Physiological and Molecular Mechanisms of Rice Tolerance to Salt and Drought Stress: Advances and Future Directions.

Rice, a globally important food crop, faces significant challenges due to salt and drought stress. These abiotic stresses severely impact rice growth and yield, manifesting as reduced plant height, decreased tillering, reduced biomass, and poor leaf development. Recent advances in molecular biology and genomics have uncovered key physiological and molecular mechanisms that rice employs to cope with these stresses, including osmotic regulation, ion balance, antioxidant responses, signal transduction, and gene expression regulation. Transcription factors such as DREB, NAC, and bZIP, as well as plant hormones like ABA and GA, have been identified as crucial regulators. Utilizing CRISPR/Cas9 technology for gene editing holds promise for significantly enhancing rice stress tolerance. Future research should integrate multi-omics approaches and smart agriculture technologies to develop rice varieties with enhanced stress resistance, ensuring food security and sustainable agriculture in the face of global environmental changes.

Identification of a key locus, qNL3.1, associated with seed germination under salt stress via a genome-wide association study in rice.

KEY MESSAGE: Two causal OsTTL and OsSAPK1 genes of the key locus qNL3.1 significantly associated with seed germination under salt stress were identified via a genome-wide association study, which could improve rice seed germination under salt stress. Rice is a salt-sensitive crop, and its seed germination determines subsequent seedling establishment and yields. In this study, 168 accessions were investigated for the genetic control of seed germination under salt stress based on the germination rate (GR), germination index (GI), time at which 50% germination was achieved (T50) and mean level (ML). Extensive natural variation in seed germination was observed among accessions under salt stress. Correlation analysis showed significantly positive correlations among GR, GI and ML and a negative correlation with T50 during seed germination under salt stress. Forty-nine loci significantly associated with seed germination under salt stress were identified, and seven of these were identified in both years. By comparison, 16 loci were colocated with the previous QTLs, and the remaining 33 loci might be novel. qNL3.1, colocated with qLTG-3, was simultaneously identified with the four indices in two years and might be a key locus for seed germination under salt stress. Analysis of candidate genes showed that two genes, the similar to transthyretin-like protein OsTTL and the serine/threonine protein kinase OsSAPK1, were the causal genes of qNL3.1. Germination tests indicated that both Osttl and Ossapk1 mutants significantly reduced seed germination under salt stress compared to the wild type. Haplotype analysis showed that Hap.1 of OsTTL and Hap.1 of OsSAPK1 genes were excellent alleles, and their combination resulted in high seed germination under salt stress. Eight accessions with elite performance of seed germination under salt stress were identified, which could improve rice seed germination under salt stress.

OsHIPL1, a hedgehog-interacting protein-like 1 protein, increases seed vigour in rice.

The cultivation of rice varieties with high seed vigour is vital for the direct seeding of rice, and the molecular basis of regulation of seed vigour remains elusive. Here, we cloned a new gene OsHIPL1, which encodes hedgehog-interacting protein-like 1 protein as a causal gene of the major QTL qSV3 for rice seed vigour. OsHIPL1 was mainly localized in the plasma membrane and nucleus. RNA sequencing (RNA-seq) revealed that the ABA-related genes were involved in the OsHIPL1 regulation of seed vigour in rice. The higher levels of endogenous ABA were measured in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants, with two up-regulated ABA biosynthesis genes (OsZEP and OsNCED4) and one down-regulated ABA catabolism gene OsABA8ox3. The expression of abscisic acid-insensitive 3 (OsABI3), OsABI4 and OsABI5 was significantly up-regulated in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants. These results indicate that the regulation of seed vigour of OsHIPL1 may be through modulating endogenous ABA levels and altering OsABIs expression during seed germination in rice. Meanwhile, we found that OsHIPL1 interacted with the aquaporin OsPIP1;1, then affected water uptake to promote rice seed germination. Based on analysis of single-nucleotide polymorphism data of rice accessions, we identified a Hap1 haplotype of OsHIPL1 that was positively correlated with seed germination. Our findings showed novel insights into the molecular mechanism of OsHIPL1 on seed vigour.

Identification of OsPK5 involved in rice glycolytic metabolism and GA/ABA balance for improving seed germination via genome-wide association study.

Seed germination plays a pivotal role in the plant life cycle, and its precise regulatory mechanisms are not clear. In this study, 19 quantitative trait loci (QTLs) associated with rice seed germination were identified through genome-wide association studies (GWAS) of the following traits in 2016 and 2017: germination rate (GR) at 3, 5, and 7 days after imbibition (DAI) and germination index (GI). Two major stable QTLs, qSG4 and qSG11.1, were found to be associated with GR and GI over 2 continuous years. Furthermore, OsPK5, encoding a pyruvate kinase, was shown to be a crucial regulator of seed germination in rice, and might be a causal gene of the key QTL qSG11.1, on chromosome 11. Natural variation in OsPK5 function altered the activity of pyruvate kinase. The disruption of OsPK5 function resulted in slow germination and seedling growth during seed germination, blocked glycolytic metabolism, caused glucose accumulation, decreased energy levels, and affected the GA/ABA balance. Taken together, our results provide novel insights into the roles of OsPK5 in seed germination, and facilitate its application in rice breeding to improve seed vigour.

Identification and fine mapping of qGR6.2, a novel locus controlling rice seed germination under salt stress.

BACKGROUND: Rice growth is frequently affected by salinity. When exposed to high salinity, rice seed germination and seedling establishment are significantly inhibited. With the promotion of direct-seeding in Asia, improving rice seed germination under salt stress is crucial for breeding. RESULTS: In this study, an indica landrace Wujiaozhan (WJZ) was identified with high germinability under salt stress. A BC1F2 population derived from the crossing WJZ/Nip (japonica, Nipponbare)//Nip, was used to quantitative trait loci (QTL) mapping for the seed germination rate (GR) and germination index (GI) under H2O and 300 mM NaCl conditions. A total of 13 QTLs were identified, i.e. ten QTLs under H2O conditions and nine QTLs under salt conditions. Six QTLs, qGR6.1, qGR8.1, qGR8.2, qGR10.1, qGR10.2 and qGI10.1 were simultaneously identified under two conditions. Under salt conditions, three QTLs, qGR6.2, qGR10.1 and qGR10.2 for GR were identified at different time points during seed germination, which shared the same chromosomal region with qGI6.2, qGI10.1 and qGI10.2 for GI respectively. The qGR6.2 accounted for more than 20% of phenotypic variation under salt stress, as the major effective QTL. Furthermore, qGR6.2 was verified via the BC2F2 population and narrowed to a 65.9-kb region with eleven candidate genes predicted. Based on the microarray database, five candidate genes were found with high transcript abundances at the seed germination stage, of which LOC_Os06g10650 and LOC_Os06g10710 were differentially expressed after seed imbibition. RT-qPCR results showed the expression of LOC_Os06g10650 was significantly up-regulated in two parents with higher levels in WJZ than Nip during seed germination under salt conditions. Taken together, it suggests that LOC_Os06g10650, encoding tyrosine phosphatase family protein, might be the causal candidate gene for qGR6.2. CONCLUSIONS: In this study, we identified 13 QTLs from a landrace WJZ that confer seed germination traits under H2O and salt conditions. A major salt-tolerance-specific QTL qGR6.2 was fine mapped to a 65.9-kb region. Our results provide information on the genetic basis of improving rice seed germination under salt stress by marker-assisted selection (MAS).

ALTERED BRAIN ACTIVITY IN PATIENTS WITH DIABETIC RETINOPATHY USING REGIONAL HOMOGENEITY: A RESTING-STATE fMRI STUDY.

Objective: Previous neuroimaging studies have shown that diabetic retinopathy (DR) is accompanied by abnormal spontaneous brain activity. The purpose of the current study was to investigate changes in brain neural homogeneity in patients with DR using regional homogeneity (ReHo). Methods: A total of 56 subjects were recruited, including 28 patients with DR (16 female and 12 male patients) and 28 healthy controls (HCs) (16 female and 12 male patients) approximately matched for age and sex. All subjects underwent resting-state functional magnetic resonance imaging scans. The ReHo method was applied to explore neural homogeneity in the brain. The patients with DR were distinguished from HCs following the construction of receiver operating characteristic curves. The ReHo method was applied to assess changes in synchronous neural activity. Results: Compared to HCs, the ReHo values in the left and right posterior lobes of the cerebellum in patients with DR were significantly increased, whereas ReHo values in the right anterior cingulate gyrus, right cuneus, bilateral precuneus, and left-middle frontal gyrus were significantly decreased. In addition, the ReHo value in the right cuneus showed a positive correlation with the best corrected visual acuity in patients with DR. Conclusion: Dysfunctional brain homology may reveal the pathological mechanisms underlying the visual pathways of patients with DR. Abbreviations: AUC = area under the curve; BA = Brodmann area; DR = diabetic retinopathy; fMRI = functional magnetic resonance imaging; HC = healthy control; MRI = magnetic resonance imaging; rs-fMRI = resting-state fMRI; ReHo = regional homogeneity; ROC = receiver operating characteristic.

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

OBJECTIVE: The targets of this study were to access the alternations of spontaneous brain activity in RD patients by amplitude of low-frequency fluctuation (ALFF) method and to explore their relationships with clinical behavioral performance. METHODS: A total of 20 patients with RD (6 males and 14 females), and 20 healthy controls (HCs) (6 males and 14 females) were recruited, and were matched in sex and age. All participants finished the functional magnetic resonance imaging (fMRI) scanning. We applied the ALFF method to detect the spontaneous brain activity. Receiver operating characteristic (ROC) curve was applied to distinguish RD Patients from HCs. RESULTS: RD patients showed decreased ALFF values in the right occipital lobe and right medial frontal gyrus and increased ALFF values in the right frontal superior orbital and left inferior temporal gyrus when compared with HCs. In RD patients, we did not find any relationship between the mean ALFF values and the clinical behavioral performances. CONCLUSION: The RD patients exhibited abnormal spontaneous brain activity in vision and vision related brain regions, which might explore potential pathological mechanism of acute vision loss in RD patients.

Altered Spontaneous Brain Activity in Patients with Classical Trigeminal Neuralgia Using Regional Homogeneity: A Resting-State Functional MRI Study.

OBJECTIVE: Neuroimaging studies have shown that patients with pain-related conditions have altered neuronal activity and structural functions. The purpose of this study was to investigate whether patients with classical trigeminal neuralgia (CTN) exhibit changes in corresponding neuronal activity via analysis of neuronal activity regional homogeneity (ReHo). METHODS: A total of 28 patients presenting with sore eyes (12 men and 16 women) were matched with 28 healthy controls (12 men and 16 women). All participants underwent functional magnetic resonance imaging (fMRI). This ReHo method was used to assess the consistency of changes in neural activity in various brain regions. The receiver operating characteristic (ROC) curve was applied to differentiate ReHo values of patients with CTN from ReHo values of healthy controls. Pearson's correlation analysis was applied to evaluate the correlation between ReHo values of different brain regions of patients with CTN and clinical manifestations. RESULTS: Compared with healthy controls, patients with CTN were found to have increased ReHo values in the inferior cerebellum bilaterally, right inferior temporal gyrus, right middle occipital gyrus, right fusiform gyrus, right superior frontal gyrus, and right precentral gyrus. ROC curve analysis of each brain region revealed near-perfect accuracy regarding the area under the curve. However, no correlation between ReHo values and clinical manifestations in patients with CTN was found. CONCLUSIONS: CTN is associated with altered neuronal networks in different areas of the brain. ReHo values all possess different degrees of change, implying that CTN has a certain impact on cerebral function.

Resting cerebral blood flow alterations specific to the comitant exophoria patients revealed by arterial spin labeling perfusion magnetic resonance imaging.

PURPOSE: It has been shown in many previous studies that there were significant changes of the brain anatomy and function in strabismus. However, the significance of the alterations of resting cerebral blood flow (CBF) in comitant exophoria (CE) remains obscure. Arterial spin labeling (ASL) MRI, which is a noninvasive method, could be applied to detect the cerebral blood flow quantitatively. Our study aimed to compare the resting CBF between the comitant exophoria and health controls using pseudo-continuous arterial spin labeling (pCASL) perfusion MRI method. METHODS: 32 patients (25 males and 7 females) with CE (study group), and 32 (25 males and 7 females) healthy individuals with matched age and sex status (control group) underwent a whole-brain pCASL magnetic resonance (MR) examination at the resting state. The resting CBF were voxel-wise compared between the two groups using an analysis of variance designed in a statistical parametric mapping program. The CE patients were distinguishable from the healthy controls (HCs) by receiver operating characteristic (ROC) curves. RESULTS: Compared with the control group, the CE group showed significantly increased resting CBF values in the right parahippocampal regions, bilateral medial frontal gyrus/anterior cingulate cortex, left inferior frontal gyrus, right inferior frontal gyrus, left superior frontal gyrus, bilateral medial cingulate cortex, right middle frontal gyrus, and right paracentral lobule. CONCLUSION: Comitant exophoria showed increased resting CBF in eye movement-related brain areas including supplementary eye field, cingulate eye field and frontal eye field, which could be an explanation of the brain function compensation for the ocular motility disorders in the CE patients.

p-Toluenesulfonic acid enhanced neutral deep eutectic solvent pretreatment of soybean straw for efficient lignin removal and enzymatic hydrolysis.

Deep eutectic solvent (DES) is a newly-emerged green solvent for efficient pretreatment of lignocellulosic feedstock. To improve the component fractionation performance of neutral DES, p-toluenesulfonic acid (p-TsOH) was employed as catalyst to form a novel ternary DES with benzyltriethylammonium chloride (TEBAC) and glycerol (Gly) for pretreatment of soybean straw. Under the optimum reaction conditions (TEBAC:Gly = 1:12, 1.6 wt% p-TsOH and reacted at 90 °C for 160 min), the lignin and hemicellulose removal from soybean straw were amounted to 92.0 % and 88.2 %, respectively. The pretreated substrate showed satisfactory enzymatic hydrolysis performance, as the glucose and reducing sugar concentrations reached 37.3 g/L and 42.3 g/L, respectively, after 72 h saccharification under the action of cellulase with a relatively low enzyme loading of 10 FPU/g cellulose.This method provides an efficient and mild route for utilization of agricultural waste and production of platform monosaccharides.

Allantoate Amidohydrolase OsAAH is Essential for Preharvest Sprouting Resistance in Rice.

Preharvest sprouting (PHS) is an undesirable trait that decreases yield and quality in rice production. Understanding the genes and regulatory mechanisms underlying PHS is of great significance for breeding PHS-resistant rice. In this study, we identified a mutant, preharvest sprouting 39 (phs39), that exhibited an obvious PHS phenotype in the field. MutMap+ analysis and transgenic experiments demonstrated that OsAAH, which encodes allantoate amidohydrolase, is the causal gene of phs39 and is essential for PHS resistance. OsAAH was highly expressed in roots and leaves at the heading stage and gradually increased and then weakly declined in the seed developmental stage. OsAAH protein was localized to the endoplasmic reticulum, with a function of hydrolyzing allantoate in vitro. Disruption of OsAAH increased the levels of ureides (allantoate and allantoin) and activated the tricarboxylic acid (TCA) cycle, and thus increased energy levels in developing seeds. Additionally, the disruption of OsAAH significantly increased asparagine, arginine, and lysine levels, decreased tryptophan levels, and decreased levels of indole-3-acetic acid (IAA) and abscisic acid (ABA). Our findings revealed that the OsAAH of ureide catabolism is involved in the regulation of rice PHS via energy and hormone metabolisms, which will help to facilitate the breeding of rice PHS-resistant varieties.

Gray matter volume alterations in patients with strabismus and amblyopia: voxel-based morphometry study.

This study proposes the use of the voxel-based morphometry (VBM) technique to investigate structural alterations of the cerebral cortex in patients with strabismus and amblyopia (SA). Sixteen patients with SA and sixteen healthy controls (HCs) underwent magnetic resonance imaging. Original whole brain images were analyzed using the VBM method. Pearson correlation analysis was performed to evaluate the relationship between mean gray matter volume (GMV) and clinical manifestations. Receiver operating characteristic (ROC) curve analysis was applied to classify the mean GMV values of the SA group and HCs. Compared with the HCs, GMV values in the SA group showed a significant difference in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, bilateral parahippocampal gyrus, and left anterior cingulate cortex. The mean GMV value in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, and bilateral parahippocampal gyrus were negatively correlated with the angle of strabismus. The ROC curve analysis of each cerebral region confirmed the accuracy of the area under the curve. Patients with SA have reduced GMV values in some brain regions. These findings might help to reveal the potential pathogenesis of SA and its relationship with the atrophy of specific regions of the brain.

Endoscopic tightening of the cardia mucosa in gastroesophageal reflux disease: A case series of 120 patients up to 1-year follow-up.

Background and Aim: A technique of endoscopic tightening of the cardia mucosa for the treatment of gastroesophageal reflux disease (GERD) was developed and its clinical efficacy was observed. Methods: 120 patients with GERD who underwent endoscopic tightening surgery from December 2017 to December 2019 were included in this study. GERD-Q score and constitution type of patients were evaluated preoperatively and at 1 month, 3 months, 6 months, and 1 year after surgery. In addition, effectiveness and side effects of the procedure were graded based on gastroesophageal flap valve (GEFV) function. Results: GERD-Q score of 1 month, 3 months, 6 months, and 1 year after surgery were significantly decreased (P<0.01) compared with preoperative score. There were no significant differences between GERD-Q score of 1 month, 3 months, 6 months, and 1 year after surgery. The surgery proves to be effective in all GEFV grades, especially in Hill-III. Conclusion: Endoscopic tightening is an effective method for the treatment of patients with GERD, especially of Hill-III patients. Attention should be paid to cardia width, ligation ring depth, and ring number during operation. Relevance for Patients: ETCM is a safe endoscopic procedure with minimal trauma, which has been proved effective for patients who are diagnosed with GERD.

Endoscopic tightening of the cardia mucosa in gastroesophageal reflux disease: A case series of 120 patients up to 1-year follow-up.

Background and Aim: A technique of endoscopic tightening of the cardia mucosa for the treatment of gastroesophageal reflux disease (GERD) was developed and its clinical efficacy was observed. Methods: 120 patients with GERD who underwent endoscopic tightening surgery from December 2017 to December 2019 were included in this study. GERD-Q score and constitution type of patients were evaluated preoperatively and at 1 month, 3 months, 6 months, and 1 year after surgery. In addition, effectiveness and side effects of the procedure were graded based on gastroesophageal flap valve (GEFV) function. Results: GERD-Q score of 1 month, 3 months, 6 months, and 1 year after surgery were significantly decreased (P<0.01) compared with preoperative score. There were no significant differences between GERD-Q score of 1 month, 3 months, 6 months, and 1 year after surgery. The surgery proves to be effective in all GEFV grades, especially in Hill-III. Conclusion: Endoscopic tightening is an effective method for the treatment of patients with GERD, especially of Hill-III patients. Attention should be paid to cardia width, ligation ring depth, and ring number during operation. Relevance for Patients: ETCM is a safe endoscopic procedure with minimal trauma, which has been proved effective for patients who are diagnosed with GERD.

PKM2 Is a Potential Diagnostic and Therapeutic Target for Retinitis Pigmentosa.

Retinitis pigmentosa (RP) is a major cause of blindness that is difficult to diagnose and treat. PKM2, a subtype of pyruvate kinase, is strongly associated with oxidative stress and is expressed in photoreceptors. We investigated whether PKM2 reduces photoreceptor cell apoptosis and evaluated possible antiapoptotic mechanisms in RP. We established RP models by exposing 661W cells to blue light and modulated PKM2 activity using a PKM2 inhibitor. We measured the apoptosis rates using calcein-acetoxymethyl ester/propidium iodide double staining and Cell Counting Kit-8, the oxidative stress levels using a reactive oxygen species assay, and the changes in protein expression by western blotting. Photodamage increased PKM2 expression, cellular oxidative stress, and apoptosis of 661W cells. PKM2 inhibition significantly reduced the levels of apoptosis and oxidative stress induced by photodamage. Our data suggest that PKM2 is a potential disease marker and therapeutic target for RP.

Apolipoprotein A1 and Low-Density Lipoprotein as Risk Factors for Intraocular Metastases in Postmenopausal Breast Cancer.

BACKGROUND: The outcomes of patients with postmenopausal breast cancer(PBC) can be improved through the early detection of intraocular metastases(IOMs). In this study, we investigated patients with PBC, and compared those with IOMs with those with non-intraocular metastases(NIOMs) in terms of blood lipid levels, and then differentiated the risk factors associated with IOMs. METHODS: Student's t-test and a chi-square test were used to discriminate between the IOMs and NIOMs groups. After establishing a Poisson regression model to analyze risk factors, we plotted receiver operating characteristic curves(ROC) to assess the quality of risk factors predicting IOMs. RESULTS: The incidence of IOMs in PBC was 1.16%. There was no significant difference in terms of histopathology between the 2 groups. The levels of total cholesterol (TC), apolipoprotein A1(APOA1) and low-density lipoprotein(LDL) in IOMs were significantly lower than in NIOMs groups. Poisson regression suggested that low levels of APOA1 and LDL were risk factors for IOMs (P = 0.002 and P < 0.001, respectively). ROC curve analysis demonstrated that the cut-off values of APOA1 and LDL were 1.025 g/L and 2.415 mmol/L. The highest prediction accuracy for IOMs involved the combination of APOA1 and LDL (AUC = 0.881, P < 0.001). CONCLUSION: Our research demonstrates that low levels of APOA1 and LDL efficiently predict IOMs in PBC as risk factors, and the combination of APOA1 and LDL was more predictive than single factors.