Sex: Female
Education:
- Doctor of Philosophy in Bioengineering Sciences, Nagoya University
Field of Specialization:
Plant Physiology
Plant Breeding
Abiotic Stress Tolerance
Plant Genetics
Epigenetics
Researches:
Article title: Genome-wide Association Mapping for the Identification of SNPs Controlling Lateral Root Plasticity in Selected Rice Germplasms of the Philippines
Authors: Jonathan M. Niones, Patrick Louie G. Lipio, Antoinette S. Cruz, Maria Corazon J. Cabral, Desiree M. Hautea, Nonawin Lucob-Agustin
Publication title: Philippine Journal of Science 150(3): 663-674, June 2021
Abstract:
Lateral root plasticity is a key adaptive mechanism for drought and fluctuating moisture-induced stresses in rice. Thus, understanding the genetic control of lateral root plasticity is important to enhance the climate-resilience and productivity of rice in abiotic stressed-prone environments. Genome-wide association analysis was conducted on a selected panel of traditional rice varieties (TRVs) to find single nucleotide polymorphisms (SNPs) associated with root plasticity traits under different gradients of soil moisture stress. A total of 17 SNPs, which were significantly correlated to root plasticity traits under soil moisture stress conditions, were located in six chromosomes (2, 5, 7, 9, 10, and 12). Additionally, the accessions that showed high plasticity in total lateral root length (TLRL) under severe drought were identified from among the TRVs and assumed to possess the lone SNP associated with the trait found in Chromosome 2. Specifically, the Baksalan Kawalwal accession showed an increase in L-type lateral root length under fluctuating soil moistures (SMF) (+10.31 m) and progressive drought (PDR) (+0.90 m), relative to their continuously waterlogged (CWL) counterparts under rootbox pinboard system. This may suggest the performance of the SNP in controlling the promotion of lateral roots. Furthermore, a possible candidate gene found near the SNP in Chromosome 2 is a member of PYR/PYL/RCAR-like protein family of abscisic acid (ABA) receptors, likely suggesting that plasticity in lateral root development in rice under severe drought could be regulated by ABA. Taken together, these novel root plasticity SNPs and the respective candidate genes on Chromosome 2 have potential use in developing climate-smart rice varieties.
Full text link https://tinyurl.com/4uu7a37j
Article title: The outstanding rooting1 mutation gene maintains shoot growth and grain yield through promoting root development in rice under water deficit field environments
Authors: T. Hasegawa, C. M. Wainaina, A. Shibata, N. Lucob-Agustin, D. Makihara, et al.
Publication title: Journal of Agronomy and Crop Science, June 2021
Abstract:
Drought is one of the most serious constraints to rice cultivation, even under alternate wetting and drying (AWD), which is a water-saving management practice. In rice, enhanced root development is essential for stable shoot growth, adaptability and productivity under water deficit environments. We identified and characterized outstanding rooting1 (our1) rice mutant using hydroponics. The present study sought to examine morphological root traits of the our1 mutant and the role of the mutation gene in shoot growth and yield under AWD. Thus, we evaluated the growth performance of the our1 rice mutant in pot experiments and under field AWD conditions in Kenya. The experiments were conducted with our1 mutant, its wild type and their progenies under both AWD and continuously waterlogged (CWL) conditions. The our1 mutant possessed a well-developed root system and exhibited particularly enhanced thin root development, which was maintained from the early vegetative stage through the reproductive stage under both pot and field AWD management. This enhanced root development promoted shoot growth through increased water uptake during rewatered conditions between drought periods in AWD. In addition, the our1 mutant showed enhanced shoot growth during the reproductive stage, resulting in the maintenance of yield under AWD fields. Genotypes harbouring our1 mutation gene showed higher yields compared to wild-type genotypes which was attributed to their higher photosynthetic ability as a result of enhanced root activity. These results suggest the important role of a well-developed root system architecture and enhanced root function in stabilizing rice yields under water-limited environments. Our findings indicate that the our1 mutation gene can serve as a novel breeding material to mitigate the impact of transient drought stress on yield under AWD.
Full text available upon request to the author
Article title: Mutation of OUR1/OsbZIP1, which encodes a member of the basic leucine zipper transcription factor family, promotes root development in rice through repressing auxin signaling
Authors: Tomomi Hasegawa, Nonawin Lucob-Agustin, Koki Yasufuku, Takaaki Kojima, Shunsaku Nishiuchi, et al.
Publication title: Plant Science 306:110861, May 2021
Abstract:
A well-developed root system is essential for efficient water uptake, particularly in drought-prone environments. However, the molecular mechanisms underlying the promotion of root development are poorly understood. We identified and characterized a rice mutant, outstanding rooting1 (our1), which exhibited a well-developed root system. The our1 mutant displayed typical auxin-related phenotypes, including elongated seminal root and defective gravitropism. Seminal root elongation in the our1 mutant was accelerated via the promotion of cell division and elongation. In addition, compared with the wild type, the density of short and thin lateral roots (S-type LRs) was reduced in the our1 mutant, whereas that of long and thick LRs (L-type LRs) was increased. Expression of OUR1, which encodes OsbZIP1, a member of the basic leucine zipper transcription factor family, was observed in the seminal root tip and sites of LR emergence, wherein attenuation of reporter gene expression levels controlled by the auxin response promoter DR5 was also observed in the our1 mutant. Taken together, our results indicate that the our1 gene promotes root development by suppressing auxin signaling, which may be a key factor contributing to an improvement in root architecture.
Full text available upon request to the author
Article title: Morpho-physiological and molecular mechanisms of phenotypic root plasticity for rice adaptation to water stress conditions
Authors: Nonawin Lucob-Agustin, Tsubasa Kawai, Mana Kano-Nakata, Roel R Suralta, Jonathan M Niones, et al.
Publication title: Breeding Science 71(1): 20-29, February 2021
Abstract:
Different types of water stress severely affect crop production, and the plant root system plays a critical role in stress avoidance. In the case of rice, a cereal crop cultivated under the widest range of soil hydrologic conditions, from irrigated anaerobic conditions to rainfed conditions, phenotypic root plasticity is of particular relevance. Recently, important plastic root traits under different water stress conditions, and their physiological and molecular mechanisms have been gradually understood. In this review, we summarize these plastic root traits and their contributions to dry matter production through enhancement of water uptake under different water stress conditions. We also discuss the physiological and molecular mechanisms regulating the phenotypic plasticity of root systems.
Full text available upon request to the author
Article title: Rice MEDIATOR25, OsMED25, is an essential subunit for jasmonate-mediated root development and OsMYC2-mediated leaf senescence
Authors: Go Suzuki, Nonawin Lucob-Agustin, Keita Kashihara, Yumi Fujii, Yoshiaki Inukai, et al.
Publication title: Plant Science 306:110853, May 2021
Abstract:
The Mediator multiprotein complex acts as a universal adaptor between transcription factors (TFs) and RNA polymerase II. MEDIATOR25 (MED25) has an important role in jasmonic acid (JA) signaling in Arabidopsis. However, no research has been conducted on the role of MED25 in JA signaling in rice, which is one of the most important food crops globally and is a model plant for molecular studies in other monocotyledonous species. In the present study, we isolated the loss-of function mutant of MED25, osmed25, through the map-based cloning and phenotypic complementation analysis by the introduction of OsMED25 and investigated the role of OsMED25 in JA signaling in rice. The osmed25 mutants had longer primary (seminal) roots than those of the wild-type (WT) and exhibited JA-insensitive phenotypes. S-type lateral root densities in osmed25 mutants were lower than those in the WT, whereas L-type lateral root densities in osmed25 mutants were higher than those in the WT. Furthermore, the osmed25 mutants retarded JA-regulated leaf senescence under dark-induced senescence. Mutated osmed25 protein could not interact with OsMYC2, which is a positive TF in JA signaling in rice. The expression of JA-responsive senescence-associated genes was not upregulated in response to JA in the osmed25 mutants. The results suggest that OsMED25 participates in JA-mediated root development and OsMYC2-mediated leaf senescence in rice.
Full text available upon request to the author
Article title: The promoted lateral root 1 (plr1) mutation is involved in reduced basal shoot starch accumulation and increased root sugars for enhanced lateral root growth in rice
Authors: Nonawin Lucob-Agustin, Daisuke Sugiura, Mana Kano-Nakata, Tomomi Hasegawa, et al.
Publication title: Plant Science 301:110667, December 2021
Abstract:
Lateral roots (LRs) are indispensable for plant growth, adaptability and productivity. We previously reported a rice mutant, exhibiting a high density of thick and long LRs (L-type LRs) with long parental roots and herein referred to as promoted lateral root1 (plr1). In this study, we describe that the mutant exhibited decreased basal shoot starch accumulation, suggesting that carbohydrates might regulate the mutant root phenotype. Further analysis revealed that plr1 mutation gene regulated reduced starch accumulation resulting in increased root sugars for the regulation of promoted LR development. This was supported by the exogenous glucose application that promoted L-type LRs. Moreover, nitrogen (N) application was found to reduce basal shoot starch accumulation in both plr1 mutant and wild-type seedlings, which was due to the repressed expression of starch biosynthesis genes. However, unlike the wild-type that responded to N treatment only at seedling stage, the plr1 mutant regulated LR development under low to increasing N levels, both at seedling and higher growth stages. These results suggest that plr1 mutation gene is involved in reduced basal shoot starch accumulation and increased root sugar level for the promotion of L-type LR development, and thus would be very useful in improving rice root architecture.
Full text available upon request to the author
Article title: WEG1, which encodes a cell wall hydroxyproline‐rich glycoprotein, is essential for parental root elongation controlling lateral root formation in rice
Authors: Nonawin Lucob‐Agustin, Tsubasa Kawai, Misuzu Takahashi‐Nosaka, Mana Kano‐Nakata, Cornelius M Wainaina, Tomomi Hasegawa, et al.
Publication title: Physiologia plantarum 169(2): 214-227, June 2020
Abstract:
Lateral roots (LRs) determine the overall root system architecture, thus enabling plants to efficiently explore their underground environment for water and nutrients. However, the mechanisms regulating LR development are poorly understood in monocotyledonous plants. We characterized a rice mutant, wavy root elongation growth 1 (weg1), that produced higher number of long and thick LRs (L-type LRs) formed from the curvatures of its wavy parental roots caused by asymmetric cell growth in the elongation zone. Consistent with this phenotype, was the expression of the WEG1 gene, which encodes a putative member of the hydroxyproline-rich glycoprotein family that regulates cell wall extensibility, in the root elongation zone. The asymmetric elongation growth in roots is well known to be regulated by auxin, but we found that the distribution of auxin at the apical region of the mutant and the wild-type roots was symmetric suggesting that the wavy root phenotype in rice is independent of auxin. However, the accumulation of auxin at the convex side of the curvatures, the site of L-type LR formation, suggested that auxin likely induced the formation of L-type LRs. This was supported by the need of a high amount of exogenous auxin to induce the formation of L-type LRs. These results suggest that the MNU-induced weg1 mutated gene regulates the auxin-independent parental root elongation that controls the number of likely auxin-induced L-type LRs, thus reflecting its importance in improving rice root architecture.
Full text link https://tinyurl.com/pupved9s
Article title: Enhanced root system development responses of a newly identified mutation gene promoting lateral root development to various nitrogen conditions in rice
Authors: Nonawin Lucob-Agustin, Tomomi Hasegawa, Kyosuke Jinno, Roel R. Suralta, Jonathan M. Niones, et al.
Publication title: Journal of International Cooperation for Agricultural Development 18:48-55, 2020
Abstract:
Lateral roots (LRs), which largely constitute the root system, allow the entire root system to expand to a larger area to efficiently capture water and nutrients from the soil. Thus, the optimization of LRs should be considered for the genetic improvement of root system architecture to most notably impact plant acquisition of soil resources for productivity. In this study, we newly identified a rice mutant, 11NB10, which has a high number of thick, long, and highly branched LRs (L-type LRs) with promoted parental root growth. We evaluated the root performance of this mutant under various nitrogen (N) regimes, including 30, 60, and 120 mg N corresponding to low, standard, and high N conditions, respectively. The results showed that under low N conditions, the 11NB10 mutant had a larger root system based on its total root length, which increased further with increasing N levels, compared to its wild-type, Nipponbare. This promoted root system growth could be attributed to the development of highly branched L-type LRs, which in turn might contributed to higher leaf area and shoot dry matter production. These findings suggest that the 11NB10 mutation gene promotes a highly developed root system under low N conditions, and its root performance could be further improved by enhancing LR development through N application. Thus, the 11NB10 mutant is a promising line for the breeding programs targeting root system architecture in rice.
Full text link https://tinyurl.com/4h49c3kd
Article title: Evaluation of a Newly Identified Mutation Gene that Promotes Root Elongation for Improvement of Drought Avoidance in Rice
Authors: Tomomi Hasegawa, Akihide Shibata, Cornelius Mbathi Wainaina, Nonawin Lucob-Agustin, Daigo Makihara, et al.
Publication title: Journal of International Cooperation for Agricultural Development 17:34-40, 2019
Abstract:
Drought is one of the most serious abiotic stresses for rice cultivation, even under a water saving production system such as the Alternate Wetting and Drying (AWD) system and upland irrigated fields. In this study, we evaluated the performance of larger root systems in a KM07 mutant under such water management conditions. This mutant line was utilized for breeding and development of new rice germplasm adaptable to drought stress conditions in Mwea, Kenya, by crossing it with the recurrent parent of New Rice for Africa (NERICA), WAB56-104. Three mutant-type F6 lines grown under AWD and upland irrigated conditions showed different responses to drought stress. The mutant type’s greater root growth was observed in lines 2 and 3 under AWD and upland irrigation conditions, respectively. These results suggest that the highly developed root system derived from the KM07 mutant can avoid drought stress under field conditions in Kenya, and it should be utilized as breeding material for drought stress avoidance, along with water management technology. Key words: Kenya, rice, root system, drought, water saving technology
Full text link https://tinyurl.com/m4zatsua
Article title: Functional roles of the plasticity in deep root system development in soil water uptake and dry matter production of doubled haploid lines of rice under upland drought condition.
Authors: R.R. Suralta, N.B. Lucob, A.B. Aguelo, J.M. Niones, M.C.J. Cabral, et al.
Publication title: International Journal of Agricultural Technology 13(6):907-925, 2017
Abstract:
Soil moisture fluctuation (SMF) stress due to erratic rainfall in rainfed lowland (RFL) rice ecosystems negatively affect production. Under such condition, root plasticity is one of the key traits that play important roles for plant adaptation. This study aimed to evaluate root plasticity expression and its functional roles in water uptake, dry matter production and yield under SMF using three chromosome segment substitution lines (CSSLs) with major genetic background of KDML105 and a common substituted segment in chromosome 8. The CSSLs showed greater shoot dry matter production than KDML105 under SMF, which was attributed to the maintenance of stomatal conductance resulting in higher grain yield. The root system development based on total root length of the CSSLs were significantly higher than that of KDML105 due to the promoted production of nodal and lateral roots. These results implied that the common substituted segments in chromosome 8 of the 3 CSSLs may be responsible for the expression of their root plasticity under SMF and contributed to the increase in water uptake and consequently dry matter production and yield. These CSSLs could be used as a good source of genetic material for drought resistance breeding programs targeting rainfed lowland condition with fluctuating soil moisture environments and for further genetic studies to elucidate mechanisms underlying root plasticity.
Full text link https://tinyurl.com/2whhubjt
Article title: Developmental and quantitative trait loci analyses of root plasticity in response to soil moisture fluctuation in rice
Authors: Roel R. Suralta, Nonawin B. Lucob, Loida M. Perez, Jonathan M. Niones, Henry T. Nguyen
Publication title: Philippine Journal of Crop Science 40(2): 12-24, August 2015
Abstract:
Soil moisture fluctuation (SMF) stress, such as transient waterlogged-to-drought conditions and vice versa, negatively affect the productivity of rainfed lowland rice. This study was conducted to quantify root plastic developmental responses of doubled-haploid lines (DHLs) to soil moisture fluctuation stress and analyze the quantitative trait loci (QTL) associated with such plasticity. Ninety DHLs and their parents, CT9993 and IR62266, were grown under continuously waterlogged (CWL) and SMF conditions. Plasticity was calculated as the difference between the mean values of the trait between SMF and CWL grown plants for each DHL. Among component root traits, the number of L-type lateral roots (LR) had the greatest promotion under SMF, which greatly contributed to the plasticity in total LR length. and hence total root length especially at deeper soil layer. Thirty QTLs for different root plasticity traits under SMF were detected at different soil depths, which explained about 8.3 to 20.9% of the total phenotypic variations. Three QTLs (qPLLR(20)-3 and qPTLLR(20)-7 at 10-20 cm soil depth, and qPLLR(30)-2 at 20-30 cm soil depth) associated with the plasticity in the number of L-type LR were detected in chromosomes 3, 7 and 2, respectively. The plasticity of correlated component-root traits, such as between the number of nodal roots and total nodal root length, and between total lateral root length and total root length at certain soil depth, have QTLs overlapping in the same regions, suggesting their possible similar genetic controls under SMF. The root plasticity QTLs for the number and length of L-type LR did not overlap in any of the chromosomal regions, indicating that the plasticity expressions of these two traits have different genetic controls under SMF.
Full text link https://tinyurl.com/62dnhb4w
Article title: Evaluation of deep rooting and branching ability soil water uptake and dry matter production of selected double-haploid lines of rice under drought stress
Authors: N.B. Lucob, M.A. Ramos, P.T. Vizmonte Jr, R.R. Suralta
Publication title: Philippine Journal of Crop Science, 2013
Abstract:
Drought is the most serious abiotic stress that limits crop production in rainfed upland rice ecosystem. This study was conducted to validate the functions of deep rooting and branching ability in maintaining productivity of selected DHLs under drought condition. The genotypes used were DHL parents (CT9993 and IR62266) and selected DHLs (38, 141, 142, 40, 61, 70, 103, 113, 44, 50 and 57) grown under three soil moisture conditions: WW (well watered maintained at 20% SMC), DO (drought-stress without 5-cm thick gravel level at 30 cm soil depth) and D30 (drought stress with 5 cm gravel layer at 30 cm soil depth). Results showed that shoot dry weight and different root system development (RSD) responses were reduced by DO and D30 but the measured traits were generally not significantly different between drought treatments. Hence, D30 can precisely evaluate the functional contributions of root system developed below the gravel layer to water uptake and dry matter production. Total root length (TRL), total nodal root length (TNRL) and total lateral root length (TLRL) at all soil depths in D30 were not significantly different among genotypes. However, these root traits that developed below the gravel layer showed significant genotypic variations. The TRL and TLRL had significant functional contribution to transpiration and dry matter production while the deepest nodal root length (dNRL) and mean NRL had no contribution. This implied that RSD interms of lateral roo
t branching is more important than deep rooting ability to sustain soil water uptake under progressive drought stress. The TLRL below the gravel layer, however, had low relationship with dry matter production. The authors expect that the relationship would be improve if they have accounted the dry matter produced during the period of drought stress only which is subject for further study.
Full text available upon request to the author