44 research outputs found
The bacterial community structure and functional profile in the heavy metal contaminated paddy soils, surrounding a nonferrous smelter in South Korea
Funding Information: The authors wish to thank the Basic Science Research Program of the National Research Foundation (NRF) under the Ministry of Education, Science and Technology (2015R1A2A1A05001885), South Korea for providing funding support toward the completion of this study. This study was supported partially by the Estonian Ministry of Education and Research (Grant IUT2–16), and by the European Regional Development Fund through the Centre of Excellence EcolChange. We thank Saale Truu for the assistance in computer graphics. Funding Information: National Research Foundation of Korea, Grant/Award Number: 2015R1A2A1A05001885; Estonian Ministry of Education and Research, Grant/ Award Number: IUT2–16; European Region Development Fund Publisher Copyright: © 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.Peer reviewedPublisher PD
The Rice SPOTTED LEAF4 (SPL4) Encodes a Plant Spastin That Inhibits ROS Accumulation in Leaf Development and Functions in Leaf Senescence
Lesion mimic mutants (LMMs) are usually controlled by single recessive mutations that cause the formation of necrotic lesions without pathogen invasion. These genetic defects are useful to reveal the regulatory mechanisms of defense-related programmed cell death in plants. Molecular evidence has been suggested that some of LMMs are closely associated with the regulation of leaf senescence in rice (Oryza sativa). Here, we characterized the mutation underlying spotted leaf4 (spl4), which results in lesion formation and also affects leaf senescence in rice. Map-based cloning revealed that the gamma ray-induced spl4-1 mutant has a single base substitution in the splicing site of the SPL4 locus, resulting in a 13-bp deletion within the encoded microtubule-interacting-and-transport (MIT) spastin protein containing an AAA-type ATPase domain. The T-DNA insertion spl4-2 mutant exhibited spontaneous lesions similar to those of the spl4-1 mutant, confirming that SPL4 is responsible for the LMM phenotype. In addition, both spl4 mutants exhibited delayed leaf yellowing during dark-induced or natural senescence. Western blot analysis of spl4 mutant leaves suggested possible roles for SPL4 in the degradation of photosynthetic proteins. Punctate signals of SPL4-fused fluorescent proteins were detected in the cytoplasm, similar to the cellular localization of animal spastin. Based on these findings, we propose that SPL4 is a plant spastin that is involved in multiple aspects of leaf development, including senescence
HyperCLOVA X Technical Report
We introduce HyperCLOVA X, a family of large language models (LLMs) tailored
to the Korean language and culture, along with competitive capabilities in
English, math, and coding. HyperCLOVA X was trained on a balanced mix of
Korean, English, and code data, followed by instruction-tuning with
high-quality human-annotated datasets while abiding by strict safety guidelines
reflecting our commitment to responsible AI. The model is evaluated across
various benchmarks, including comprehensive reasoning, knowledge, commonsense,
factuality, coding, math, chatting, instruction-following, and harmlessness, in
both Korean and English. HyperCLOVA X exhibits strong reasoning capabilities in
Korean backed by a deep understanding of the language and cultural nuances.
Further analysis of the inherent bilingual nature and its extension to
multilingualism highlights the model's cross-lingual proficiency and strong
generalization ability to untargeted languages, including machine translation
between several language pairs and cross-lingual inference tasks. We believe
that HyperCLOVA X can provide helpful guidance for regions or countries in
developing their sovereign LLMs.Comment: 44 pages; updated authors list and fixed author name
Mutation of ONAC096 Enhances Grain Yield by Increasing Panicle Number and Delaying Leaf Senescence during Grain Filling in Rice
Exploring genetic methods to improve yield in grain crops such as rice (Oryza sativa) is essential to help meet the needs of the increasing population. Here, we report that rice ONAC096 affects grain yield by regulating leaf senescence and panicle number. ONAC096 expression increased rapidly in rice leaves upon the initiation of aging- and dark-induced senescence. Two independent T-DNA insertion mutants (onac096-1 and onac096-2) with downregulated ONAC096 expression retained their green leaf color during natural senescence in the field, thus extending their photosynthetic capacity. Reverse-transcription quantitative PCR analysis showed that ONAC096 upregulated genes controlling chlorophyll degradation and leaf senescence. Repressed OsCKX2 (encoding cytokinin oxidase/dehydrogenase) expression in the onac096 mutants led to a 15% increase in panicle number without affecting grain weight or fertility. ONAC096 mediates abscisic acid (ABA)-induced leaf senescence by upregulating the ABA signaling genes ABA INSENSITIVE5 and ENHANCED EM LEVEL. The onac096 mutants showed a 16% increase in grain yield, highlighting the potential for using this gene to increase grain production
Senescence-Induced Serotonin Biosynthesis and Its Role in Delaying Senescence in Rice Leaves1[C][W][OA]
Serotonin, which is well known as a pineal hormone in mammals, plays a key role in conditions such as mood, eating disorders, and alcoholism. In plants, although serotonin has been suggested to be involved in several physiological roles, including flowering, morphogenesis, and adaptation to environmental changes, its regulation and functional roles are as yet not characterized at the molecular level. In this study, we found that serotonin is greatly accumulated in rice (Oryza sativa) leaves undergoing senescence induced by either nutrient deprivation or detachment, and its synthesis is closely coupled with transcriptional and enzymatic induction of the tryptophan biosynthetic genes as well as tryptophan decarboxylase (TDC). Transgenic rice plants that overexpressed TDC accumulated higher levels of serotonin than the wild type and showed delayed senescence of rice leaves. However, transgenic rice plants, in which expression of TDC was suppressed through an RNA interference (RNAi) system, produced less serotonin and senesced faster than the wild type, suggesting that serotonin is involved in attenuating leaf senescence. The senescence-retarding activity of serotonin is associated with its high antioxidant activity compared to either tryptophan or chlorogenic acid. Results of TDC overexpression and TDC RNAi plants suggest that TDC plays a rate-limiting role for serotonin accumulation, but the synthesis of serotonin depends on an absolute amount of tryptophan accumulation by the coordinate induction of the tryptophan biosynthetic genes. In addition, immunolocalization analysis revealed that serotonin was abundant in the vascular parenchyma cells, including companion cells and xylem-parenchyma cells, suggestive of its involvement in maintaining the cellular integrity of these cells for facilitating efficient nutrient recycling from senescing leaves to sink tissues during senescence
Inactivating transcription factor OsWRKY5 enhances drought tolerance through abscisic acid signaling pathways
During crop cultivation, water-deficit conditions retard growth, thus reducing crop productivity. Therefore, uncovering the mechanisms behind drought tolerance is a critical task for crop improvement. Here, we show that the rice (Oryza sativa) WRKY transcription factor OsWRKY5 negatively regulates drought tolerance. We determined that OsWRKY5 was mainly expressed in developing leaves at the seedling and heading stages, and that its expression was reduced by drought stress and by treatment with NaCl, mannitol, and abscisic acid (ABA). Notably, the genome-edited loss-of-function alleles oswrky5-2 and oswrky5-3 conferred enhanced drought tolerance, measured as plant growth under water-deficit conditions. Conversely, the overexpression of OsWRKY5 in the activation-tagged line oswrky5-D resulted in higher susceptibility under the same conditions. The loss of OsWRKY5 activity increased sensitivity to ABA, thus promoting ABA-dependent stomatal closure. Transcriptome deep sequencing and reverse transcription quantitative polymerase chain reaction analyses demonstrated that the expression of abiotic stress-related genes including rice MYB2 (OsMYB2) was upregulated in oswrky5 knockout mutants and downregulated in oswrky5-D mutants. Moreover, dual-luciferase, yeast one-hybrid, and chromatin immunoprecipitation assays showed that OsWRKY5 directly binds to the W-box sequences in the promoter region of OsMYB2 and represses OsMYB2 expression, thus downregulating genes downstream of OsMYB2 in the ABA signaling pathways. Our results demonstrate that OsWRKY5 functions as a negative regulator of ABA-induced drought stress tolerance, strongly suggesting that inactivation of OsWRKY5 or manipulation of key OsWRKY5 targets could be useful to improve drought tolerance in rice cultivars.Y
Functional Analysis of the Amine Substrate Specificity Domain of Pepper Tyramine and Serotonin N-Hydroxycinnamoyltransferases
Pepper (Capsicum annuum) serotonin N-hydroxycinnamoyltransferase (SHT) catalyzes the synthesis of N-hydroxycinnamic acid amides of serotonin, including feruloylserotonin and p-coumaroylserotonin. To elucidate the domain or the key amino acid that determines the amine substrate specificity, we isolated a tyramine N-hydroxycinnamoyltransferase (THT) gene from pepper. Purified recombinant THT protein catalyzed the synthesis of N-hydroxycinnamic acid amides of tyramine, including feruloyltyramine and p-coumaroyltyramine, but did not accept serotonin as a substrate. Both the SHT and THT mRNAs were found to be expressed constitutively in all pepper organs. Pepper SHT and THT, which have primary sequences that are 78% identical, were used as models to investigate the structural determinants responsible for their distinct substrate specificities and other enzymatic properties. A series of chimeric genes was constructed by reciprocal exchange of DNA segments between the SHT and THT cDNAs. Functional characterization of the recombinant chimeric proteins revealed that the amino acid residues 129 to 165 of SHT and the corresponding residues 125 to 160 in THT are critical structural determinants for amine substrate specificity. Several amino acids are strongly implicated in the determination of amine substrate specificity, in which glycine-158 is involved in catalysis and amine substrate binding and tyrosine-149 plays a pivotal role in controlling amine substrate specificity between serotonin and tyramine in SHT. Furthermore, the indisputable role of tyrosine is corroborated by the THT-F145Y mutant that uses serotonin as the acyl acceptor. The results from the chimeras and the kinetic measurements will direct the creation of additional novel N-hydroxycinnamoyltransferases from the various N-hydroxycinnamoyltransferases found in nature
Inhibition of STAT6 Activation by AS1517499 Inhibits Expression and Activity of PPARγ in Macrophages to Resolve Acute Inflammation in Mice
Signal transducer and activator of transcription 6 (STAT6) promotes an anti-inflammatory process by inducing the development of M2 macrophages. We investigated whether modulating STAT6 activity in macrophages using AS1517499, the specific STAT6 inhibitor, affects the restoration of homeostasis after an inflammatory insult by regulating PPARγ expression and activity. Administration of AS1517499 suppressed the enhanced STAT6 phosphorylation and nuclear translocation observed in peritoneal macrophages after zymosan injection. In addition, AS1517499 delayed resolution of acute inflammation as evidenced by enhanced secretion of pro-inflammatory cytokines, reduced secretion of anti-inflammatory cytokines in PLF and supernatants from peritoneal macrophages, and exaggerated neutrophil numbers and total protein levels in PLF. We demonstrate temporal increases in annexin A1 (AnxA1) protein and mRNA levels in peritoneal lavage fluid (PLF), peritoneal macrophages, and spleen in a murine model of zymosan-induced acute peritonitis. In vitro priming of mouse bone marrow-derived macrophages (BMDM) and peritoneal macrophages with AnxA1 induced STAT6 activation with enhanced PPARγ expression and activity. Using AS1517499, we demonstrate that inhibition of STAT6 activation delayed recovery of PPARγ expression and activity, as well as impaired efferocytosis. Taken together, these results suggest that activation of the STAT6 signaling pathway mediates PPARγ expression and activation in macrophages to resolve acute inflammation