet severe curly top virus (BSCTV), members of curtoviruses, encode seven open reading frames (ORFs) within a ~3 kb genome. One of these viral ORFs, C1, is known to play an important role in the early stage of viral infection in plants during initiation of viral DNA replication. We used promoter:: reporter (${\beta}$-glucuronidase) gene fusions in transgenic Arabidopsis to identify the putative promoter region of BCTV ORF C1. Unlike other geminiviruses, the intergenic region of BCTV was not sufficient to promote C1 expression in transgenic plants. When sequences extending into the coding region of C1 were tested, strong expression of the reporter protein was observed in vascular tissues of transgenic plants. This expression was not dependent on the presence of the intergenic regions or proximal 5' portions of the C1 coding region. Transgenic plants expressing a reporter gene under control of the putative complete C1 promoter were inoculated with virus to determine if any viral transcript affected C1 expression. Virus inoculated plants did not show any altered pattern or change in of reporter gene expression level. These results suggest that (1) important transcriptional activator elements for C1 expression reside in the 3' portion of C1 coding area itself, (2) C1 protein does not auto-regulate its own expression and (3) C1 expression of two curtoviruses is controlled differently compared to other geminiviruses.

• 한국식물병리학회지
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• 제14권5호
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• pp.507-512
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• 1998

Molecular analysis has been done for characterization of the interactions between three beet curly top virus (BCTV) strains and two Arabidopsis ecotypes in terms of virus inducible disease symptoms and infectivities. The total DNA was isolated from three tissues (shoot tips, infection origins and roots) of virus infected plants and this DNA was analyzed by quantitatively and qualitatively to elucidate virus movement and symptom development. CTV-Worland infected Col-O and Sei-O showed only symptom shown in hypersusceptible ecotype Sei-O by BCTV-worland was shoot tip stunting. Kinetics of virus DNA accumulation of three different viruses indicated that roots contained more virus DNA than shoot tips or infection origins, and that disease symptom severity was strongly correlated with virus DNA accumulation. These results suggest that the mild and Worland-specific symptoms shown in Sei-O by BCTV-worland are caused by the interactions of host factors provided by hypersusceptible ecotype and viral factors of mild strain.

• Molecules and Cells
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• 제26권2호
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• pp.131-139
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• 2008

Expression of the seven open reading frames (ORFs) of single-stranded DNA Curtoviruses such as Beet curly top virus (BCTV) and Beet severe curly top virus (BSCTV) is driven by a bi-directional promoter. To investigate this bidirectional promoter activity with respect to viral late gene expression, transgenic Arabidopsis plants expressing a GUS reporter gene under the control of either the BCTV or BSCTV bi-directional promoter were constructed. Transgenic plants harboring constructs showed higher expression levels when the promoter of the less virulent BCTV was used than when the promoter of the more virulent BSCTV was used. In transgenic seedlings, the reporter gene constructs were expressed primarily in actively dividing tissues such as root tips and apical meristems. As the transgenic plants matured, reporter gene expression diminished but viral infection of mature transgenic plants restored reporter gene expression, particularly in transgenic plants containing BCTV virion-sense gene promoter constructs. A 30 base pair conserved late element (CLE) motif was identified that was present three times in tandem in the BCTV promoter and once in that of BSCTV. Progressive deletion of these repeats from the BCTV promoter resulted in decreased reporter gene expression, but BSCTV promoters in which one or two extra copies of this motif were inserted did not exhibit increased late gene promoter activity. These results demonstrate that Curtovirus late gene expression by virion-sense promoters depends on the developmental stage of the host plant as well as on the number of CLE motifs present in the promoter.