Microalgae are a group of photosynthetic microorganisms living in the water. They are in the spotlight as biostimulators and biofertilizers in modern renewable and sustainable agriculture system, attributed to characteristics such as photosynthetic, and metabolism of various industrial wastes and to increase production when treating crops. Scenedesmus sp. CHK0059 is also one of the microalgae with these characteristics, and it has been reported to suppress various diseases in crops and promote the health of vegetables. However, the mode of action that has a positive effect on plants is not yet well understood. This study was designed to focus on the modulation in diversity change of plant microbiota community, which was the result of the preliminary study, and to determine the direct changes in microbial members that trigger the diversity change in the Arabidopsis model system. As a result, there was no change in the phenotype of Arabidopsis and the microbiota community structure in the rhizosphere during the treatment period, but two bacteria genera, Brevibacterium and Pseudomonas, dominance in the rhizosphere was positively correlated with the CHK0059 treatments. And the bacteria had a positive network correlative relationship with 24 other bacteria. Our findings suggest that the application of microalgae was correlated with several microbiota members in the rhizosphere and was expected to affect the microbiota community structure modification in long-term treatment.

본 연구는 식물검역 분야에서 주요하게 사용되고 있는 메틸브로마이드 훈증제로 인해 발생하는 약해를 저감하기 위한 물질을 모델식물인 애기장대를 이용하여 스크리닝하였다. 사전연구를 통하여 메틸브로마이드 훈증제의 식물 독성 메커니즘으로 활성산소발생와 식물 성장 호르몬인 옥신의 식물체 내 분배억제효과가 발생하는 것을 바탕으로 하여, 약해 저감물질후보군으로 활성산소를 제거하는 역할을 하는 ROS scavenger 2종 (NAC, GSH)과 옥신을 훈증제 처리 전 애기장대에 처리한 후 약해의 저감 정도를 육안평가와 더불어 관련 유전자의 발현을 확인하였다. 연구 결과 메틸브로마이드에 의해 유도된 약해는 옥신보다는 활성산소를 저감시키는 물질후보군들에서 약해 저감효과가 나타났다. 이 중 GSH을 이용하여 농도구배하여 전처리하였을 때, 5 mM GSH 전처리 후 메틸브로마이드 훈증 시 약해 저감효과가 두드러졌다. GSH 전처리 시 식물체 내에 MBF1c와 HSP70 유전자 발현이 증가하는 것을 확인하였으며, 이는 메틸브로마이드 훈증으로 유도되는 약해를 방어하는 역할을 담당하였을 것이라고 평가된다. 따라서, 식물검역 훈증제 메틸브로마이드에 의해 발생하는 약해를 저감하는 데 GSH의 사용가능성을 평가하였으며, 이를 기반으로 다양한 식물체에 적용하여 수출입 시 약해로 인한 경제적 손실을 감소시킬 수 있기를 기대한다.

Recently, RNA interference (RNAi) technology has been emerged as a potent tool for pest control strategy. Based on the previous studies on RNAi via leaf disc-mediated systemic delivery of dsRNA and in planta expression of hairpin RNA by agroinfiltration, the coatomer subunit alpha (COPA) gene has been found to be a crucial target for RNAi against Tetranychus urticae. In current study, transgenic plants of Arabidopsis thaliana expressing COPA hairpin RNA were generated by the floral dip method. Putative transgenic plants were screened by PCR and positive transformants were subjected to bioassay using age-synchronized and host-adapted T. urticae. T. urticae feeding on plants expressing dsRNA/siRNA showed more than 80% mortality as compared to the mites feeding on control plants at 6 days post-infestation. Our data shows that in planta expression of hairpin gene such as COPA may serve as an effective way for the control of this important pest in ornamental and economically important plants.

As a preceding study for investigating the influence of sound wave stimulus on Arabidopsis thaliana metabolomics, the polar secondary metabolomes of the plant were determined using high performance liquid chromatography coupled with tandem mass spectrometry. A total of 10 polar secondary metabolomes were characterized and quantified. Among them, 4 metabolomes, p-coumaroylagmatine isomer (7 and 8), p-coumaroylagmatine isomer (9 and 10) were identified in the plant for the first time. The validation was conducted in terms of linearity, recovery, precision, limit of detection (LOD) and limit of quantification (LOQ). The validated method was applied to the simultaneous quantification of the 10 polar secondary metabolomes.

We identified cdf based on screening of the Arabidopsis cDNA library for functional suppressors of the AtBI-1 (a gene described to suppress the cell death induced by Bax gene expression in yeast). The cdf was located on Chr. V and was composed of 5 exons and 4 introns. It encodes a protein of 258 amino acid residues with a molecular weight of 28.8 kDa. The protein has 3 transmembrane domains in the C-terminal region. The cdf has one homologue, named cdf2, which was found in Arabidopsis. Like cdf, cdf2 also induced growth defect in yeast. The effect of the cell growth defect factor was somewhat lower than Bax. cdf could arrest the growth of yeast. Its localization to the nucleus was essential for the suppression of yeast cell proliferation. Morphological abnormality of intracellular network, which is a hallmark of AtBI-1, was attenuated by expression of cdf.

Arabidopsis E3 SUMO ligase SIZ1 (AtSIZ1) controls vegetative growth and development including responses to nutrient deficiency and environment stresses. Here, we analyzed the effect of AtSIZ1 on the stability and amount of seed proteins. Proteomic analysis showed that the amount of three major nutrient reservoir proteins, CRUCIFERIN (CRU) 1, 2 and 3, were decreased in siz1-2 mutants. However, quantitative real-time RT-PCR showed that transcript levels of CRU1, 2 and 3 genes were rather significantly higher in siz1-2 mutants than wild-type plants. Yeast two hybrid analysis revealed that AtSIZ1 interacts with CRU1, CRU2 and CRU3, strongly suggesting that CRU1, 2 and 3 proteins are sumoylated by AtSIZ1. In addition, the analysis of amino acid composition by HPLC showed that the contents of amino acids were a bit high in siz1-2 mutants. Our data indicate that AtSIZ1 plays an important function for accumulation of seed storage proteins through its ligase activity.

Sound and communication through it have significantly contributed to study the ecology, evolution, behavior in animal. Plants may also use sound, but until now, we have been unable to effectively research what the ecological, evolutionary and molecular implications might be in plant. So, we wonder what genes are regulated under sound wave conditions. In particular, our research was centered to increase functional materials including vitamins and anthocyanin in plants. First, we investigated up- and down-regulated genes under sound wave treatments (250, 500, 800, 1000 and 1500Hz) by RNA-seq in Arabidopsis thaliana. In these results, we selected genes of over 8-fold increase and below 8-fold decrease and especially, focus on vitamin and anthocyanin-related genes in RNA-seq level. Second, we confirmed that these up- and down-regulated genes under sound wave treatments by qRT-PCR. Finally, we selected 13 interesting genes. To confirm these results, now, we are performing promoter assay by using promoter-GUS in plant and by using promoter-luciferase in protoplast. After then, we will find to interacting partners of these genes in sound wave signal. Our final goal is understand signaling network under sound wave treatment condition in plant. We hope that if we do find results that suggest that sound wave have a beneficial effect on crop yield and quality, acoustic biology can then have some viable application in agriculture. This could bring new discoveries into development of farming methods.

Cross-species translation of genomic information may play a crucial role in applying biological knowledge gained from one species to other genomes. To screen and identify a broad range of abiotic stress-responsive genes, we employed a diverse array of resources, including Arabidopsis databases (http://www.arabidopsis.org), expression profiling data and previously reported literatures. As a result, a total of 1,377 genes were identified and classified into 18 different functional criteria based on biological processes of gene ontology. The gene set was translated into M. truncatula, which is a representative model system in the Fabaceae, by identifying orthologous genes between these two genomes with a combination of tBlastx and BlastP analyses. It is shown that approximately 82% of genes were estimated to be translated between the two genomes below the E-value of 10-30. These orthologous loci were used to construct comparative maps by developing a user-friendly analysis platform, resulting in a total of 52 synteny blocks. Furthermore, to discover central genes by which control responses to the abiotic stresses, a combination of AraNet (http://www.functionanet.org) and the Cytoscape program was used for the gene network analysis. The analysis resulted in the identification of 240 potential key genes. We anticipate that these genes may impact molecular breeding programs by discovering trait-associated SNPs followed by marker development.

The transport of nascent messenger RNA from the nucleus to the cytoplasm is mediated by the THO/TREX complex and is evolutionary conserved from yeast, metazoa and humans. However, in plants, it is still yet unclear if the similar mechanism of transport exists. Here we identified and characterized a mutant gene, AtTHO2, a putative Arabidopsis thaliana THO2 component protein, homologous to yeast THO2 of the THO/TREX pathway required for mRNA transport. The mutation from this gene resulted to various developmental defects that include semi-dwarfism and abnormal floral development which further leads to sterility. Gene expression analysis revealed that AtTHO2 is expressed in all organs and pollen developmental stages. In addition, the homozygote progeny of null mutants did not persist until mature stage. These results suggest an indispensable role of AtTHO2 in the development of Arabidopsis. Differential gen expression and silencing were also observed between the null mutants and wild type depending on T-DNA insertion. Furthermore, alternative splicing which was tightly linked with the THO/TREX pathways was also defective on AtTHO2 and null mutants. A similar pattern of defect in SR34a was observed in the AtTHO2 and null mutants. In terms of microRNA biosynthesis, no significant differences were seen on the wild-type and mutant plants; however this data should be validated. Thus this work provides some evidences that a similar THO/TREX complex exist in plants and gave a foundation for further studies on the mechanism of nuclear export in plants.

To develop a strong root-specific gene expression system, six gene promoters were investigated by using transgenic Arabidopsis and a GUS:GFP reporter gene. These promoters were initially selected from Arabidopsis genes which are specifically expressed only in roots, based on the TIGR information. The GUS activity of these promoters was measured in several tissues of Arabidopsis by using both histochemical and fluorimetric GUS assays. The results showed that the activity of these promoters was strongly detected only roots. This was also confirmed by RT-PCR analysis. Therefore, these six promoters could be used for utilization of a root-specific expression of target genes.

This study was performed to examine the accumulated concentrations (conc.) of cadmium (Cd) in the organs of Arabidopsis thaliana grown in the soil with different conc. of Cd. The official standard conc. of Cd of pollutant exhaust notified by the Korean ministry of environment (0.1 mg/L) and ten times higher (1 mg/L) and fifty times higher (5 mg/L) conc. and no Cd in the soil as control were used for this investigation. The results showed that accumulated conc. of Cd in the stems of plant grown in the soil with different conc. (0.1, 1 and 5 mg/L) were increased 9%, 24% and 286% respectively, compared with normal plant stem. The accumulated conc. of Cd in the leafs of plant grown in the soil with official standard conc. and conc. ten times higher and conc. fifty times higher were increased 3%, 22% and 453%, respectively, compared with normal plant leaf. The accumulated conc. of Cd in the root of plant grown in the soil with 0.1 and 1 mg/L conc. of Cd were increased 6%, 19%, respectively, compared with normal plant root. However, it was observed about 84% of increased accumulation of the Cd in the root of plant, when highest (5 mg/L) conc. was used. The accumulated conc. of Cd in the different organs of Arabidopsis thaliana were increased according to increase of Cd conc. in the soil. When official standard conc. and ten times higher conc. of Cd were used, the accumulated conc. of Cd increased average 6%, 21%, respectively, compared with normal plant organ, and the accumulated conc. of Cd between leaf, stem and root were not significant. However, the accumulated conc. of Cd in the plant organs grown in the conc. fifty times higher were increased about 285%, compared with normal plant. In addition, the accumulated conc. of Cd in different organs of Arabidopsis thaliana exhibited wide differences between organs, that is, stem was increased 118% than root, leaf was increased 256%, 64% than root and stem, respectively. These results show that accumulated conc. of Cd in Arabidopsis thaliana with highest (5 mg/L) conc. of Cd in soil, were much higher in the leaf than the stem or root in proportion to the conc. of Cd contaminated within the soil.

Organ abscission is a programmed cell separation process that results in the detachment of an entire organ from a plant. Our goal is to understand the signaling pathway that regulates this physiological process. The receptor-like protein kinase, HAESA (HAE), and its paralog, HAESA-like 2 (HSL2), are both expressed in the floral abscission zones in Arabidopsis thaliana. Loss-of-function analyses of either gene do not show any phenotypical change, but the hae hsl2 double mutant shows an abscission-defect phenotype. Examination of the abscission zone by light and scanning electron microscopy showed that the abscission zone in the hae hsl2 appears structurally normal. The force required to remove the petals in wild type and hae hsl2 flowers was measured using a petal breakstrength meter. The force required to remove petals from the hae hsl2flowers at all stages of development was similar to that of wild type flowers that have not yet begun to abscise their petals. Taken together, these data support the role of HAE and HSL2 in the activation of cell separation, rather than differentiation of the abscission zone. Ethylene is also known to promote abscission; therefore we tested the ethylene-induced triple response and the effect of exogenous treatment on floral organ in the hae hsl2, revealing that HAE and HSL2 act independently of ethylene. This implies that the HAE is critical for floral abscission in concert with the action of HSL2.