Application of Upstream Open Reading Frames (uORFs) Editing for the Development of Stress-Tolerant Crops.

Global population growth and climate change are posing increasing challenges to the production of a stable crop supply using current agricultural practices. The generation of genetically modified (GM) crops has contributed to improving crop stress tolerance and productivity; however, many regulations are still in place that limit their commercialization. Recently, alternative biotechnology-based strategies, such as gene-edited (GE) crops, have been in the spotlight. Gene-editing technology, based on the clustered regularly interspaced short palindromic repeats (CRISPR) platform, has emerged as a revolutionary tool for targeted gene mutation, and has received attention as a game changer in the global biotechnology market. Here, we briefly introduce the concept of upstream open reading frames (uORFs) editing, which allows for control of the translation of downstream ORFs, and outline the potential for enhancing target gene expression by mutating uORFs. We discuss the current status of developing stress-tolerant crops, and discuss uORF targets associated with salt stress-responsive genes in rice that have already been verified by transgenic research. Finally, we overview the strategy for developing GE crops using uORF editing via the CRISPR-Cas9 system. A case is therefore made that the mutation of uORFs represents an efficient method for developing GE crops and an expansion of the scope of application of genome editing technology.

OsCRP1, a Ribonucleoprotein Gene, Regulates Chloroplast mRNA Stability That Confers Drought and Cold Tolerance.

Chloroplast ribonucleoproteins (cpRNPs) are nuclear-encoded and highly abundant proteins that are proposed to function in chloroplast RNA metabolism. However, the molecular mechanisms underlying the regulation of chloroplast RNAs involved in stress tolerance are poorly understood. Here, we demonstrate that CHLOROPLAST RNA-BINDING PROTEIN 1 (OsCRP1), a rice (Oryza sativa) cpRNP gene, is essential for stabilization of RNAs from the NAD(P)H dehydrogenase (NDH) complex, which in turn enhances drought and cold stress tolerance. An RNA-immunoprecipitation assay revealed that OsCRP1 is associated with a set of chloroplast RNAs. Transcript profiling indicated that the mRNA levels of genes from the NDH complex significantly increased in the OsCRP1 overexpressing compared to non-transgenic plants, whereas the pattern in OsCRP1 RNAi plants were opposite. Importantly, the OsCRP1 overexpressing plants showed a higher cyclic electron transport (CET) activity, which is essential for elevated levels of ATP for photosynthesis. Additionally, overexpression of OsCRP1 resulted in significantly enhanced drought and cold stress tolerance with higher ATP levels compared to wild type. Thus, our findings suggest that overexpression of OsCRP1 stabilizes a set of mRNAs from genes of the NDH complex involved in increasing CET activity and production of ATP, which consequently confers enhanced drought and cold tolerance.

Over-expression of PsGPD, a mushroom glyceraldehyde-3-phosphate dehydrogenase gene, enhances salt tolerance in rice plants.

Transgenic potatoes expressing glyceraldehyde-3-phosphate dehydrogenase (GPD), isolated from the oyster mushroom, Pleurotus sajor-caju, had increased tolerance to salt stress (Jeong et al. Biochem Biophys Res Commun 278:192-196, 2000). To examine the physiological mechanisms enhancing salt tolerance in GPD-transgenic rice plants, the salt tolerance of five GPD transgenic rice lines (T1-T5) derived from Dongjin rice cultivar were evaluated in a fixed 150 mM saline environment in comparison to two known wild-type rice cultivars, Dongjin (salt sensitive) and Pokali (salt tolerant). Transgenic lines, T2, T3, and T5, had a substantial increase in biomass and relative water content compared to Dongjin. Stomatal conductance and osmotic potential were higher in the GPD transgenic lines and were similar to those in Pokali. The results are discussed based on the comparative physiological response of GPD transgenic lines with those of the salt-sensitive and salt-tolerant rice cultivars.

Determination of the variations in levels of phenolic compounds in soybean (Glycine max Merr.) sprouts infected by anthracnose (Colletotrichum gloeosporioides).

BACKGROUND: Soybean sprouts (Kongnamool) are one of the most popular and nutritive traditional vegetables in East Asia. Anthracnose caused by Colletotrichum gloeosporioides is one of the most serious diseases of soybean sprouts. In order to obtain basic information for breeding and/or selecting soybean genotypes with increased natural defense against anthracnose, phenolic compounds were profiled for healthy and infected soybean (Glycine max Merr.) sprouts by using high-performance liquid chromatography coupled with tandem mass spectrometry. RESULTS: Tryptophan and eight phenolic compounds (daidzin, genistin, malonyldaidzin, malonylgenistin, daidzein, glycitein, genistein and coumestrol) were determined from healthy and inoculated sprouts. Total identified phenolic content was 40.02 ± 0.03 mg kg⁻¹, 99.4% of which was isoflavones. CONCLUSION: The monitoring suggested that de novo induced glycitein appeared to act as a phytoalexin in the defence mechanism of the soybean sprouts against C. gloeosporioides, and constitutively formed seven phenolic components that functioned as phytoanticipins in the diseased soybean sprouts.

Identification and Characterization of Key Genes Responsible for Weedy and Cultivar Growth Types in Soybean.

In cultivated plants, shoot morphology is an important factor that influences crop economic value. However, the effects of gene expression patterns on shoot morphology are not clearly understood. In this study, the molecular mechanism behind shoot morphology (including leaf, stem, and node) was analyzed using RNA sequencing to compare weedy (creeper) and cultivar (stand) growth types obtained in F7 derived from a cross of wild and cultivated soybeans. A total of 12,513 (in leaves), 14,255 (in stems), and 11,850 (in nodes) differentially expressed genes were identified among weedy and cultivar soybeans. Comparative transcriptome and expression analyses revealed 22 phytohormone-responsive genes. We found that GIBBERELLIN 2-OXIDASE 8 (GA2ox), SPINDLY (SPY), FERONIA (FER), AUXIN RESPONSE FACTOR 8 (ARF8), CYTOKININ DEHYDROGENASE-1 (CKX1), and ARABIDOPSIS HISTIDINE KINASE-3 (AHK3), which are crucial phytohormone response genes, were mainly regulated in the shoot of weedy and cultivar types. These results indicate that interactions between phytohormone signaling genes regulate shoot morphology in weedy and cultivar growth type plants. Our study provides insights that are useful for breeding and improving crops to generate high-yield soybean varieties.

Rice microRNA171f/SCL6 module enhances drought tolerance by regulation of flavonoid biosynthesis genes.

Plants have evolved sophisticated defense systems to enhance drought tolerance. These include the microRNA (miRNA) group of small noncoding RNAs that act as post-transcriptional regulators; however, details of the mechanisms by which they confer drought tolerance are not well understood. Here, we show that osa-MIR171f, a member of osa-MIR171 gene family, is mainly expressed in response to drought stress and regulates the transcript levels of SCARECROW-LIKE6-I (SCL6-I) and SCL6-II in rice (Oryza sativa). The SCL6 genes are known to be involved in shoot branching and flag leaf morphology. Osa-MIR171f-overexpressing (osa-MIR171f-OE) transgenic plants showed reduced drought symptoms compared with non-transgenic (NT) control plants under both field drought and polyethylene glycol (PEG)-mediated dehydration stress conditions. Transcriptome analysis of osa-MIR171f-OE plants and osa-mir171f-knockout (K/O) lines generated by clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) revealed that osa-mature-miR171a-f (osa-miR171) regulates the expression of flavonoid biosynthesis genes, consequently leading to drought tolerance. This upregulation in the osa-MIR171f-OE plants, which did not occur in NT control plants, was observed under both normal and drought conditions. Our findings indicate that osa-miR171 plays a role in drought tolerance by regulating SCL6-I and SCL6-II transcript levels.

Endophytic Trichoderma isolates from tropical environments delay disease onset and induce resistance against Phytophthora capsici in hot pepper using multiple mechanisms.

Endophytic Trichoderma isolates collected in tropical environments were evaluated for biocontrol activity against Phytophthora capsici in hot pepper (Capsicum annuum). Six isolates were tested for parasitic and antimicrobial activity against P. capsici and for endophytic and induced resistance capabilities in pepper. Isolates DIS 70a, DIS 219b, and DIS 376f were P. capsici parasites, while DIS 70a, DIS 259j, DIS 320c, and DIS 376f metabolites inhibited P. capsici. All six isolates colonized roots but were inefficient stem colonizers. DIS 259j, DIS 320c, and DIS 376f induced defense-related expressed sequence tags (EST) in 32-day-old peppers. DIS 70a, DIS 259j, and DIS 376f delayed disease development. Initial colonization of roots by DIS 259j or DIS 376f induced EST with potential to impact Trichoderma endophytic colonization and disease development, including multiple lipid transferase protein (LTP)-like family members. The timing and intensity of induction varied between isolates. Expression of CaLTP-N, encoding a LTP-like protein in pepper, in N. benthamiana leaves reduced disease development in response to P. nicotianae inoculation, suggesting LTP are functional components of resistance induced by Trichoderma species. Trichoderma isolates were endophytic on pepper roots in which, depending on the isolate, they delayed disease development by P. capsici and induced strong and divergent defense reactions.

Decisive role of apurinic/apyrimidinic endonuclease/Ref-1 in initiation of cell death.

The apurinic/apyrimidinic endonuclease/redox effector factor-1 (APE/Ref-1) is involved in the base excision repair of apurinic/apyrimidinic sites induced by oxidative DNA damage. APE/Ref-1 was decreased by kainic acid (KA) injury in a time-dependent manner at the level of proteins, not transcripts. We investigated whether alteration of APE/Ref-1 amounts would influence hippocampal cell fate, survival or death, after KA injury. Overexpression of APE/Ref-1 using adenovirus and restoration of APE small peptides significantly reduced KA-induced hippocampal cell death. Both silencing of APE/Ref-1 by siRNA and inhibition of endonuclease by an antibody significantly increased caspase-3 activity and apoptotic cell death triggered from the early time after exposure to KA. These findings suggest that cell death is initiated by reducing APE/Ref-1 protein and inhibiting its repair function in spite of enough protein amounts. In conclusion, APE/Ref-1 may be a regulator of cell death initiation, and APE small peptides could provide molecular mechanism-based therapies for neuroprotection in progressive excitotoxic neuronal damage.

Sensitive and Specific Detection of Xanthomonas oryzae pv. oryzae by Real-Time Bio-PCR Using Pathovar-Specific Primers Based on an rhs Family Gene.

The present study describes bio-polymerase chain reaction (PCR) assays to detect bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae in rice. Successful control of X. oryzae. pv. oryzae requires a specific and reliable diagnostic tool. However, other X. oryzae pathovars are detected by currently available molecular and serological methods. In this study, SYBR Green real-time and conventional PCR primer sets were designed based on an rhs family gene of X. oryzae pv. oryzae KACC10331 because these genes are structurally diverse. The specificity of the primers was evaluated using purified DNA from 11 isolates of two X. oryzae pathovars, 21 other Xanthomonas species, and 4 other reference phytopathogenic bacteria and fungi. The assay was also able to detect at least two genome equivalents of cloned amplified target DNA using purified DNA. Thus, the SYBR Green real-time PCR-based method can be used for the rapid and specific detection of X. oryzae pv. oryzae and will potentially simplify and facilitate diagnosis and monitoring of this pathogen and guide plant disease management.

Physiological and photochemical evaluation of pepper methionine sulfoxide reductase B2 (CaMsrB2) expressing transgenic rice in saline habitat.

Two pepper methionine sulfoxide reductase B2 (CaMsrB2) gene expressing transgenic rice lines (L-8 and L-23) were interrogated with respect to their physiological and photochemical attributes along with control (WT, Ilmi) as a standard against varying levels of salt concentration which are 75 mM, 150 mM and 225 mM. Against various levels of salt (NaCl) concentration, recurring detrimental effects of extreme salt stress was observed and more pronounced in the wild type plants as compared to our transgenic lines. As the exacerbated effects of salinity is responsible for pushing the plants to their ecological tolerance, our transgenic lines performed well uplifted in different realms of physiology and photochemistry such as relative water content (RWC = 60-75%), stomatal conductance (gs = 70-190 mmolm-2s-1), performance index (PIABS = 1.0-4.5), maximal photochemical yield of PSII (FV/FM = 0.48-0.72) and chlorophyll content index (CCI = 5-7.2 au) in comparison to the control. Relative gene expression, ion analysis and antioxidants activity were analyzed in all treatments to ensure the hypothesis obtained from data of physiology and photochemistry. Photosynthetic apparatus is known to lose energy in various forms such as NPQ, DIO/CS, damages of reaction center (FV/FO) which are the markers of poor health were clearly decreased in the L-23 line as compared to L-8 and WT. Present study revealed the protruding tolerance of L-23 and L-8 transgenic lines with L-23 line in the lead in comparison to control and L-8 transgenic lines.

Physiological Aspects of Germination and Early Seedling Establishment of Pleurotus sajor-caju Glyceraldehyde-3-Phosphate Dehydrogenase Expressing Transgenic Rice in Saline Environment.

GPD encodes glyceraldehyde-3-phosphate dehydrogenase enzyme involved in sugar mobilization, particularly glycolysis and gluconeogenesis. The objective of this study was to determine physiological aspects of germination and early seedling establishment of PsGPD (Pleurotus sajor-caju glyceraldehyde-3-phosphate dehydrogenase) expressing transgenic rice (T5) against different salt concentrations. The T5 line that carried 2 copies of T-DNA and had the highest level of PsGPD expression was used in the investigation. Final germination percentage, amylase activity, reducing sugar accumulation, and chlorophyll biosynthesis were comparatively higher in PsGPD expressing transgenic rice against elevating saline conditions. A slow-paced conversion of porphyrin's precursors was seen through the matrix model and further elaborated by a graphical model. A sustained level of porphyrin was observed in PsGPD expressing transgenic rice. These data were concurrent with the relative gene expression and thermal imaging (thermography) of PsGPD expressing transgenic rice against salt stress. Morphological attributes also favored the salt tolerance exhibited by PsGPD-transformed rice.

The Rice GLYCINE-RICH PROTEIN 3 Confers Drought Tolerance by Regulating mRNA Stability of ROS Scavenging-Related Genes.

BACKGROUND: Plant glycine-rich proteins are categorized into several classes based on their protein structures. The glycine-rich RNA binding proteins (GRPs) are members of class IV subfamily possessing N-terminus RNA-recognition motifs (RRMs) and proposed to be involved in post-transcriptional regulation of its target transcripts. GRPs are involved in developmental process and cellular stress responses, but the molecular mechanisms underlying these regulations are still elusive. RESULTS: Here, we report the functional characterization of rice GLYCINE-RICH PROTEIN 3 (OsGRP3) and its physiological roles in drought stress response. Both drought stress and ABA induce the expression of OsGRP3. Transgenic plants overexpressing OsGRP3 (OsGRP3OE) exhibited tolerance while knock-down plants (OsGRP3KD) were susceptible to drought compared to the non-transgenic control. In vivo, subcellular localization analysis revealed that OsGRP3-GFP was transported from cytoplasm/nucleus into cytoplasmic foci following exposure to ABA and mannitol treatments. Comparative transcriptomic analysis between OsGRP3OE and OsGRP3KD plants suggests that OsGRP3 is involved in the regulation of the ROS related genes. RNA-immunoprecipitation analysis revealed the associations of OsGRP3 with PATHOGENESIS RELATED GENE 5 (PR5), METALLOTHIONEIN 1d (MT1d), 4,5-DOPA-DIOXYGENASE (DOPA), and LIPOXYGENASE (LOX) transcripts. The half-life analysis showed that PR5 transcripts decayed slower in OsGRP3OE but faster in OsGRP3KD, while MT1d and LOX transcripts decayed faster in OsGRP3OE but slower in OsGRP3KD plants. H2O2 accumulation was reduced in OsGRP3OE and increased in OsGRP3KD plants compared to non-transgenic plants (NT) under drought stress. CONCLUSION: OsGRP3 plays a positive regulator in rice drought tolerance and modulates the transcript level and mRNA stability of stress-responsive genes, including ROS-related genes. Moreover, OsGRP3 contributes to the reduction of ROS accumulation during drought stress. Our results suggested that OsGRP3 alleviates ROS accumulation by regulating ROS-related genes' mRNA stability under drought stress, which confers drought tolerance.

Three cases of Moraxella osloensis meningitis: a difficult experience in species identification and determination of clinical significance.

We had three cases of Moraxella osloensis meningitis. The species identification was impossible by conventional and commercial phenotypic tests. However, we could identify the species using the 16S rRNA gene sequencing. Determination of clinical significance was difficult in one patient. All three patients recovered by appropriate antimicrobial therapy.

A correlation between host-mediated expression of parasite genes as tandem inverted repeats and abrogation of development of female Heterodera glycines cyst formation during infection of Glycine max.

Host-mediated (hm) expression of parasite genes as tandem inverted repeats was investigated as a means to abrogate the formation of mature Heterodera glycines (soybean cyst nematode) female cysts during its infection of Glycine max (soybean). A Gateway-compatible hm plant transformation system was developed specifically for these experiments in G. max. Three steps then were taken to identify H. glycines candidate genes. First, a pool of 150 highly conserved H. glycines homologs of genes having lethal mutant phenotypes or phenocopies from the free living nematode Caenorhabditis elegans were identified. Second, annotation of those 150 genes on the Affymetrix soybean GeneChip allowed for the identification of a subset of 131 genes whose expression could be monitored during the parasitic phase of the H. glycines life cycle. Third, a microarray analyses identified a core set of 32 genes with induced expression (>2.0-fold, log base 2) during the parasitic stages of infection. H. glycines homologs of small ribosomal protein 3a and 4 (Hg-rps-3a [accession number CB379877] and Hg-rps-4 [accession number CB278739]), synaptobrevin (Hg-snb-1 [accession number BF014436]) and a spliceosomal SR protein (Hg-spk-1 [accession number BI451523.1]) were tested for functionality in hm expression studies. Effects on H. glycines development were observed 8 days after infection. Experiments demonstrated that 81-93% fewer females developed on transgenic roots containing the genes engineered as tandem inverted repeats. The effect resembles RNA interference. The methodology has been used here as an alternative approach to engineer resistance to H. glycines.

Differential expression of two glutamate transporters, GLAST and GLT-1, in an experimental rat model of glaucoma.

Glutamate is the major excitatory neurotransmitter of the mammalian retina, and excessive glutamate has been implicated in the pathogenesis of glaucoma. It is well known that glutamate transport, mainly via GLAST and GLT-1, is cardinal mechanism for maintaining glutamate homeostasis in normal and pathological conditions, including ischemia in the brain. In an effort to understand the role of glutamate and the glutamate regulation system of the retina in the pathogenesis of glaucoma, we examined changes in the expression of two glutamate transporters, GLAST and GLT-1, by Western blot analysis and immunocytochemistry in a rat glaucoma model. GLT-1 was expressed in cone photoreceptors and some cone bipolar cells and the levels of expression were significantly increased in the cauterized eyes throughout the entire experimental period. In contrast, GLAST expression, which occurred in Müller cells, the main retinal glial cells, remained stable during the experimental period. These results suggest that GLT-1 may be a prerequisite for the maintenance of glutamate homeostasis in the retina undergoing glaucoma.

Distribution and diversity of bacterial endophytes from four Pinus species and their efficacy as biocontrol agents for devastating pine wood nematodes.

In this study, we isolated a total of 238 culturable putative bacterial endophytes from four Pinus species (Pinus densiflora, P. koraiensis, P. rigida, and P. thunbergii) across 18 sampling sites in Korea. The samples were cultured in de Man Rogosa Sharpe and humic acid-vitamin agar media. These selective media were used to isolate lactic acid bacteria and Actinobacteria, respectively. Analysis using 16S ribosomal DNA sequencing grouped the isolated putative bacterial endophytes into 107 operational taxonomic units (OTUs) belonging to 48 genera. Gamma-proteobacteria were the most abundant bacteria in each sampling site and three tissues (needle, stem and root). The highest OTU richness and diversity indices were observed in the roots, followed by stem and needle tissues. Total metabolites extracted from three isolates (two isolates of Escherichia coli and Serratia marcescens) showed significant nematicidal activity against the pine wood nematode (Bursaphelenchus xylophilus). Our findings demonstrated the potential use of bacterial endophytes from pine trees as alternative biocontrol agents against pine wood nematodes.

Expression Analysis of Sound Vibration-Regulated Genes by Touch Treatment in Arabidopsis.

Sound vibration (SV) is considered to be a mechanical stimulus which gives rise to various physiological and molecular changes in plants. Previously, we identified 17 SV-regulated genes (SRGs) which were up-regulated by SV treatments in Arabidopsis. Here, we analyzed the expression pattern of similar genes after an exposure of 500 Hertz at 80 decibels, for various time periods. Simultaneously, we confirmed the SV-mediated expression of these genes under lighted condition as many of them were reported to be dark-induced. For this, we designed an improved SV treatment chamber. Additionally, we checked the electrolyte leakage (EL), photosynthetic performance and expression of mechanosensitive (MS) ion channel genes after 5 days of SV treatment in the illuminated chamber. EL was higher, and the photosynthetic performance index was lower in the SV-treated plants compared to control. Seven out of the 13 MS ion channel genes were differentially expressed after the SV treatment. Simultaneously, we checked the touch-mediated expression pattern of 17 SRGs and 13 MS ion channel genes. The distinct expression pattern of 6 SRGs and 1 MS ion channel gene generate an idea that SV as a stimulus is different from touch. Developmental stage-specific expression profiling suggested that the majority of the SRGs were expressed spatiotemporally in different developmental stages of Arabidopsis, especially in imbibed seed, seedlings and leaves.

Positive regulatory role of sound vibration treatment in Arabidopsis thaliana against Botrytis cinerea infection.

Sound vibration (SV), a mechanical stimulus, can trigger various molecular and physiological changes in plants like gene expression, hormonal modulation, induced antioxidant activity and calcium spiking. It also alters the seed germination and growth of plants. In this study, we investigated the effects of SV on the resistance of Arabidopsis thaliana against Botrytis cinerea infection. The microarray analysis was performed on infected Arabidopsis plants pre-exposed to SV of 1000 Hertz with 100 decibels. Broadly, the transcriptomic analysis revealed up-regulation of several defense and SA-responsive and/or signaling genes. Quantitative real-time PCR (qRT-PCR) analysis of selected genes also validated the induction of SA-mediated response in the infected Arabidopsis plants pre-exposed to SV. Corroboratively, hormonal analysis identified the increased concentration of salicylic acid (SA) in the SV-treated plants after pathogen inoculation. In contrast, jasmonic acid (JA) level in the SV-treated plants remained stable but lower than control plants during the infection. Based on these findings, we propose that SV treatment invigorates the plant defense system by regulating the SA-mediated priming effect, consequently promoting the SV-induced resistance in Arabidopsis against B. cinerea.

Pleurotus sajor-caju HSP100 complements a thermotolerance defect in hsp104 mutant Saccharomyces cerevisiae.

A putative Hsp100 gene was cloned from the fungus Pleurotus sajor-caju. mRNA expression studies demonstrated that this gene (designated PsHsp100) is highly induced by high temperature,induced less strongly by exposure to ethanol, and not induced by drought or salinity. Heat shock induction is detectable at 37 degrees C and reaches a maximum level at 42 degrees C. PsHsp100 mRNA levels sharply increased within 15 min of exposure to high temperature, and reached a maximum expression level at 2 h that was maintained for several hours. These results indicate that PsHsp100 could work at an early step in thermotolerance. To examine its function, PsHsp100 was transformed into a temperature-sensitive hsp104 deletion mutant Saccharomycetes cerivisiae strain to test the hypothesis that PsHSP100 is an protein that functions in thermotolerance. Overexpression of PsHSP100 complemented the thermotolerance defect of the hsp104 mutant yeast, allowing them being survive even at 50 degree C for 4 h. These results indicate that PsHSP100 protein is functional as an HSP100 in yeast and could play and important role in thermotolerance in P. sajor-caju.

Relationship between bilateral temporal hypometabolism and EEG findings for mesial temporal lobe epilepsy: analysis of 18F-FDG PET using SPM.

PURPOSE: To investigate the clinical significance of bilateral temporal hypometabolism (BTH) for patients with mesial temporal lobe epilepsy (MTLE) by using statistical parametric mapping (SPM). METHODS: Interictal 18F-FDG PET scans were performed for 29 patients with surgically treated MTLE. Clinical data, interictal epileptiform discharges (IEDs), ictal scalp EEG and intracarotid amobarbital test (IAT) were analyzed. To assess an 18F-FDG PET image, an SPM analysis as well as visual interpretation were applied. RESULTS: In 9 of 29 patients, the 18F-FDG PET scan revealed BTH by the SPM analysis, while only 3 patients showed BTH by the visual assessment. When the patients were classified into the unilateral temporal hypometabolism (UTH) and BTH groups based on the SPM results, bitemporal IEDs occurred significantly more frequently in the BTH group than in the UTH group (66.7% versus 22.2%). Bilateral independent seizure onset seen on the scalp EEG and bitemporal epilepsy were present only in the BTH group. Lateralized ictal onset was present less frequently in the BTH group than in the UTH group (44.4% versus 83.3%). There was no statistically significant difference in age at onset, duration of epilepsy, generalized seizure, history of febrile convulsion and CNS infection, lateralization throughout the whole tracing, lateralization on the IAT test, and surgical outcome between the UTH and BTH groups. CONCLUSION: Bilaterality of the EEG findings correlated with BTH on 18F-FDG PET by the SPM method. Our results suggest that analysis of 18F-FDG PET by using SPM may have a role in predicting those patients with bitemporal excitability or bitemporal independent epileptogenicity, and these patients should be monitored carefully.