Researches:
Article title: The overexpression of OsNAC9 alters the root architecture of rice plants enhancing drought resistance and grain yield under field conditions
Authors: Mark C.F.R. Redillas, Jin S.Jeong, Youn S. Kim, Harin Jung, Seung W. Bang,Yang D.Choi, Sun-Hwa Ha, Christophe Reuzeau and Ju-Kon Kim
Publication title: Plant Biotechnology Journal 10(7):792-805, May 2012
Abstract:
Drought conditions limit agricultural production by preventing crops from reaching their genetically predetermined maximum yields. Here, we present the results of field evaluations of rice overexpressing OsNAC9, a member of the rice NAC domain family. Root-specific (RCc3) and constitutive (GOS2) promoters were used to overexpress OsNAC9 and produced the transgenic RCc3:OsNAC9 and GOS2:OsNAC9 plants. Field evaluations over two cultivating seasons showed that grain yields of the RCc3:OsNAC9 and the GOS2:OsNAC9 plants were increased by 13%-18% and 13%-32% under normal conditions, respectively. Under drought conditions, RCc3:OsNAC9 plants showed an increased grain yield of 28%-72%, whilst the GOS2:OsNAC9 plants remained unchanged. Both transgenic lines exhibited altered root architecture involving an enlarged stele and aerenchyma. The aerenchyma of RCc3:OsNAC9 roots was enlarged to a greater extent than those of GOS2:OsNAC9 and non-transgenic (NT) roots, suggesting the importance of this phenotype for enhanced drought resistance. Microarray experiments identified 40 up-regulated genes by more than threefold (P < 0.01) in the roots of both transgenic lines. These included 9-cis-epoxycarotenoid dioxygenase, an ABA biosynthesis gene, calcium-transporting ATPase, a component of the Ca(2+) signalling pathway involved in cortical cell death and aerenchyma formation, cinnamoyl CoA reductase 1, a gene involved in lignin biosynthesis, and wall-associated kinases¸ genes involved in cell elongation and morphogenesis. Interestingly, O-methyltransferase, a gene necessary for barrier formation, was specifically up-regulated only in the RCc3:OsNAC9 roots. Such up-regulated genes that are commonly and specifically up-regulated in OsNAC9 transgenic roots may account for the altered root architecture conferring increased drought resistance phenotype.
Full text link https://tinyurl.com/3ttuash9
Article title: Accumulation of trehalose increases soluble sugar contents in rice plants conferring tolerance to drought and salt stress
Authors: Mark C. F. R. Redillas, Su-Hyun Park, Jang Wook Lee, Youn Shic Kim, Jin Seo Jeong, Harin Jung, Seung Woon Bang, Tae-Ryong Hahn, Ju-Kon Kim
Publication title: Plant Biotechnology Reports 6(1), 2011
Abstract:
Trehalose is a nonreducing sugar composed of two glucose units linked in an α,α-1,1-glycosidic linkage. Present in a wide variety of organisms, this sugar may serve as a source of energy and carbon and as a protective molecule against abiotic stresses. In this study, trehalose-producing transgenic rice plants (Oryza sativa) expressing a bifunctional fusion enzyme TPSP (Ubi1:TPSP) were utilized to dissect the enigmatic role of trehalose in conferring stress tolerance to plants. Grown under normal conditions, the Ubi1:TPSP plants produced high amounts of soluble sugars (glucose, fructose and sucrose), ranging from 1.5- to 3.5-fold over NT controls. In the time course of drought treatment, the transcripts for the drought degradable-marker genes (RbcS, FBPase, and PBZ1) persisted for two more days in Ubi1:TPSP plants before being completely degraded relative to those in NT plants, confirming the tolerance of the transgenic plants to drought. This was further supported by a delayed increase in transcript levels of the stress-inducible genes SalT, Dip1, and Wsi18 during drought stress. Similarly, Ubi1:TPSP plants showed tolerance to salt levels of up to 150 mM NaCl, as evidenced by the seedling growth and the delayed decay in RbcS and delayed increase in SalT transcript levels. The growth of NT plants was found to be slightly affected by exogenous trehalose feeding, whereas Ubi:TPSP plants remained resistant, validating the protective role of internally produced trehalose. These results suggest that the elevated production of trehalose in rice, through TPSP overexpression, increases the soluble sugar contents and enhances tolerance to both drought and salt stress.
Full text link https://tinyurl.com/54ajhwm3
Article title: JIP Analysis on Rice (Oryza sativa cv Nipponbare) Grown under Limited Nitrogen Conditions
Authors: Mark Christian Felipe Reveche Redillas, Jin Seo Jeong, Reto Jörg Strasser, Youn Shic Kim, and Ju-Kon Kim
Publication title: Journal of the Korean Society for Applied Biological Chemistry 54(5), 2011
Abstract:
Nitrogen deficiency significantly reduces the CO2 assimilation capacity of plants and the quantum yield of photosynthesis. Here, we employed the JIP test to determine the effects of nitrogendeficiency on the plant’s photosysnthetic ability on the basis of chlorophyll fluorescence. Nitrogendeficient and nitrogen-replete rice plants were analyzed for the fluorescence transients of the plant leaves in comparison with the nitrogen-sufficient controls. Results showed that 7 day-replete plants behaved normally while 5, 3, and 1 day-replete plants were significantly affected from nitrogen starvation. More specifically, nitrogen starvation of plants resulted in an inactivation of photosystem II (PS II) reaction centers and a decline in electron transport beyond the reduced plastoquinone (QAA −), and a decrease in both the pool size and the reduction of end electron acceptors at the PS I. The affected plants were fully recovered from the deficiency after 7 days of nitrogen repletion, as evidenced by the similar level of fluorescence transients to the positive controls. Thus, our results demonstrated that the movement of electron carriers leading to the reduction of end electron acceptors was affected by nitrogen limitation leading to a more pronounced decrease in the reduction of end electron acceptors. Together with the fact that nitrogen-deficiency limits the CO2 assimilation of plants, this study indicates that nitrogen metabolism is tightly coupled with photosynthetic ability.
Full text link https://tinyurl.com/3tkdb3vj
Article title: The use of JIP test to evaluate drought-tolerance of transgenic rice overexpressing OsNAC10
Authors: Mark C. F. R. Redillas, Reto J. Strasser, Jin Seo Jeong, Youn Shic Kim, Ju-Kon Kim
Publication title: Plant Biotechnology Reports 5(2):169-175, 2011
Abstract:
In this study, the JIP test was exploited to assess drought-tolerance of transgenic rice overexpressing OsNAC10. Two types of promoters, RCc3 (root-specific) and GOS2 (constitutive), were used to drive the transcription factor OsNAC10, a gene involved in diverse functions including stress responses. Three-month-old plants were exposed to drought for 1week and their fluorescence kinetics was evaluated. Our results showed that drought-treated non-transgenic plants (NT) have higher fluorescence intensity at the J phase (2ms) compared to transgenic plants, indicating a decline in electron transport beyond the reduced plastoquinone (QA −). As manifested by negative L bands, transgenic plants also showed higher energetic connectivity and stability over NT plants under drought conditions. Also, the pool size of the end electron acceptor at the photosystem I was reduced more in NT than in transgenic plants under drought conditions. Furthermore, the transgenic plants had higher PItotal, a combined parameter that reflects all the driving forces considered in JIP test, than NT plants under drought conditions. In particular, the PItotal of the RCc3:OsNAC10 plants was higher than that of NT plants, which was in good agreement with their differences in grain yield. Thus, the JIP test proved to be practical for evaluating drought-tolerance of transgenic plants. KeywordsChlorophyll a fluorescence–JIP test–Transgenic rice–Drought stress– OsNAC10
Full text link https://tinyurl.com/yckktj4d
Article title: Allantoin accumulation through overexpression of ureide permease1 improves rice growth under limited nitrogen conditions
Authors: Mark Christian Felipe R. Redillas, Seung Woon Bang, Dong-Keun Lee, Youn Shic Kim, Harin Jung, Pil Joong Chung, Joo-Won Suh, Ju-Kon Kim
Publication title: Plant Biotechnology Journal 17(7):1289-1301, 2019
Abstract:
In legumes, nitrogen (N) can be stored as ureide allantoin and transported by ureide permease (UPS) from nodules to leaves where it is catabolized to release ammonium and assimilation to amino acids. In non‐leguminous plants especially rice, information on its roles in N metabolism is scarce. Here, we show that OsUPS1 is localized in plasma membranes and are highly expressed in vascular tissues of rice. We further evaluated an activation tagging rice overexpressing OsUPS1 (OsUPS1OX) under several N regimes. Under normal field conditions, panicles from OsUPS1OX plants (14 days after flowering (DAF)) showed significant allantoin accumulation. Under hydroponic system at the vegetative stage, plants were exposed to N‐starvation and measured the ammonium in roots after resupplying with ammonium sulfate. OsUPS1OX plants displayed higher ammonium uptake in roots compared to wild type (WT). When grown under low‐N soil supplemented with different N concentrations, OsUPS1OX exhibited better growth at 50% N showing higher chlorophyll, tiller number and at least 20% increase in shoot and root biomass relative to WT. To further confirm the effects of regulating the expression of OsUPS1, we evaluated whole‐body‐overexpressing plants driven by the GOS2 promoter (OsUPS1GOS²) as well as silencing plants (OsUPS1RNAⁱ). We found significant accumulation of allantoin in leaves, stems and roots of OsUPS1GOS² while in OsUPS1RNAⁱ allantoin was significantly accumulated in roots. We propose that OsUPS1 is responsible for allantoin partitioning in rice and its overexpression can support plant growth through accumulation of allantoin in sink tissues which can be utilized when N is limiting.
Full text link https://tinyurl.com/462ypzx7
Article title: A nitrogen molecular sensing system, comprised of the ALLANTOINASE and UREIDE PERMEASE 1 genes, can be used to monitor N status in rice
Authors: Dong-Keun Lee, Mark C F R Redillas, Harin Jung, Seowon Choi, Youn Shic Kim, Ju-Kon Kim
Publication title: Frontiers in plant science 9:444, 2018
Abstract:
Nitrogen (N) is an essential nutrient for plant growth and development, but its concentration in the soil is often insufficient for optimal crop production. Consequently, improving N utilization in crops is considered as a major target in agricultural biotechnology. However, much remains to be learnt about crop N metabolism for application. In this study, we have developed a molecular sensor system to monitor the N status in rice (Oryza sativa). We first examined the role of the ureide, allantoin, which is catabolized into allantoin-derived metabolites and used as an N source under low N conditions. The expression levels of two genes involved in ureide metabolism, ALLANTOINASE (OsALN) and UREIDE PERMEASE 1 (OsUPS1), were highly responsive to the N status. OsALN was rapidly up-regulated under low N conditions, whereas OsUPS1 was up-regulated under high N conditions. Taking advantage of the responses of these two genes to N status, we generated transgenic rice plants harboring the molecular N sensors, proALN::ALN-LUC2 and proUPS1::UPS1-LUC2, comprising the gene promoters driving expression of the luciferase reporter. We observed that expression of the transgenes mimicked transcriptional regulation of the endogenous OsALN and OsUPS1 genes in response to exogenous N status. Importantly, the molecular N sensors showed similar levels of specificity to nitrate and ammonium, from which we infer their sensing abilities. Transgenic rice plants expressing the proUPS1::UPS1-LUC2 sensor showed strong luminescence under high exogenous N conditions (>1 mM), whereas transgenic plants expressing the proALN::ALN-LUC2 sensor showed strong luminescence under low exogenous N conditions (<0.1 mM). High exogenous N (>1 mM) substantially increased internal ammonium and nitrate levels, whereas low exogenous N (<0.1 mM) had no effect on internal ammonium and nitrate levels, indicating the luminescence signals of molecular sensors reflect internal N status in rice. Thus, proALN::ALN-LUC2 and proUPS1::UPS1-LUC2 represent N molecular sensors that operate over a physiological and developmental range in rice.
Full text link https://tinyurl.com/538vpdkn
Article title: Overexpression of OsERF48 causes regulation of OsCML16 , a calmodulin-like protein gene that enhances root growth and drought tolerance
Authors: Harin Jung, Pil Joong Chung, Su-Hyun Park, Mark Christian Felipe Reveche Redillas, Youn Shic Kim, Joo-Won Suh, Ju-Kon Kim
Publication title: Plant Biotechnology Journal 15(10):1295-1308, 2017
Abstract:
The AP2/ERF family is a plant-specific transcription factor family whose members have been associated with various developmental processes and stress tolerance. Here, we functionally characterized the drought-inducible OsERF48, a group Ib member of the rice ERF family with four conserved motifs, CMI-1, -2, -3 and -4. A transactivation assay in yeast revealed that the C-terminal CMI-1 motif was essential for OsERF48 transcriptional activity. When OsERF48 was overexpressed in an either a root-specific (ROXOsERF48 ) or whole-body (OXOsERF48 ) manner, transgenic plants showed a longer and denser root phenotype compared to the nontransgenic (NT) controls. When plants were grown on a 40% polyethylene glycol-infused medium under in vitro drought conditions, ROXOsERF48 plants showed a more vigorous root growth than OXOsERF48 and NT plants. In addition, the ROXOsERF48 plants exhibited higher grain yield than OXOsERF48 and NT plants under field-drought conditions. We constructed a putative OsERF48 regulatory network by cross-referencing ROXOsERF48 root-specific RNA-seq data with a co-expression network database, from which we inferred the involvement of 20 drought-related genes in OsERF48-mediated responses. These included genes annotated as being involved in stress signalling, carbohydrate metabolism, cell-wall proteins and drought responses. They included, OsCML16, a key gene in calcium signalling during abiotic stress, which was shown to be a direct target of OsERF48 by chromatin immunoprecipitation-qPCR analysis and a transient protoplast expression assay. Our results demonstrated that OsERF48 regulates OsCML16, a calmodulin-like protein gene that enhances root growth and drought tolerance.
Full text link https://tinyurl.com/y98yna36
Article title: OsNAC5 overexpression enlarges root diameter in rice pants leading to enhanced drought tolerance and increased grain yield in the field
Authors: Jin Seo Jeong, Youn Shic Kim, Mark C. F. R. Redillas, Geupil Jang, Harin Jung, Seung Woon Bang, Yang Do Choi, Sun-Hwa Ha, Christophe Reuzeau, Ju-Kon Kim
Publication title: Plant Biotechnology Journal 11(1):101-114, 2013
Abstract:
Drought conditions are among the most serious challenges to crop production worldwide. Here, we report the results of field evaluations of transgenic rice plants overexpressing OsNAC5, under the control of either the root-specific (RCc3) or constitutive (GOS2) promoters. Field evaluations over three growing seasons revealed that the grain yield of the RCc3:OsNAC5 and GOS2:OsNAC5 plants were increased by 9%-23% and 9%-26% under normal conditions, respectively. Under drought conditions, however, RCc3:OsNAC5 plants showed a significantly higher grain yield of 22%-63%, whilst the GOS2:OsNAC5 plants showed a reduced or similar yield to the nontransgenic (NT) controls. Both the RCc3:OsNAC5 and GOS2:OsNAC5 plants were found to have larger roots due to an enlarged stele and aerenchyma at flowering stage. Cell numbers per cortex layer and stele of developing roots were higher in both transgenic plants than NT controls, contributing to the increase in root diameter. The root diameter was enlarged to a greater extent in the RCc3:OsNAC5, suggesting the importance of this phenotype for enhanced drought tolerance. Microarray experiments identified 25 up-regulated genes by more than three-fold (P < 0.01) in the roots of both transgenic lines. Also identified were 19 and 18 up-regulated genes that are specific to the RCc3:OsNAC5 and GOS2:OsNAC5 roots, respectively. Of the genes specifically up-regulated in the RCc3:OsNAC5 roots, GLP, PDX, MERI5 and O-methyltransferase were implicated in root growth and development. Our present findings demonstrate that the root-specific overexpression of OsNAC5 enlarges roots significantly and thereby enhances drought tolerance and grain yield under field conditions.
Full text link https://tinyurl.com/4z73w489
Article title: Characterization of the root-predominant gene promoter HPX1 in transgenic rice plants
Authors: Su-Hyun Park, Jin Seo Jeong, Eun Hyang Han, Mark C. F. R. Redillas, Seung Woon Bang, Harin Jung, Youn Shic Kim & Ju-Kon Kim
Publication title: Plant Biotechnology Reports 7(3), 2012
Abstract:
Gene promoter(s) specialized in root tissues is an important component for crop biotechnology. In our current study, we report results of promoter analysis of the HPX1, a gene expressed predominantly in roots. The HPX1 promoter regions were predicted, linked to the gfp reporter gene, and transformed into rice. Promoter activities were analyzed in various organs and tissues of six independent transgenic HPX1:gfp plants using the fluorescent microscopy and q-RT-PCR methods. GFP fluorescence levels were high in root elongation regions but not in root apex and cap of the HPX1:gfp plants. Very low levels of GFP fluorescence were observed in anthers and leaves. Levels of promoter activities were 16- to 190-fold higher in roots than in leaves of the HPX1:gfp plants. The HPX1 promoter directs high levels of gene expression in root tissues producing GFP levels up to 0.39 % of the total soluble protein. Thus, the HPX1 promoter is predominantly active in the root elongation region during the vegetative stage of growth.
Full text link https://tinyurl.com/bde82vm7
Article title: Analysis of the APX, PGD1 and R1G1B constitutive gene promoters in various organs over three homozygous generations of transgenic rice plants
Authors: Su-Hyun Park, Seung Woon Bang, Jin Seo Jeong, Harin Jung, Mark Christian Felipe Reveche Redillas, Hyung Il Kim, Kang Hyun Lee, Youn Shic Kim, Ju-Kon Kim
Publication title: Planta 235(6):1397-408, 2012
Abstract:
We have previously characterized the constitutively active promoters of the APX, PGD1 and R1G1B genes in rice (Park et al. 2010 in J Exp Bot 61:2459-2467). To have potential crop biotechnology applications, gene promoters must be stably active over many generations. In our current study, we report our further detailed analysis of the APX, PGD1 and R1G1B gene promoters in various organs and tissues of transgenic rice plants for three (T₃₋₅) homozygous generations. The copy numbers in 37 transgenic lines that harbor promoter:gfp constructs were determined and promoter activities were measured by real-time qPCR. Analysis of the 37 lines revealed that 15 contained a single copy of one of the three promoter:gfp chimeric constructs. The promoter activity levels were generally higher in multi-copy lines, whereas variations in these levels over the T₃₋₅ generations studied were observed to be smaller in single-copy than in multi-copy lines. The three promoters were further found to be highly active in the whole plant body at both the vegetative and reproductive stages of plant growth, with the exception of the APX in the ovary and R1G1B in the pistil and filaments where zero or very low levels of activity were detected. Of note, the spatial activities of the PGD1 promoter were found to be strikingly similar to those of the ZmUbi1, a widely used constitutive promoter. Our comparison of promoter activities between T₃, T₄ and T₅ plants revealed that the APX, PGD1 and R1G1B promoters maintained their activities at comparable levels in leaves and roots over three homozygous generations and are therefore potentially viable alternative promoters for crop biotechnology applications.
Full text link https://tinyurl.com/mw6vtfuy
Article title: Transgenic overexpression of UIP1, an interactor of the 3′ untranslated region of the Rubisco small subunit mRNA, increases rice tolerance to drought
Authors: Su-Hyun Park, Jin Seo Jeong, Mark C. F. R. Redillas, Harin Jung, Seung Woon Bang, Youn Shic Kim & Ju-Kon Kim
Publication title: Plant Biotechnology Reports 7(1), 2012
Abstract:
Gene regulation at the post-transcriptional level is a well-organized process to adjust plants in response to environmental changes. Here, we identified a novel RNA-binding protein (RBP) possessing a CBS (cystathionine-β-synthase) domain through yeast three-hybrid screening. This RBP, 3′-UTR-interacting protein 1 (UIP1), interacts with 3′ untranslated region of the Rubisco small subunit mRNA (3′ RbcS)—the major mRNA element that mediates the stress-induced mRNA decay (SMD) under drought and salt stress conditions. Six deletion constructs were made to delineate the binding domain of the UIP1 protein. Co-transformation of yeast with these constructs together with three different hybrid RNAs in various combinations showed that deletion of 51 N-terminal amino acids resulted in a loss of sequence-specific binding affinity. Further deletion at the region between 52 and 212 amino acids revealed that the CBS domain of UIP1 is necessary for binding to 3′ RbcS. Transgenic overexpression of UIP1 in rice resulted in an increase in tolerance to drought stress at the vegetative stage of growth. Under drought, high salt and low temperature conditions, the maximum photochemical efficiency of photosystem II (F v/F m) of UIP1 plants was higher than those of the nontransgenic plants. Interestingly, the effect of UIP1 overexpression on tolerance to stress was much more pronounced under drought than under high salt and low temperature conditions. Taken together, our results demonstrate that UIP1 interacts with 3′ untranslated region of RbcS1 mRNA and increases tolerance of transgenic overexpressors to drought stress.
Full text link https://tinyurl.com/58w9bsmf
Article title: Comparison of reactive porous media for sulfur-oxidizing denitrification of high nitrate strength wastewater
Authors: Grace M. Nisola, Mark C.F.R. Redillas, Eulsaeng Cho, Midoek Han, Namjong Yoo, Wook-Jin Chung
Publication title: Biochemical Engineering Journal 58(1):79-86, 2011
Abstract:
Three packing materials for sulfur oxidizing denitrification packed bed systems seeded with acclimated anoxic sludge were evaluated. Two porous media were prepared via thermal fusion with sodium bicarbonate as porogen: sulfur fused with powdered (1) calcium carbonate (CaCO3) (SCa) and (2) oyster shell (SCr). Randomly packed sulfur and limestone granules (S+L) media were used as the control. Results revealed that SCr is the most suitable media as it exhibited the highest nitrate removals and lowest nitrite accumulation. It has macrovoidal pores which facilitated microbial attachment. Additionally, SCr had the highest CaCO3 loading per unit volume and highest media dissolution rate which was favorable to avert pH decrease. But due to high denitrification activity, high sulfate levels in SCr may necessitate a post-treatment step prior to effluent discharge. Due to poor biomass attachment, S+L is most sensitive to change in fluid flow condition. As hydraulic retention time is decreased, S+L exhibited intensive and irreversible performance decline. Inferior denitrification performance of SCa was mainly due to low CaCO3 loading per unit volume, low dissolution kinetics and low alkalinity consumption by denitrifiers. Using modified Stover–Kincannon kinetic model, overall performance and denitrification capacities can be arranged as SCr>S+L>SCa.
Full text link https://tinyurl.com/mwj8adbx
Article title: NH3 gas absorption and bio-oxidation in a single bioscrubber system
Authors: Grace M. Nisola, Eulsaeng Cho, Jennica D. Orata, Mark C.F.R. Redillas, Danvir Mark C. Farnazo, Enkhdul Tuuguu, Wook Jin Chung
Publication title: Process Biochemistry 44(2):161-167, 2009
Abstract:
A combined ammonia gas absorption and nitrification was conducted in a single bioscrubber. The reactor was consisted of a bubble column (gas absorption) and a packed bed (nitrification) which contained poly-urethane foams with immobilized nitrifying activated sludge. The entering gas and scrubbing liquid were contacted countercurrently. The bubble column elimination capacity (EC) was 26.74 g NH3/m3 h at >99% ammonia gas removal and effluent gas concentration lower than 2 ppmv. Without ammonium supplement, EC can reach 35.66 g NH3/m3 h which is equivalently the highest tolerable ammonia loading rate of 700 g N/m3 day (1650 mg N/L) at the packed bed. At this level, 593 g N/m3-day ammonia removal rate was achieved via nitrification, dominated by ammonia oxidation. Partial recycling (R/Q = 0.5) of scrubbing solution reduced the secondary wastewater volume by producing 233% more concentrated nitrified products. Hydraulic retention time (HRT) of 24 h was found optimal for both processes (gas absorption and nitrification).
Full text link https://tinyurl.com/ms2urb9r