Risk of depression in amyotrophic lateral sclerosis: A nationwide cohort study in South Korea.

Depression is frequently reported in amyotrophic lateral sclerosis (ALS) due to the disastrous prognosis of progressive motor impairment, but the risk of depression in ALS is still unclear. Therefore, we investigated the risk of depression in ALS and analyzed the effect of ALS-related physical disability on the risk of developing depression using the Korean National Health Insurance Service (KNHIS) database. A total of 2241 ALS patients, as defined by the International Classification Diseases (ICD, G12.21) and Rare Intractable Disease codes (V123), and 1:10 sex- and age-matched controls were selected from the KNHIS. After applying exclusion criteria (non-participation in national health screening, history of depression, or having missing data), 595 ALS patients and 9896 non-ALS individuals were finally selected. Primary outcome is newly diagnosed depression during follow-up duration defined by ICD code (F32 or F33). A Cox regression model was used to examine the hazard ratios (HRs) after adjustment for potential confounders. During the follow-up period, 283 cases of depression in the ALS group and 1547 in the controls were recorded. The adjusted HR for depression in ALS was 9.1 (95% confidence interval [CI] 7.87-10.60). The risk of depression was slightly higher in the disabled ALS group (aHR 10.1, 95% CI 7.98-12.67) than in the non-disabled ALS group (aHR 8.78, 95% CI 7.42-10.39). The relative risk of depression was higher in younger patients than in older patients, and in obese patients than in non-obese patients. Our study showed that ALS patients have an increased risk of depression compared to non-ALS individuals.

Isolated abducens nerve palsy following upper respiratory infection in a patient with ipsilateral chronic sphenoid sinusitis.

The abducens nerve, which is vulnerable because of its complex anatomy at the skull base, is seldom affected by acute or severe sphenoid sinusitis. Notably, abducens nerve palsy following asymptomatic chronic rhinosinusitis (CRS) in a healthy young individual after a mild upper respiratory infection (URI) remains undocumented in the literature. Herein, we report a case of acute unilateral abducens neuropathy in a healthy 35-year-old woman with CRS in the ipsilateral sphenoid sinus, following a mild URI 2 weeks earlier. She presented with sudden-onset diplopia, was afebrile, and had normal serum inflammatory biomarkers. Comprehensive ophthalmological and neurological exams revealed no abnormalities except limited lateral gaze in the left eye. Imaging revealed mucosal swelling on the hyperpneumatized left sphenoid sinus, which thinned the clivus and positioned the inflamed mucosa close to the Dorello's canal, likely facilitating the spread of inflammation to the ipsilateral abducens nerve. Urgent endoscopic sinus surgery combined with systemic corticosteroids and antibiotics led to complete resolution by postoperative day 10. The present case demonstrates acute abducens nerve neuropathy from URI-induced exacerbation of sphenoid sinus CRS with specific anatomical predispositions.

Usefulness of the MFIS-K, FSS, and FACIT-F Fatigue Scales in Korean Patients With MS, NMOSD, and MOGAD.

BACKGROUND AND PURPOSE: Fatigue is common in demyelinating disorders of the central nervous system (CNS), including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). We aimed to validate the usefulness of the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and the Fatigue Severity Scale (FSS) relative to the Korean version of the Modified Fatigue Impact Scale (MFIS-K) in Korean patients with MS, NMOSD, and MOGAD. METHODS: There were 294 patients with MS (n=120), NMOSD (n=103), or MOGAD (n=71) enrolled in a prospective demyelinating CNS registry. Fatigue was measured using the FACIT-F, MFIS-K, and FSS. Sleep quality, quality of life, depression, and pain were evaluated using the Pittsburgh Sleep Quality Index (PSQI), 36-item Short-Form Survey (SF-36), and Beck Depression Inventory-II (BDI-II). RESULTS: The MFIS-K, FACIT-F, and FSS scores showed high internal consistencies and strong correlations with each other in the MS, NMOSD, and MOGAD groups. The scores on all three fatigue scales were correlated with PSQI, SF-36, and BDI-II results in the three groups. The areas under the receiver operating characteristic curves for the FSS and FACIT-F were 0.834 and 0.835, respectively, for MS, 0.877 and 0.833 for NMOSD, and 0.925 and 0.883 for MOGAD. CONCLUSIONS: These results suggest that the MFIS-K, FSS, and FACIT-F are useful and valuable assessment instruments for evaluating fatigue in Korean patients with MS, NMOSD, and MOGAD.

Migraine Risk in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder: A Nationwide Cohort Study in South Korea.

INTRODUCTION: Although the relationship between migraine and multiple sclerosis (MS) has been reported, the risk of migraine in MS and neuromyelitis optica spectrum disorder (NMOSD) is unclear. Therefore, this study investigated the risk of migraine in the Korean MS and NMOSD populations. METHODS: This study analyzed claims data from 1,492 patients with MS and 1,551 patients with NMOSD based on diagnostic codes in the Korean National Health Insurance Service. Migraine risk was compared with a control group (matched 1:5 for age, sex, and comorbidities) using Cox proportional hazards analysis. Patients aged <20 years and with previous migraine were excluded. RESULTS: Migraine risk was higher in patients with MS (adjusted hazard ratio [aHR] 1.37; 95% confidence interval [CI]: 1.15-1.62) but did not differ significantly in patients with NMOSD (aHR 1.05; 95% CI: 0.87-1.27) compared to controls. No significant sex-based differences in migraine risk were observed. Patients with NMOSD showed decreasing risk with age (p for interaction = 0.040). Comorbidities like hypertension, diabetes, or dyslipidemia did not significantly alter migraine risk in either group. CONCLUSION: The study results revealed an increased risk of migraines in patients with MS but not in patients with NMSOD compared with matched controls.

Synergizing breeding strategies via combining speed breeding, phenotypic selection, and marker-assisted backcrossing for the introgression of Glu-B1i in wheat.

Wheat is a major food crop that plays a crucial role in the human diet. Various breeding technologies have been developed and refined to meet the increasing global wheat demand. Several studies have suggested breeding strategies that combine generation acceleration systems and molecular breeding methods to maximize breeding efficiency. However, real-world examples demonstrating the effective utilization of these strategies in breeding programs are lacking. In this study, we designed and demonstrated a synergized breeding strategy (SBS) that combines rapid and efficient breeding techniques, including speed breeding, speed vernalization, phenotypic selection, backcrossing, and marker-assisted selection. These breeding techniques were tailored to the specific characteristics of the breeding materials and objectives. Using the SBS approach, from artificial crossing to the initial observed yield trial under field conditions only took 3.5 years, resulting in a 53% reduction in the time required to develop a BC2 near-isogenic line (NIL) and achieving a higher recurrent genome recovery of 91.5% compared to traditional field conditions. We developed a new wheat NIL derived from cv. Jokyoung, a leading cultivar in Korea. Milyang56 exhibited improved protein content, sodium dodecyl sulfate-sedimentation value, and loaf volume compared to Jokyoung, which were attributed to introgression of the Glu-B1i allele from the donor parent, cv. Garnet. SBS represents a flexible breeding model that can be applied by breeders for developing breeding materials and mapping populations, as well as analyzing the environmental effects of specific genes or loci and for trait stacking.

Morphometric assessment of tibial nerve and its branches around the ankle.

It is essential to understand the considerable variations in bifurcation patterns of the tibial nerve (TN) and its peripheral nerves at the level of the tarsal tunnel to prevent iatrogenic nerve injury during surgical nerve release or nerve block. A total of 16 ankles of 8 human cadavers were dissected to investigate the branching patterns of the TN, using 2 imaginary lines passing through the tip of the medial malleolus (MM) as reference lines. Bifurcation patterns and detailed information on the relative locations of the medial plantar, lateral plantar, medial calcaneal, and inferior calcaneal nerves to the reference lines were recorded. The most common bifurcation pattern was Type 1 in 12 ankles (75%), followed by Type 2 in 2 ankles (13%). One medial calcaneal nerve (MCN) was seen in 11 (69%) specimens and 2 MCN branches were seen in 5 (31%) specimen. 88% of the MCN branches bifurcated from the TN, whereas 6% originated from both TN and lateral plantar nerve (LPN). At the level of the tip of the MM, 2 of 7 parameters showed statistically significant difference between both sexes (P < .05). There was a statistically significant difference between left and right ankles in 2 of 7 measurements (P < .05). Further morphometric analysis of the width, distance, and angle between the TN branches and the tip of MM showed a highly variable nature of the location of the peripheral nerve branches.

Risk of depression and anxiety in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study in South Korea.

BACKGROUND: We investigated the risks of depression/anxiety in patients with multiple sclerosis (pwMS) or patients with neuromyelitis optica spectrum disorder (pwNMOSD). OBJECTIVES: MS/NMOSD cohorts were collected from Korean National Health Insurance Service, using the International Classification of Diseases-10th and information on Rare Intractable Disease program. Patients who were younger than 20 years, had a previous depression/anxiety, or died in the index year were excluded. METHODS: Hazard ratios (HRs) of depression/anxiety in pwMS and pwNMOSD from controls matched 1:5 for age, sex, hypertension, diabetes, and dyslipidemia were calculated using Cox regressions with a 1-year lag period and estimated over time. RESULTS: During a mean follow-up of 4.1 years, adjusted hazard ratios (aHR) for depression were 3.25 (95% confidence interval (CI) = 2.59-4.07) in MS and 2.17 (1.70-2.76) in NMOSD, and aHRs for anxiety were 1.83 (1.49-2.23) in MS and 1.56 (1.26-1.91) in NMOSD. The risks of anxiety/depression did not differ between MS and NMOSD and were highest in the second year after diagnosis of MS/NMOSD. The relative risk of depression was higher in younger pwMS/pwNMOSD, and the relative risk of anxiety was higher in pwMS who was male, had low income, or lived in a non-urban area. CONCLUSION: The risk of depression and anxiety was increased in pwMS/pwNMOSD.

Evaluation of SARS-CoV-2 Vaccine-Induced Antibody Responses in Patients with Neuroimmunological Disorders: A Real-World Experience.

This study evaluates the antibody responses to SARS-CoV-2 vaccines in patients with neuroimmunological disorders (pwNID) who are receiving immunomodulating treatments, compared to healthy individuals. It included 25 pwNID with conditions such as optic neuritis, neuromyelitis optica spectrum disorder, multiple sclerosis, myasthenia gravis, and polymyositis, as well as 56 healthy controls. All participants had completed their full SARS-CoV-2 vaccination schedule, and their blood samples were collected within six months of their last dose. The concentration of anti-SARS-CoV-2 IgG antibodies was measured using an enzyme-linked immunosorbent assay. The results showed that pwNID had significantly lower antibody titers (58.4 ± 49.2 RU/mL) compared to healthy individuals (81.7 ± 47.3 RU/mL). This disparity persisted even after adjusting for age and the interval between the final vaccination and sample collection. A notable correlation was found between the use of immunomodulating treatments and reduced antibody levels, whereas mRNA vaccines were linked to higher antibody concentrations. The conclusion of this study is that immunomodulating treatments may reduce the effectiveness of SARS-CoV-2 vaccines in pwNID. This insight is crucial for healthcare providers in designing vaccination strategies and managing treatment plans for pwNID on immunomodulating therapies, highlighting the need for personalized approaches in this subgroup.

The risk of type 2 diabetes mellitus in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study.

BACKGROUND AND OBJECTIVES: An association has been suggested between premorbid type 2 diabetes mellitus (T2DM) and the risk of multiple sclerosis (MS). However, little is known about the risk of developing T2DM in MS and neuromyelitis optica spectrum disorder (NMOSD). This study aimed to determine the T2DM risk in patients with MS and NMSOD. METHODS: The Korean National Health Insurance Service database was analyzed, and 1,801 and 1,721 adults with MS and NMOSD, respectively, who were free of T2DM between January 2010 and December 2017, were included. Matched controls were selected based on age, sex, and the presence of hypertension and dyslipidemia. RESULTS: The risk of developing T2DM was 1.54 times higher in NMOSD than in the controls (adjusted hazard ratio [aHR], 95 % confidence interval [CI] = 1.20-1.96). However, increased T2DM risk was not observed in MS (aHR = 1.13, 95 % CI = 0.91-1.42). The T2DM risk in patients with NMOSD was higher in those who received steroid treatment (aHR = 1.77, 95 % CI = 1.36-2.30) but not in those who did not (aHR = 0.59, 95 % CI = 0.24-1.43, p for interaction = 0.02). DISCUSSION: T2DM risk was increased in NMOSD but not in MS. Administering steroid treatment to patients with NMOSD may increase their T2DM risk.

OsLRR-RLP2 Gene Regulates Immunity to Magnaporthe oryzae in Japonica Rice.

Rice is an important cereal crop worldwide, the growth of which is affected by rice blast disease, caused by the fungal pathogen Magnaporthe oryzae. As climate change increases the diversity of pathogens, the disease resistance genes (R genes) in plants must be identified. The major blast-resistance genes have been identified in indica rice varieties; therefore, japonica rice varieties with R genes now need to be identified. Because leucine-rich repeat (LRR) domain proteins possess R-gene properties, we used bioinformatics analysis to identify the rice candidate LRR domain receptor-like proteins (OsLRR-RLPs). OsLRR-RLP2, which contains six LRR domains, showed differences in the DNA sequence, containing 43 single-nucleotide polymorphisms (SNPs) in indica and japonica subpopulations. The results of the M. oryzae inoculation analysis indicated that indica varieties with partial deletion of OsLRR-RLP2 showed susceptibility, whereas japonica varieties with intact OsLRR-RLP2 showed resistance. The oslrr-rlp2 mutant, generated using clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), showed increased pathogen susceptibility, whereas plants overexpressing this gene showed pathogen resistance. These results indicate that OsLRR-RLP2 confers resistance to rice, and OsLRR-RLP2 may be useful for breeding resistant cultivars.

Acceleration of wheat breeding: enhancing efficiency and practical application of the speed breeding system.

BACKGROUND: Crop breeding should be accelerated to address global warming and climate change. Wheat (Triticum aestivum L.) is a major food crop. Speed breeding (SB) and speed vernalization (SV) techniques for spring and winter wheat have recently been established. However, there are few practical examples of these strategies being used economically and efficiently in breeding programs. We aimed to establish and evaluate the performance of a breeder-friendly and energy-saving generation acceleration system by modifying the SV + SB system. RESULTS: In this study, a four-generation advancement system for wheat (regardless of its growth habits) was established and evaluated using an energy-efficient extended photoperiod treatment. A glasshouse with a 22-hour photoperiod that used 10 h of natural sunlight and 12 h of LED lights, and minimized temperature control during the winter season, was successful in accelerating generation. Even with one or two field tests, modified speed breeding (mSB) combined with a speed vernalization system (SV + mSB) reduced breeding time by more than half compared to traditional field-based methods. When compared to the existing SV + SB system, the SV + mSB system reduced energy use by 80% to maintain a 22-hour photoperiod. Significant correlations were found between the SV + mSB and field conditions in the number of days to heading (DTH) and culm length (CL). Genetic resources, recombinant inbred lines, and breeding materials that exhibited shorter DTH and CL values under SV + mSB conditions showed the same pattern in the field. CONCLUSIONS: The results of our SV + mSB model, as well as its practical application in wheat breeding programs, are expected to help breeders worldwide incorporate generation acceleration systems into their conventional breeding programs.

Increased risk of myocardial infarction in amyotrophic lateral sclerosis: A nationwide cohort study in South Korea.

BACKGROUND: The risk of myocardial infarction (MI), the major form of CVD, in amyotrophic lateral sclerosis (ALS) is currently unknown. We investigated the risk of MI in ALS and analyzed the effect of ALS-related physical disability on the risk of MI using the Korean National Health Insurance Service database. METHODS: A total of 659 ALS patients and 10,927 non-ALS participants were finally selected between January 1, 2011, and December 31, 2015. A Cox hazard regression model was used to examine the hazard ratios (HRs) for MI in ALS after adjustment for potential confounders. RESULTS: The incidence rate of MI was 26.2 per 1000 person-years, and the adjusted HR (aHR) for MI in ALS patients was 10.6 (95% confidence interval [CI] 7.2-15.4) compared with the controls. ALS patients who developed physical disability had an even higher risk of MI (aHR 18.6, 95% CI 11.5-30.0) compared with those who did not develop disability (aHR 7.4, 95% CI 4.6-11.9). The increased risk of MI was more prominent in female subjects than in male subjects (aHR 17.8, 95% CI 10.8-29.4 vs. aHR 6.9, 95% CI 4.1-11.6, P for interaction 0.006) and in obese subjects than in non-obese subjects (aHR 17.8, 95% CI 10.5-30.1 vs. aHR 7.9, 95% CI 4.9-12.8, P for interaction 0.018). CONCLUSIONS: Our findings suggest that the risk of MI is high in ALS patients compared with a control population, and the risk is more prominent in those who develop physical disability, or who are female or obese.

Clinical characteristics of myelin oligodendrocyte glycoprotein antibody-associated disease according to their epitopes.

Background: The detection of myelin oligodendrocyte glycoprotein autoantibodies (MOG-Ab) is essential for the diagnosis of MOG-Ab-associated disease (MOGAD). The clinical implications of different epitopes recognized by MOG-Ab are largely unknown. In this study, we established an in-house cell-based immunoassay for detecting MOG-Ab epitopes and examined the clinical characteristics of patients with MOG-Ab according to their epitopes. Methods: We conducted a retrospective review of patients with MOG-Ab-associated disease (MOGAD) in our single center registry, and collected serum samples from enrolled patients. Human MOG variants were generated to detect epitopes recognized by MOG-Ab. The differences in clinical characteristics according to the presence of reactivity to MOG Proline42 (P42) were evaluated. Results: Fifty five patients with MOGAD were enrolled. Optic neuritis was the most common presenting syndrome. The P42 position of MOG was a major epitope of MOG-Ab. The patients with a monophasic clinical course and childhood-onset patients were only observed in the group that showed reactivity to the P42 epitope. Conclusion: We developed an in-house cell-based immunoassay to analyze the epitopes of MOG-Ab. The P42 position of MOG is the primary target of MOG-Ab in Korean patients with MOGAD. Further studies are needed to determine the predictive value of MOG-Ab and its epitopes.

Novel index, neutrophil percentage (%) is a useful marker for disease activity in MOG antibody-associated disease.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a CNS autoimmune disease affecting the brain, spinal cord, and optic nerve. The neutrophil-to-lymphocyte ratio (NLR) is related to autoimmune disease activity. However, the clinical implication of index ratios such as the NLR is unclear in patients with MOGAD. OBJECTIVES: We investigated the relationship between index ratios such as the NLR and disease activity and disability to discover the index that best correlates with an attack in MOGAD. METHODS: Using a CNS demyelinating disease cohort, we reviewed 39 patients with MOGAD (age 37.4 ± 12.0 years; F:M = 20:19) who had 390 blood samples available for cell count analysis. We calculated the NLR, eosinophil-to-lymphocyte-ratio (ELR), platelet-to-lymphocyte-ratio (PLR), monocyte-to-lymphocyte ratio (MLR), basophil-to-lymphocyte ratio (BLR), and neutrophil percentage (N%) [neutrophil count (/mm3) / WBC (/mm3) x 100 (%)]. We investigated the associations between each index ratio and disease activity and disability using the receiver operating characteristic (ROC) curve, machine learning program (kNN algorithm), and generalized estimating equations (GEE) analysis. RESULTS: In patients with MOGAD, the NLR, PLR, and N% were higher and ELR was lower during an attack than in remission (all p<0.001). The areas under the ROC curve for the NLR, ELR, PLR, and N% were 0.68, 0.69, 0.61, and 0.68, respectively, with the highest sensitivity of 76.0% in the ELR and the highest specificity of 76.3% in the N%. The classification accuracy scores of the kNN machine learning algorithm were 71% for the NLR, 62% for the ELR, 63% for the PLR, and 72% for the N%. In the GEE analysis of attack samples, both the NLR and treatment-naive had positive associations with the Expanded Disability Status Scale (EDSS) score (ß=0.137, p = 0.008 and ß=1.142, p = 0.003, respectively), and the PLR was negatively associated with the EDSS score (ß=-0.004, p = 0.022). DISCUSSION: Our study suggests that the novel index, neutrophil% is the simplest and the most useful marker to differentiate between attack and remission and shows comparable reliability with NLR in MOGAD. Moreover, the NLR and PLR could be used as supportive biomarkers for disease disability during an attack in patients with MOGAD.

Epicranial headache part 1: Primary stabbing headache.

BACKGROUND/OBJECTIVE: Primary stabbing headache is a common but under-recognized primary headache disorder. The objectives of this review were to provide practical information for better understanding and identification of the disease, suggest an algorithm for differential diagnosis, and provide an insight into the pathophysiology of primary stabbing headache hypothesized from its clinical course. METHODS: This narrative review of primary stabbing headache is based on a literature search and the authors' clinical reasoning. RESULT: The phenotype of each stab is typically abrupt, ultrashort-lasting (<3 s), focal or multifocal, paroxysms of pain occurring sporadically or in clusters. The diagnosis of primary stabbing headache is clinical; fixed or migrating stabs without background pain or sensory abnormalities and the absence of features suggestive of other disorders (e.g., cranial autonomic symptoms or signs) can aid in the diagnosis of primary stabbing headache. The clinical patterns include monophasic, intermittent, and chronic primary stabbing headache, of which the first two are considered typical. The pathophysiology of primary stabbing headache has not yet been elucidated. In this review, we postulated the mechanism of stabbing headache, based on the pain phenotype and clinical course, and provide a clinical algorithm for the differential diagnosis of primary stabbing headache. CONCLUSION: Knowledge about the typical manifestations and clinical patterns of primary stabbing headache will aid in the proper diagnosis and differential diagnosis. Treatment should be tailored by considering the clinical patterns. Further research is needed to elucidate the pathophysiological mechanisms and optimal treatment of primary stabbing headache.

Increased Risk of Developing Depression in Disability after Stroke: A Korean Nationwide Study.

Stroke is a leading cause of mortality and a major cause of disability worldwide. A significant number of stroke survivors suffer from depression, impeding the activities of daily living and rehabilitation. Here, we examined the risk of depression among stroke survivors according to the severity of disabilities and compared its incidence with a matched control group. We included data from the Korean National Health Insurance Service of 207,678 stroke survivors. Cox proportional hazard models were used to calculate the risk of depression among stroke survivors. Stroke survivors had a greater risk of developing depression than the matched control group with an adjusted hazard ratio of 2.12 (95% confidence interval 2.09-2.15). Stroke survivors with more severe disabilities were associated with a higher risk of depression than those with mild disabilities. The risk of developing depression was prominently high within the first year after a stroke. Males and younger people (<65 years) were independent risk factors for depression in stroke survivors. This study demonstrated an increased risk of developing depression in stroke survivors compared to control subjects, and a higher risk of depression was associated with a more severe degree of disability. Clinicians should be aware of the risk of depression developing in stroke survivors, especially those with disabilities.

Multi-omics analysis reveals the genetic basis of rice fragrance mediated by betaine aldehyde dehydrogenase 2.

INTRODUCTION: Fragrance is an important economic and quality trait in rice. The trait is controlled by the recessive gene betaine aldehyde dehydrogenase 2 (BADH2) via the production of 2-acetyl-1-pyrroline (2AP). OBJECTIVES: Variation in BADH2 was evaluated at the population, genetic, transcriptional, and metabolic levels to obtain insights into fragrance regulation in rice. METHODS: Whole-genome resequencing of the Korean World Rice Collection of 475 rice accessions, including 421 breeding lines and 54 wild accessions, was performed. Transcriptome analyses of a subset of 279 accessions, proteome analyses of 64 accessions, and volatile profiling of 421 breeding lines were also performed. RESULTS: We identified over 3.1 million high-quality single nucleotide polymorphisms (SNPs) in Korean rice collection. Most SNPs were present in intergenic regions (79%), and 190,148 SNPs (6%) were located in the coding sequence, of which 53% were nonsynonymous. In total, 38 haplotypes were identified in the BADH2 coding region, including four novel haplotypes (one in cultivated and three in wild accessions). Tajima's D values suggested that BADH2 was under balancing selection in japonica rice. Furthermore, we identified 316 expression quantitative trait loci (eQTL), including 185 cis-eQTLs and 131 trans-eQTLs, involved in BADH2 regulation. A protein quantitative trait loci (pQTL) analysis revealed the presence of trans-pQTLs; 13 pQTLs were mapped 1 Mbp from the BADH2 region. Based on variable importance in projection (VIP) scores, 15 volatile compounds, including 2AP, discriminated haplotypes and were potential biomarkers for rice fragrance. CONCLUSION: We generated a catalog of haplotypes based on a resequencing analysis of a large number of rice accessions. eQTLs and pQTLs associated with BADH2 gene expression and protein accumulation are likely involved in the regulation of 2AP variation in fragrant rice. These data improve our understanding of fragrance and provide valuable information for rice breeding.

Mutations in OsDET1, OsCOP10, and OsDDB1 confer embryonic lethality and alter flavonoid accumulation in Rice (Oryza sativa L.) seed.

Morphological and biochemical changes accompanying embryogenesis and seed development are crucial for plant survival and crop productivity. Here, we identified a novel yellowish-pericarp embryo lethal (yel) mutant of the japonica rice cultivar Sindongjin (Oryza sativa L.), namely, yel-sdj. Seeds of the yel-sdj mutant showed a yellowish pericarp and black embryo, and were embryonic lethal. Compared with wild-type seeds, the yel-sdj mutant seeds exhibited significantly reduced grain size, grain weight, and embryo weight, and a remarkably lower rate of embryo retention in kernels subjected to milling. However, the volume of air space between embryo and endosperm, density of embryo, and total phenolic content (TPC) and antioxidant activity of mature grains were significantly higher in the yel-sdj mutant than in the wild type. Genetic analysis and mapping revealed that the yel-sdj mutant was non-allelic to the oscop1 null mutants yel-hc, yel-cc, and yel-sk, and its phenotype was controlled by a single recessive gene, LOC_Os01g01484, an ortholog of Arabidopsis thaliana DE-ETIOLATED 1 (DET1). The yel-sdj mutant carried a 7 bp deletion in the second exon of OsDET1. Seeds of the osdet1 knockout mutant, generated via CRISPR/Cas9-based gene editing, displayed the yel mutant phenotype. Consistent with the fact that OsDET1 interacts with CONSTITUTIVE PHOTOMORPHOGENIC 10 (OsCOP10) and UV-DAMAGED DNA BINDING PROTEIN 1 (OsDDB1) to form the COP10-DET1-DDB1 (CDD), seeds of oscop10 and osddb1 knockout mutants also showed the yel phenotype. These findings will enhance our understanding of the functional roles of OsDET1 and the CDD complex in embryogenesis and flavonoid biosynthesis in rice seeds.