FLOURY ENDOSPERM24, a heat shock protein 101 (HSP101), is required for starch biosynthesis and endosperm development in rice

Endosperm is the main storage organ in cereal grain and determines grain yield and quality. The molecular mechanisms of heat shock proteins in regulating starch biosynthesis and endosperm development remain obscure. Here, we report a rice floury endosperm mutant flo24 that develops abnormal starch grains in the central starchy endosperm cells. Map-based cloning and complementation test showed that FLO24 encodes a heat shock protein HSP101, which is localized in plastids. The mutated protein FLO24T296I dramatically lost its ability to hydrolyze ATP and to rescue the thermotolerance defects of the yeast hsp104 mutant. The flo24 mutant develops more severe floury endosperm when grown under high-temperature conditions than normal conditions. And the FLO24 protein was dramatically induced at high temperature. FLO24 physically interacts with several key enzymes required for starch biosynthesis, including AGPL1, AGPL3 and PHO1. Combined biochemical and genetic evidence suggests that FLO24 acts cooperatively with HSP70cp-2 to regulate starch biosynthesis and endosperm development in rice. Our results reveal that FLO24 acts as an important regulator of endosperm development, which might function in maintaining the activities of enzymes involved in starch biosynthesis in rice.

[Is low-dose anticoagulation a therapeutic option for patients at high risk of bleeding with high-risk pulmonary thromboembolism]

This issue of Chinese Journal of Tuberculosis and Respiratory Diseases published an interesting case illustrating the identification, treatment, and post-treatment management of a high-risk pulmonary thromboembolism (PTE) that occurred during surgery. It was a high-risk case of PTE, but during treatment, the risk stratification changed to medium-high risk. We should dynamically assess risk stratification and develop diagnosis and treatment plans based on changes in the patient's condition. At the same time, there was a high risk of bleeding in this patient. We should try to decrease the risk of bleeding as much as possible, consider all the conditions that can be applied at that time and on a local level, and devise a safe and effective treatment plan. The socio-economic status of patients may have an impact on how the final diagnosis and treatment plan are implemented. We need to communicate fully with patients, consider comprehensively, and prepare contingency plans to ensure patients' life safety to the greatest extent possible.

OsPRMT6a-mediated arginine methylation of OsJAZ1 regulates jasmonate signaling and spikelet development in rice

Although both protein arginine methylation (PRMT) and jasmonate (JA) signaling are crucial for regulating plant development, the relationship between these processes in spikelet development control remains unclear. Here, we utilized CRISPR/Cas9 technology to generate two OsPRMT6a loss-of-function mutants exhibiting various abnormal spikelet structures. Additionally, we found that OsPRMT6a could methylate arginine residues in the JA signal repressors OsJAZ1 and OsJAZ7. Arginine methylation of OsJAZ1 increased the affinity of OsJAZ1 for the JA receptors OsCOI1a and OsCOI1b in the presence of jasmonates (JAs), subsequently promoting the ubiquitination of OsJAZ1 by the SCFOsCOI1a/OsCOI1b complex and degradation via the 26S proteasome. This process ultimately released OsMYC2, a core transcriptional regulator in the JA signaling pathway, to activate or repress JA-responsive genes, thereby maintaining normal plant (spikelet) development. However, in the osprmt6a-1 mutant, reduced arginine methylation of OsJAZ1 impaired the interaction between OsJAZ1 and OsCOI1a/OsCOI1b in the presence of JAs. As a result, OsJAZ1 proteins became more stable, repressing JA responses, thus causing the formation of abnormal spikelet structures. Moreover, we discovered that JA signaling reduced the OsPRMT6a mRNA level in an OsMYC2-dependent manner, thereby establishing a negative feedback loop to balance JA signaling. Furthermore, we found that OsPRMT6a-mediated arginine methylation of OsJAZ1 likely serves as a switch to tune JA signaling to maintain normal spikelet development under harsh environmental conditions such as high temperatures. Thus, our study established a direct molecular link between arginine methylation and the JA signaling pathway.

Rice LIKE EARLY STARVATION1 cooperates with FLOURY ENDOSPERM6 to modulate starch biosynthesis and endosperm development

In cereal grains, starch is synthesized by the concerted actions of multiple enzymes on the surface of starch granules within the amyloplast. However, little is known about how starch-synthesizing enzymes access starch granules, especially for amylopectin biosynthesis. Here, we show that the rice (Oryza sativa) floury endosperm9 (flo9) mutant is defective in amylopectin biosynthesis, leading to grains exhibiting a floury endosperm with a hollow core. Molecular cloning revealed that FLO9 encodes a plant-specific protein homologous to Arabidopsis (Arabidopsis thaliana) LIKE EARLY STARVATION1 (LESV). Unlike Arabidopsis LESV, which is involved in starch metabolism in leaves, OsLESV is required for starch granule initiation in the endosperm. OsLESV can directly bind to starch by its C-terminal tryptophan (Trp)-rich region. Cellular and biochemical evidence suggests that OsLESV interacts with the starch-binding protein FLO6, and loss-of-function mutations of either gene impair ISOAMYLASE1 (ISA1) targeting to starch granules. Genetically, OsLESV acts synergistically with FLO6 to regulate starch biosynthesis and endosperm development. Together, our results identify OsLESV-FLO6 as a non-enzymatic molecular module responsible for ISA1 localization on starch granules, and present a target gene for use in biotechnology to control starch content and composition in rice endosperm.

Emergence of Long-Range Angular Correlations in Low-Multiplicity Proton-Proton Collisions

This Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at sqrt[s]=13  TeV. Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of 1.4<|Δη|<1.8 and a transverse momentum of 1 Collapse

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First Measurement of the |t| Dependence of Incoherent J/ψ Photonuclear Production

The first measurement of the cross section for incoherent photonuclear production of J/ψ vector mesons as a function of the Mandelstam |t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, |y|<0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. This rapidity interval corresponds to a Bjorken-x range (0.3-1.4)×10^{-3}. Cross sections are given in five |t| intervals in the range 0.04<|t|<1  GeV^{2} and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a |t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

OsALKBH9-mediated m6A demethylation regulates tapetal PCD and pollen exine accumulation in rice

The N6-methyladenosine (m6A) mRNA modification is crucial for plant development and stress responses. In rice, the male sterility resulting from the deficiency of OsFIP37, a core component of m6A methyltransferase complex, emphasizes the significant role of m6A in male fertility. m6A is reversible and can be removed by m6A demethylases. However, whether mRNA m6A demethylase regulates male fertility in rice has remained unknown. Here, we identify the mRNA m6A demethylase OsALKBH9 and demonstrate its involvement in male fertility regulation. Knockout of OsALKBH9 causes male sterility, dependent on its m6A demethylation activity. Cytological analysis reveals defective tapetal programmed cell death (PCD) and excessive accumulation of microspores exine in Osalkbh9-1. Transcriptome analysis of anthers shows up-regulation of genes involved in tapetum development, sporopollenin synthesis, and transport pathways in Osalkbh9-1. Additionally, we demonstrate that OsALKBH9 demethylates the m6A modification in TDR and GAMYB transcripts, which affects the stability of these mRNAs and ultimately leads to excessive accumulation of pollen exine. Our findings highlight the precise control of mRNA m6A modification and reveal the pivotal roles played by OsALKBH9-mediated m6A demethylation in tapetal PCD and pollen exine accumulation in rice.

Fine-tuning rice heading date through multiplex editing of the regulatory regions of key genes by CRISPR-Cas9

Heading date (or flowering time) is a key agronomic trait that affects seasonal and regional adaption of rice cultivars. An unoptimized heading date can either not achieve a high yield or has a high risk of encountering abiotic stresses. There is a strong demand on the mild to moderate adjusting the heading date in breeding practice. Genome editing is a promising method which allows more precise and faster changing the heading date of rice. However, direct knock out of major genes involved in regulating heading date will not always achieve a new germplasm with expected heading date. It is still challenging to quantitatively adjust the heading date of elite cultivars with best adaption for broader region. In this study, we used a CRISPR-Cas9 based genome editing strategy called high-efficiency multiplex promoter-targeting (HMP) to generate novel alleles at cis-regulatory regions of three major heading date genes: Hd1, Ghd7 and DTH8. We achieved a series of germplasm with quantitative variations of heading date by editing promoter regions and adjusting the expression levels of these genes. We performed field trials to screen for the best adapted lines for different regions. We successfully expanded an elite cultivar Ningjing8 (NJ8) to a higher latitude region by selecting a line with a mild early heading phenotype that escaped from cold stress and achieved high yield potential. Our study demonstrates that HMP is a powerful tool for quantitatively regulating rice heading date and expanding elite cultivars to broader regions.

Genetic and molecular mechanisms of reproductive isolation in the utilization of heterosis for breeding hybrid rice

Heterosis, also known as hybrid vigor, is commonly observed in rice crosses. The hybridization of rice species or subspecies exhibits robust hybrid vigor, however, the direct harnessing of this vigor is hindered by reproductive isolation. Here, we review recent advances in the understanding of the molecular mechanisms governing reproductive isolation in inter-subspecific and inter-specific hybrids. This review encompasses the genetic model of reproductive isolation within and among Oryza sativa species, emphasizing the essential role of mitochondria in this process. Additionally, we delve into the molecular intricacies governing the interaction between mitochondria and autophagosomes, elucidating their significant contribution to reproductive isolation. Furthermore, our exploration extends to comprehending the evolutionary dynamics of reproductive isolation and speciation in rice. Building on these advances, we offer a forward-looking perspective on how to overcome the challenges of reproductive isolation and facilitate the utilization of heterosis in future hybrid rice breeding endeavors.

[Epidemiological and clinical features of newly reported advanced schistosomiasis cases in Sichuan Province from 2011 to 2022]

OBJECTIVE

To analyze the epidemiological characteristics of newly reported advanced schistosomiasis cases in Sichuan Province, so as to provide the evidence for analyzing the causes and formulating targeted control measures of newly reported advanced schistosomiasis cases.

METHODS

Individual case investigation forms for advanced schistosomiasis cases were collected from the Sichuan Provincial Epidemic Annual Report System from 2011 to 2022, and patients' demographics, previous medical history and liver parenchymal grading were retrieved. All advanced schistosomiasis cases' medical records were reviewed, and the subtypes of schistosomiasis-endemic villages where the cases' household registration were, floating population, survival and death and time of death were collected.

RESULTS

A total of 321 newly reported advanced schistosomiasis cases were found in Sichuan Province from 2011 to 2022, with a male to female ratio of 0.99 to 1. There were 274 cases at ages of over 50 years (85.4%), with the highest proportion seen at ages of 60 to 69 years (87 cases, 27.1%), and splenomegaly was the most common type (180 cases, 56.1%), with no dwarfism type detected. The highest number of cases was reported in 2011 (78 cases), followed by in 2022 (74 cases), and the highest number of cases were reported in Meishan City (199 cases, 62.0%), Dongpo District (131 cases, 40.8%), and hilly subtype areas (136 cases, 42.4%). As of the end of 2022, there were 111 deaths due to advanced schistosomiasis, with the highest number of deaths seen in 2018 (25 deaths), and the highest mortality was seen among patients with the ascites type (41.2%). There were 47 (37.3%), 40 (59.5%) and 4 (23.5%) cases with grade III liver parenchyma among patients with splenomegaly, ascites, and colonic proliferation types, respectively, and there was a significant difference in the grading of III liver parenchyma among three types of patients (H = 12.092, P < 0.05), with more severe liver parenchyma injuries seen among patients with the ascites type than among those with splenomegaly and colonic proliferation type (Z = 24.262 and 44.738, both Padjusted values < 0.05).

CONCLUSIONS

There have been newly reported advanced schistosomiasis cases in Sichuan Province during recent years, and patients with the ascites type should be given a high priority among advanced schistosomiasis cases in Sichuan Province. Intensified clue surveys are needed for early identification and treatment of advanced schistosomiasis cases, so as to increase the survival rate and improve the quality of life.

In vitro and In vivo evidence demonstrating chronic absence of Ref-1 Cysteine 65 impacts Ref-1 folding configuration, redox signaling, proliferation and metastasis in pancreatic cancer

Ref-1/APE1 (Redox Effector/Apurinic Endonuclease 1) is a multifunctional enzyme that serves as a redox factor for several transcription factors (TFs), e.g., NF-kB, HIF-1α, which in an oxidized state fail to bind DNA. Conversion of these TFs to a reduced state serves to regulate various biological responses such as cell growth, inflammation, and cellular metabolism. The redox activity involves a thiol exchange reaction for which Cys65 (C65) serves as the nucleophile. Using CRISPR editing in human pancreatic ductal adenocarcinoma (PDAC) cells, we changed C65 to Ala (C65A) in Ref-1 to evaluate alteration of Ref-1 redox dynamics as well as chronic loss of Ref-1 redox activity on cell signaling pathways, specifically those regulated by NF-kB and HIF-1α. The redox activity of Ref-1 requires partial unfolding to expose C65, which is buried in the folded structure. Labeling of Ref-1 with polyethylene glycol-maleimide (PEGm) provides a readout of reduced Cys residues in Ref-1 and thereby an assessment of partial unfolding in Ref-1. In comparing Ref-1WT vs Ref-1C65A cell lines, we found an altered distribution of oxidized versus reduced states of Ref-1. Accordingly, activation of NF-kB and HIF-1α in Ref-1C65A lines was significantly lower compared to Ref-1WT lines. The bioinformatic data revealed significant downregulation of metabolic pathways including OXPHOS in Ref-1C65A expressing clones compared to Ref-1WT line. Ref-1C65A also demonstrated reduced cell proliferation and use of tricarboxylic acid (TCA) substrates compared to Ref-1WT lines. A subcutaneous as well as PDAC orthotopic in vivo model demonstrated a significant reduction in tumor size, weight, and growth in the Ref-1C65A lines compared to the Ref-1WT lines. Moreover, mice implanted with Ref-1C65A redox deficient cells demonstrate significantly reduced metastatic burden to liver and lung compared to mice implanted with Ref-1 redox proficient cells. These results from the current study provide direct evidence that the chronic absence of Cys65 in Ref-1 results in redox inactivity of the protein in human PDAC cells, and subsequent biological results confirm a critical involvement of Ref-1 redox signaling and tumorigenic phenotype.

[Tracking evaluation on the implementation of Survey of oncomelanid snails (WS/T 563-2017) in Sichuan and Anhui provinces]

To evaluate the implementation of Survey of oncomelanid snails (WS/T 563-2017) in schistosomiasis-endemic foci, two schistosomiasis-endemic counties were selected from two provinces of Sichuan and Anhui. Professional staff working in province-, city-, county- and township-level disease control and prevention institutions, parasitic disease control institutions or medical institutions were recruited, and the understanding, use and implementation of Survey of oncomelanid snails (WS/T 563-2017) were investigated using questionnaires and interviews. The awareness, use, proportion of propagation and implementation and correct rate of answering questions pertaining to Survey of oncomelanid snails (WS/T 563-2017) were analyzed. A total of 270 questionnaires were allocated, and 269 were recovered, including 254 valid questionnaires. The overall awareness of Survey of oncomelanid snails (WS/T 563-2017) was 84.64% (215/254), and propagation and implementation of Survey of oncomelanid snails (WS/T 563-2017) was not performed in 23.28% (17/73) of the survey institutions following implementation of Survey of oncomelanid snails (WS/T 563-2017), with meeting training and allocation of propagation materials as the main type of propagation and implementation. Among 254 respondents, 77.16% (196/254) were familiar with the standard, 66.14% (168/254) understood the conditions for use of the standard during snail surveys, and 96.85% (246/254) had the approach for identifying snails. In addition, there were 41.73% (106/254), 50.78% (129/254) and 7.48% (19/254) of respondents that considered the operability of Survey of oncomelanid snails (WS/T 563-2017) was very good, good and general, respectively. The findings demonstrate that the issue and implementation of Survey of oncomelanid snails (WS/T 563-2017) has filled the gap for the standardization of snail control techniques, and which plays an importang guiding role in the national schistosomiasis control program.

[Risk factors for the occurrence of laryngopharyngeal reflux disease in the aged and the clinical characteristics of patients complicated with pneumonia]

Objective: To investigate the risk factors for the occurrence of laryngopharyngeal reflux disease in the aged, and to analyze the characteristics of patients with pneumonia. Methods: Patients who underwent 24-hour laryngopharyngeal pH monitoring from June 2020 to July 2022 and the positive patients of those who underwent 24-hour esophageal pH monitoring from March 2017 to July 2022 at the Second Medical Center of the PLA General Hospital were enrolled retrospectively. Positive results of 24-hour laryngopharyngeal reflux monitoring were in the laryngopharyngeal reflux group, and the negative results were in the non-laryngopharyngeal reflux group. Patients with pneumonia and simple gastroesophageal reflux disease were in the esophageal reflux pneumonia group, and patients with pneumonia and simple laryngopharyngeal reflux disease were in the laryngopharyngeal reflux pneumonia group. Patients' basic data, co-morbidities, drug use and relevant examination and test results were collected. Multivariate logistic regression analysis was used to analyze the risk factors of laryngopharyngeal reflux disease in the aged and its relationship with pneumonia. Results: A total of 80 patients with 24-hour laryngopharyngeal pH monitoring were enrolled finally, including 34 cases, all male, aged (73±12) years, in the laryngopharyngeal reflux group, and 46 cases [44 males, 2 females, aged (78±11) years] in the non-laryngopharyngeal reflux group. Multivariate logistic regression analysis showed that the risk factors of laryngopharyngeal reflux disease in the aged included age ≤70 years (OR=13.07, 95%CI: 2.53-67.68), body mass index (BMI) (OR=1.37, each additional 1 kg/m2, 95%CI: 1.03-1.83), use of antipsychotic drugs (OR=8.00, 95%CI: 1.40-45.73) and calcium channel blockers (OR=5.27, 95%CI: 1.13-24.53) (all P<0.05). The protective factors of the laryngopharyngeal reflux disease in the aged included antacids (OR=0.19, 95%CI: 0.04-0.90, P=0.035). The incidence of pneumonia was higher in the laryngopharyngeal reflux group compared with the non-laryngopharyngeal reflux group [44.1% (15/34) vs 21.7% (10/46), P=0.033]. The esophageal reflux pneumonia group included 32 cases [31 males and 1 females, aged (84±12) years]. The laryngopharyngeal reflux pneumonia group included 15 cases [ 15 males, aged (79±11) years]. Compared to the patients in the laryngopharyngeal reflux pneumonia group, the patients in the esophageal reflux pneumonia group had a longer course of antibiotics [(27.7±27.0) vs (14.6±13.9) days, P=0.034], a higher frequency of seizure frequency [(4.3±3.0) vs (1.8±1.5) times/year, P<0.001] and a higher maximal body temperature [(38.2±0.9) vs (37.6±1.1) ℃, P=0.037]. Conclusions: The risk factors of laryngopharyngeal reflux disease in the aged included age ≤70 years, higher BMI, use of antipsychotic drugs and calcium channel blockers. The incidence of pneumonia in laryngopharyngeal reflux disease is higher, but the condition of pneumonia is milder.

[Schistosomiasis control in Sichuan Province since the 12th Five - Year Plan period: progress and prospects]

An ambitious goal has been set for elimination of schistosomiasis in all endemic counties (districts) in Sichuan Province by 2023. To achieve this goal, and to continue to consolidate the control achievements, it is necessary to understand the current endemic status of schistosomiasis, identify the challenges and analyze the experiences and lessons from the schistosomiasis control program, and develop targeted control strategies and interventions in the province. This paper reviews the progress of schistosomiasis control in Sichuan Province since the 12th Five-Year Plan period, analyzes the challenges in the schistosomiasis elimination program, and proposes recommendations for future directions and priorities.

Directed evolution rice genes with randomly multiplexed sgRNAs assembly of base editors

CRISPR-based directed evolution is an effective breeding biotechnology to improve agronomic traits in plants. However, its gene diversification is still limited using individual single guide RNA. We described here a multiplexed orthogonal base editor (MoBE), and a randomly multiplexed sgRNAs assembly strategy to maximize gene diversification. MoBE could induce efficiently orthogonal ABE (<36.6%), CBE (<36.0%), and A&CBE (<37.6%) on different targets, while the sgRNA assembling strategy randomized base editing events on various targets. With respective 130 and 84 targets from each strand of the 34th exon of rice acetyl-coenzyme A carboxylase (OsACC), we observed the target-scaffold combination types up to 27 294 in randomly dual and randomly triple sgRNA libraries. We further performed directed evolution of OsACC using MoBE and randomly dual sgRNA libraries in rice, and obtained single or linked mutations of stronger herbicide resistance. These strategies are useful for in situ directed evolution of functional genes and may accelerate trait improvement in rice.

A CYP78As-small grain4-coat protein complex Ⅱ pathway promotes grain size in rice

CYP78A, a cytochrome P450 subfamily that includes rice (Oryza sativa L.) BIG GRAIN2 (BG2, CYP78A13) and Arabidopsis thaliana KLUH (KLU, CYP78A5), generate an unknown mobile growth signal (referred to as a CYP78A-derived signal) that increases grain (seed) size. However, the mechanism by which the CYP78A pathway increases grain size remains elusive. Here, we characterized a rice small grain mutant, small grain4 (smg4), with smaller grains than its wild type due to restricted cell expansion and cell proliferation in spikelet hulls. SMG4 encodes a multidrug and toxic compound extrusion (MATE) transporter. Loss of function of SMG4 causes smaller grains while overexpressing SMG4 results in larger grains. SMG4 is mainly localized to endoplasmic reticulum (ER) exit sites (ERESs) and partially localized to the ER and Golgi. Biochemically, SMG4 interacts with coat protein complex Ⅱ (COPⅡ) components (Sar1, Sec23, and Sec24) and CYP78As (BG2, GRAIN LENGTH 3.2 [GL3.2], and BG2-LIKE 1 [BG2L1]). Genetically, SMG4 acts, at least in part, in a common pathway with Sar1 and CYP78As to regulate grain size. In summary, our findings reveal a CYP78As-SMG4-COPⅡ regulatory pathway for grain size in rice, thus providing new insights into the molecular and genetic regulatory mechanism of grain size.

A toxin-antidote system contributes to interspecific reproductive isolation in rice

Breakdown of reproductive isolation facilitates flow of useful trait genes into crop plants from their wild relatives. Hybrid sterility, a major form of reproductive isolation exists between cultivated rice (Oryza sativa) and wild rice (O. meridionalis, Mer). Here, we report the cloning of qHMS1, a quantitative trait locus controlling hybrid male sterility between these two species. Like qHMS7, another locus we cloned previously, qHMS1 encodes a toxin-antidote system, but differs in the encoded proteins, their evolutionary origin, and action time point during pollen development. In plants heterozygous at qHMS1, ~ 50% of pollens carrying qHMS1-D (an allele from cultivated rice) are selectively killed. In plants heterozygous at both qHMS1 and qHMS7, ~ 75% pollens without co-presence of qHMS1-Mer and qHMS7-D are selectively killed, indicating that the antidotes function in a toxin-dependent manner. Our results indicate that different toxin-antidote systems provide stacked reproductive isolation for maintaining species identity and shed light on breakdown of hybrid male sterility.

The rice peroxisomal receptor PEX5 negatively regulates resistance to rice blast fungus Magnaporthe oryzae

The receptor protein PEX5, an important component of peroxisomes, regulates growth, development, and immunity in yeast and mammals. PEX5 also influences growth and development in plants, but whether it participates in plant immunity has remained unclear. Here, we report that knockdown of OsPEX5 enhances resistance to the rice blast fungus Magnaporthe oryzae. We demonstrate that OsPEX5 interacts with the E3 ubiquitin ligase APIP6, a positive regulator of plant immunity. APIP6 ubiquitinates OsPEX5 in vitro and promotes its degradation in vivo via the 26S proteasome pathway. In addition, OsPEX5 interacts with the aldehyde dehydrogenase OsALDH2B1, which functions in growth-defense trade-offs in rice. OsPEX5 stabilizes OsALDH2B1 to enhance its repression of the defense-related gene OsAOS2. Our study thus uncovers a previously unrecognized hierarchical regulatory mechanism in which an E3 ubiquitin ligase targets a peroxisome receptor protein that negatively regulates immunity in rice by stabilizing an aldehyde dehydrogenase that suppresses defense gene expression.

Dosimetric Predictors of Acute Diarrhea in Locally Advanced Rectal Cancer Patients Treated with Neoadjuvant Chemoradiation with Capecitabine and Irinotecan: A Discovery and Validation Study

PURPOSE/OBJECTIVE(S)

Additional irinotecan can increase the pCR rate from 15% to 30% compared with capecitabine-based neoadjuvant chemoradiotherapy in locally advanced rectal cancer, while more acute diarrhea was induced and predictors of diarrhea have yet to be fully elucidated. In this analysis, we report the incidence of and factors associated with grade 3+ acute diarrhea in LARC patients treated with the CaplriRT regimen in the CinClare trial.

MATERIALS/METHODS

We identified the dosimetric markers with a lasso-Cox risk scoring model tested on CaplriRT group patients in the CinClare trial at our institution from 2015 to 2017 (CinClare, NCT02605265), and then independently validated according to a predefined protocol in patients treated with neoadjuvant chemoradiation with capecitabine and irinotecan from 2019 to 2022 (NCT05688033). Clinical documentation and patient-reported outcomes were reviewed to determine grade 3+ acute diarrhea events.

RESULTS

A total of 116 patients from Cinclare trial treated with CaplriRT regimen were used as a training cohort to obtain dosimetric prediction model and 168 patients were used for independent validation. The majority received 50 Gray (Gy) in 25 fractions with concurrent capecitabine and irinotecan. Median number of concurrent chemotherapy cycles received was 4 (IQR: 3-4). Seventeen (23.6%) patients treated with the CaplriRT regimen in the CinClare trial experienced grade 3+ acute diarrhea. Dosimetric predictors of acute diarrhea included peritoneal space volume receiving 25 Gy or greater (V25Gy). The single multivariate Cox regression, and receiver operating characteristic (ROC) curve analysis showed that the model had good predictive ability (p<0.05). It was also validated using the validation cohort. Patients with peritoneal space V25Gy>950 cm3 were associated with a higher risk of 3+ acute diarrhea compared with those without constraints of V25Gy (p = 0.002).

CONCLUSION

Peritoneal space V25Gy as an important predictor of acute diarrhea during capecitabine and irinotecan neoadjuvant chemoradiation treatment. Peritoneal space V25Gy < 950 cm3 may reduce acute diarrhea toxicity.

The role of a photographic atlas in reducing unanticipated healthcare utilization following circumcision

INTRODUCTION

Circumcision is a common procedure that can evoke caregiver anxiety in the postoperative period due to unfamiliarity with the healing process. To mitigate unnecessary healthcare utilization such as phone calls and unanticipated clinic or emergency department (ED) visits, photographic atlases have been developed to better prepare caregivers for the recovery process. The objective of our study is to further investigate the efficacy of a photographic atlas in its ability to decrease postoperative healthcare utilization using an increased sample size and extended study period compared to previous studies.

MATERIALS AND METHODS

In this study, we compared a prospective intervention cohort of patients undergoing circumcision at our institution who received a photographic atlas during postoperative teaching to a retrospective cohort of patients who had not received it. Our primary outcome was unanticipated healthcare utilization, defined as postoperative telephone calls and unanticipated presentations to the urology clinic or ED.

RESULTS

The retrospective no-atlas cohort included 105 patients, and the prospective intervention atlas cohort included 80 patients. Both groups were similar with respect to age (p = 0.47) and other demographics. There was no statistically significant difference in healthcare utilization between the no-atlas and atlas cohort. Specifically, we identified no difference in the number of phone calls to clinic staff (12 [11.4%] vs. 11 [13.8%], p = 0.64) or unanticipated postoperative clinic or ED visits (2 [1.9%] vs. 4 [5.0%], p = 0.41).

DISCUSSION

The use of a photographic atlas as part of caregiver support for circumcision patients did not demonstrate a statistically significant reduction in either postoperative phone calls or clinic/ED visits. The decrease in absolute number of caregiver phone calls was minimal (12-11), with a small increase in follow-up presentations (2-4). The lack of significant change may be due to the already infrequent occurrence of these events following circumcision, as demonstrated by the no-atlas cohort. Other potential advantages of the atlas, such as improved caregiver confidence and satisfaction, may have been present, but were not measured in this study.

CONCLUSIONS

Adding to the mixed results of previous studies, these findings do not support that photographic atlases decrease unanticipated healthcare utilization in children undergoing a circumcision. However, utilization was found to be low. Additionally, further studies are needed to determine other significant benefits of this form of education, such as improved caregiver confidence and satisfaction.

WEAK SEED DORMANCY 1, an aminotransferase protein, regulates seed dormancy in rice through the GA and ABA pathways

Seed dormancy is a critical trait that enhances plant survival by preventing seed germination at the wrong time or under unsuitable conditions. Lack of seed dormancy in rice can lead to pre-harvest sprouting on mother plants leading to reduced yield and seed quality. Although some genes have been identified, knowledge of regulation of seed dormancy is limited. Here, we characterized a weak seed dormancy mutant named weak seed dormancy 1 (wsd1) that showed a higher seed germination percentage than the wild-type following the harvest ripeness. We cloned the WSD1 encoding an aminotransferase protein using a MutMap approach. WSD1 was stably expressed after imbibition and its protein was localized in the endoplasm reticulum. A widely targeted metabolomics assay and amino acid analysis showed that WSD1 had a role in regulating homeostasis of amino acids. PAC treatment and RNA-seq analysis showed that WSD1 regulates seed dormancy by involvement in the GA biosynthesis pathway. GA1 content and expression of GA biosynthesis-related genes were increased in the wsd1 mutant compared with the wild-type. The wsd1 mutant had reduced sensitivity to ABA. Our overall results indicated that WSD1 regulates seed dormancy by balancing the ABA and GA pathways.

SET Domain Group 703 Regulates Planthopper Resistance by Suppressing the Expression of Defense-Related Genes

Plant defense responses against insect pests are intricately regulated by highly complex regulatory networks. Post-translational modifications (PTMs) of histones modulate the expression of genes involved in various biological processes. However, the role of PTMs in conferring insect resistance remains unclear. Through the screening of a T-DNA insertion activation-tagged mutant collection in rice, we identified the mutant planthopper susceptible 1 (phs1), which exhibits heightened expression of SET domain group 703 (SDG703). This overexpression is associated with increased susceptibility to the small brown planthopper (SBPH), an economically significant insect pest affecting rice crops. SDG703 is constitutively expressed in multiple tissues and shows substantial upregulation in response to SBPH feeding. SDG703 demonstrates the activity of histone H3K9 methyltransferase. Transcriptomic analysis revealed the downregulation of genes involved in effector-triggered immunity (ETI) and pattern-triggered immunity (PTI) in plants overexpressing SDG703. Among the downregulated genes, the overexpression of SDG703 in plants resulted in a higher level of histone H3K9 methylation compared to control plants. Collectively, these findings indicate that SDG703 suppresses the expression of defense-related genes through the promotion of histone methylation, consequently leading to reduced resistance against SBPH. The defense-related genes regulated by histone methylation present valuable targets for developing effective pest management strategies in future studies. Furthermore, our study provides novel insight into the epigenetic regulation involved in plant-insect resistance.

A natural gene drive system confers reproductive isolation in rice

Hybrid sterility restricts the utilization of superior heterosis of indica-japonica inter-subspecific hybrids. In this study, we report the identification of RHS12, a major locus controlling male gamete sterility in indica-japonica hybrid rice. We show that RHS12 consists of two genes (iORF3/DUYAO and iORF4/JIEYAO) that confer preferential transmission of the RHS12-i type male gamete into the progeny, thereby forming a natural gene drive. DUYAO encodes a mitochondrion-targeted protein that interacts with OsCOX11 to trigger cytotoxicity and cell death, whereas JIEYAO encodes a protein that reroutes DUYAO to the autophagosome for degradation via direct physical interaction, thereby detoxifying DUYAO. Evolutionary trajectory analysis reveals that this system likely formed de novo in the AA genome Oryza clade and contributed to reproductive isolation (RI) between different lineages of rice. Our combined results provide mechanistic insights into the genetic basis of RI as well as insights for strategic designs of hybrid rice breeding.

The transcriptional hub SHORT INTERNODES1 integrates hormone signals to orchestrate rice growth and development

Plants have evolved sophisticated mechanisms to coordinate their growth and stress responses via integrating various phytohormone signaling pathways. However, the precise molecular mechanisms orchestrating integration of the phytohormone signaling pathways remain largely obscure. In this study, we found that the rice (Oryza sativa) short internodes1 (shi1) mutant exhibits typical auxin-deficient root development and gravitropic response, brassinosteroid (BR)-deficient plant architecture and grain size as well as enhanced abscisic acid (ABA)-mediated drought tolerance. Additionally, we found that the shi1 mutant is also hyposensitive to auxin and BR treatment but hypersensitive to ABA. Further, we showed that OsSHI1 promotes the biosynthesis of auxin and BR by activating the expression of OsYUCCAs and D11, meanwhile dampens ABA signaling by inducing the expression of OsNAC2, which encodes a repressor of ABA signaling. Furthermore, we demonstrated that 3 classes of transcription factors, AUXIN RESPONSE FACTOR 19 (OsARF19), LEAF AND TILLER ANGLE INCREASED CONTROLLER (LIC), and OsZIP26 and OsZIP86, directly bind to the promoter of OsSHI1 and regulate its expression in response to auxin, BR, and ABA, respectively. Collectively, our results unravel an OsSHI1-centered transcriptional regulatory hub that orchestrates the integration and self-feedback regulation of multiple phytohormone signaling pathways to coordinate plant growth and stress adaptation.

The OsSGS3-tasiRNA-OsARF3 module orchestrates abiotic-biotic stress response trade-off in rice

Recurrent heat stress and pathogen invasion seriously threaten crop production, and abiotic stress often antagonizes biotic stress response against pathogens. However, the molecular mechanisms of trade-offs between thermotolerance and defense remain obscure. Here, we identify a rice thermo-sensitive mutant that displays a defect in floret development under high temperature with a mutation in SUPPRESSOR OF GENE SILENCING 3a (OsSGS3a). OsSGS3a interacts with its homolog OsSGS3b and modulates the biogenesis of trans-acting small interfering RNA (tasiRNA) targeting AUXIN RESPONSE FACTORS (ARFs). We find that OsSGS3a/b positively, while OsARF3a/b and OsARF3la/lb negatively modulate thermotolerance. Moreover, OsSGS3a negatively, while OsARF3a/b and OsARF3la/lb positively regulate disease resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) and the fungal pathogen Magnaporthe oryzae (M. oryzae). Taken together, our study uncovers a previously unknown trade-off mechanism that regulates distinct immunity and thermotolerance through the OsSGS3-tasiRNA-OsARF3 module, highlighting the regulation of abiotic-biotic stress response trade-off in plants.

Differentially Expressed Circulating Long-Noncoding RNAS in Premature Infants with Respiratory Distress Syndrome

Purpose

Recent studies have addressed the association between lung development and long-noncoding RNAs (lncRNAs). But few studies have investigated the role of lncRNAs in neonatal respiratory distress syndrome (RDS). Thus, this study aimed to compare the expression profile of circulating lncRNAs between RDS infants and controls.

Methods

10 RDS infants and 5 controls were enrolled. RDS patients were further divided into mild and severe RDS subgroups. Blood samples were collected for the lncRNA expression profile. Subsequently, differentially expressed lncRNAs were screened out. Bioinformatics analysis was applied to establish a co-expression network of differential lncRNAs and mRNAs, and predict the underlying biological functions.

Results

A total of 135 differentially expressed lncRNAs were identified, including 108 upregulated and 27 downregulated lncRNAs (fold-change>2 and P<0.05) among the three groups (non-RDS, mild RDS and severe RDS groups). Of these lncRNAs, four were selected as showing higher fold changes and validated by qRT-PCR. ENST00000470527.1, ENST00000504497.1, ENST00000417781.5, and ENST00000440408.5 were increased not only in the plasma of total RDS patients but also in the severe RDS subgroup. Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analyses showed that differentially expressed lncRNAs may play important roles in RDS through regulating PI3KAkt, RAS, MAPK, and TGF-β signaling pathways.

Conclusion

The present results found that ENST00000470527.1, ENST00000504497.1, ENST00000417781.5, and ENST00000440408.5 may be invol ved in RDS. This could provide new insight into research of the potential pathophysiological mechanisms of preterm RDS.

Genome-wide association studies identify OsWRKY53 as a key regulator of salt tolerance in rice

Salinity stress progressively reduces plant growth and productivity, while plant has developed complex signaling pathways to confront salt stress. However, only a few genetic variants have been identified to mediate salt tolerance in the major crop rice, and the molecular mechanism remains poorly understood. Here, we identify ten candidate genes associated with salt-tolerance (ST) traits by performing a genome-wide association analysis in rice landraces. We characterize two ST-related genes, encoding transcriptional factor OsWRKY53 and Mitogen-activated protein Kinase Kinase OsMKK10.2, that mediate root Na+ flux and Na+ homeostasis. We further find that OsWRKY53 acts as a negative modulator regulating expression of OsMKK10.2 in promoting ion homeostasis. Furthermore, OsWRKY53 trans-represses OsHKT1;5 (high-affinity K+ transporter 1;5), encoding a sodium transport protein in roots. We show that the OsWRKY53-OsMKK10.2 and OsWRKY53-OsHKT1;5 module coordinate defenses against ionic stress. The results shed light on the regulatory mechanisms underlying plant salt tolerance.

[Clinical features and CT findings of fibrosing mediastinitis associated pulmonary hypertension]

Objective: To investigate the clinical features and CT findings of pulmonary hypertension (PH) in patients with fibrosing mediastinitis (FM). Methods: Thirteen patients with FM diagnosed between September 2015 and June 2022 were studied retrospectively, including patients with PH (FM-PH group) and patients without PH (FM group) confirmed on right heart catheterization. The t test of two independent samples, Mann-Whitney U rank sum and Fisher's test were used to compare the general information, symptoms, laboratory examination, right ventricular and pulmonary artery measurement data and pulmonary artery CT findings between the two groups, respectively. Results: Compared with the 7 FM patients aged 28-79 (60.00±17.69) years, the 6 patients in the FM-PH group, aged from 60 to 82 (68.83±8.35) years, had more peripheral edema, lower percentage of PaO₂, wider inner diameters of pulmonary artery and right ventricle, a higher ratio of right ventricle and left ventricular transverse diameter, faster tricuspid regurgitation velocity and higher estimated systolic pulmonary artery pressure (P<0.05). There were no differences in BNP levels and tricuspid annular plane systolic excursion between groups (P>0.05). Of the 6 patients with PH, 5 had precapillary PH and 1 had mixed PH. Except that the pulmonary vascular resistance in patients of the FM-PH group was significantly higher than that in the FM group (P<0.05), there were no significant differences in cardiac output, mixed venous oxygen saturation and pulmonary capillary wedge pressure between the two groups. CT pulmonary angiography (CTPA) showed pulmonary artery and vein stenosis. Patients in the FM-PH group had more severe stenosis and occlusion of pulmonary artery and pulmonary vein (P<0.05), and more involvement of multiple pulmonary veins (P<0.05). Conclusions: The clinical manifestation of FM complicated with PH is related to the degree of involvement of pulmonary artery, vein and airway. It is recommended that the disease be evaluated in combination with multiple parameters such as clinical manifestations, cardiac ultrasound, right cardiac catheter and CTPA.

The N6-methyladenosine binding proteins YTH03/05/10 coordinately regulate rice plant height

N⁶-methyladenosine (m⁶A) is the most widely distributed and most abundant type of mRNA modification in eukaryotic. It provides a posttranscriptional level regulation of gene expression by regulating pre-mRNA splicing, mRNA degradation, or mRNA translational efficiency etc. The function of m⁶A modification is decoded by binding proteins that can specially bind to m⁶A. YT521-B homology (YTH) family proteins are the most important m⁶A-binding proteins in mammals and Arabidopsis. However, their roles in growth and development remain unknown. Here, we demonstrated that the YTH family proteins YTH03, YTH05 and YTH10 specifically bind to m⁶A-containing RNAs. Knockout of YTH03, YTH05 or YTH10 causes reduced plant height. Further research showed that simultaneously knockout of YTH03, YTH05 and YTH10 shows severe dwarf phenotype, suggesting these three genes regulate rice plant height in a functionally redundant manner. Additional transcriptome study showed that the reduced plant height of the yth03/05/10 triple mutant may be due to the blocked of diterpenoid and brassinolide synthesis pathway. Overall, we demonstrate that YTH03, YTH05 and YTH10 are all the m⁶A readers in rice and redundantly regulate rice plant height through the hormonal related pathway.

A regulatory loop establishes the link between the circadian clock and abscisic acid signaling in rice

There is a close regulatory relationship between the circadian clock and the abscisic acid (ABA) signaling pathway in regulating many developmental processes and stress responses. However, the exact feedback regulation mechanism between them is still poorly understood. Here, we identified the rice (Oryza sativa) clock component PSEUDO-RESPONSE REGULATOR 95 (OsPRR95) as a transcriptional regulator that accelerates seed germination and seedling growth by inhibiting ABA signaling. We also found that OsPRR95 binds to the ABA receptor gene REGULATORY COMPONENTS OF ABA RECEPTORS10 (OsRCAR10) DNA and inhibits its expression. Genetic analysis showed OsRCAR10 acts downstream of OsPRR95 in mediating ABA responses. In addition, the induction of OsPRR95 by ABA partly required a functional OsRCAR10, and the ABA-responsive element-binding factor ABSCISIC ACID INSENSITIVE5 (OsABI5) bound directly to the promoter of OsPRR95 and activated its expression, thus establishing a regulatory feedback loop between OsPRR95, OsRCAR10, and OsABI5. Taken together, our results demonstrated that the OsRCAR10-OsABI5-OsPRR95 feedback loop modulates ABA signaling to fine-tune seed germination and seedling growth, thus establishing the molecular link between ABA signaling and the circadian clock.

Young Leaf White Stripe encodes a P-type PPR protein required for chloroplast development

Pentatricopeptide repeat (PPR) proteins function in post-transcriptional regulation of organellar gene expression. Although several PPR proteins are known to function in chloroplast development in rice (Oryza sativa), the detailed molecular functions of many PPR proteins remain unclear. Here, we characterized a rice young leaf white stripe (ylws) mutant, which has defective chloroplast development during early seedling growth. Map-based cloning revealed that YLWS encodes a novel P-type chloroplast-targeted PPR protein with 11 PPR motifs. Further expression analyses showed that many nuclear- and plastid-encoded genes in the ylws mutant were significantly changed at the RNA and protein levels. The ylws mutant was impaired in chloroplast ribosome biogenesis and chloroplast development under low-temperature conditions. The ylws mutation causes defects in the splicing of atpF, ndhA, rpl2, and rps12, and editing of ndhA, ndhB, and rps14 transcripts. YLWS directly binds to specific sites in the atpF, ndhA, and rpl2 pre-mRNAs. Our results suggest that YLWS participates in chloroplast RNA group II intron splicing and plays an important role in chloroplast development during early leaf development.

[Epidemiological characteristics of a 2019-nCoV outbreak caused by Omicron variant BF.7 in Shenzhen]

Objective: To explore the epidemiological characteristic of a COVID-19 outbreak caused by 2019-nCoV Omicron variant BF.7 and other provinces imported in Shenzhen and analyze transmission chains and characteristics. Methods: Field epidemiological survey was conducted to identify the transmission chain, analyze the generation relationship among the cases. The 2019-nCoV nucleic acid positive samples were used for gene sequencing. Results: From 8 to 23 October, 2022, a total of 196 cases of COVID-19 were reported in Shenzhen, all the cases had epidemiological links. In the cases, 100 were men and 96 were women, with a median of age, M (Q₁, Q₃) was 33(25, 46) years. The outbreak was caused by traverlers initial cases infected with 2019-nCoV who returned to Shenzhen after traveling outside of Guangdong Province.There were four transmission chains, including the transmission in place of residence and neighbourhood, affecting 8 persons, transmission in social activity in the evening on 7 October, affecting 65 persons, transmission in work place on 8 October, affecting 48 persons, and transmission in a building near the work place, affecting 74 persons. The median of the incubation period of the infection, M (Q₁, Q₃) was 1.44 (1.11, 2.17) days. The incubation period of indoor exposure less than that of the outdoor exposure, M (Q₁, Q₃) was 1.38 (1.06, 1.84) and 1.95 (1.22, 2.99) days, respcetively (Wald χ²=10.27, P=0.001). With the increase of case generation, the number and probability of gene mutation increased. In the same transmission chain, the proportion of having 1-3 mutation sites was high in the cases in the first generation. Conclusions: The transmission chains were clear in this epidemic. The incubation period of Omicron variant BF.7 infection was shorter, the transmission speed was faster, and the gene mutation rate was higher. It is necessary to conduct prompt response and strict disease control when epidemic occurs.

Rice FLOURY ENDOSPERM22, encoding a pentatricopeptide repeat protein, is involved in both mitochondrial RNA splicing and editing and is crucial for endosperm development

Most of the reported P-type pentatricopeptide repeat (PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and their underlying mechanism remains largely unknown. Here, we report a rice floury endosperm22 (flo22) mutant with delayed amyloplast development in endosperm cells. Map-based cloning and complementation tests demonstrated that FLO22 encodes a mitochondrion-localized P-type PPR protein. Mutation of FLO22 resulting in defective trans-splicing of mitochondrial nad1 intron 1 and perhaps causing instability of mature transcripts affected assembly and activity of complex Ⅰ, and mitochondrial morphology and function. RNA-seq analysis showed that expression levels of many genes involved in starch and sucrose metabolism were significantly down-regulated in the flo22 mutant compared with the wild type, whereas genes related to oxidative phosphorylation and the tricarboxylic acid cycle were significantly up-regulated. In addition to involvement in splicing as a P-type PPR protein, we found that FLO22 interacted with DYW3, a DYW-type PPR protein, and they may function synergistically in mitochondrial RNA editing. The present work indicated that FLO22 plays an important role in endosperm development and plant growth by participating in nad1 maturation and multi-site editing of mitochondrial messager RNA.

A deleterious Sar1c variant in rice inhibits export of seed storage proteins from the endoplasmic reticulum

We identified a dosage-dependent dominant negative form of Sar1c, which confirms the essential role of COPII system in mediating ER export of storage proteins in rice endosperm. Higher plants accumlate large amounts of seed storage proteins (SSPs). However, mechanisms underlying SSP trafficking are largely unknown, especially the ER-Golgi anterograde process. Here, we showed that a rice glutelin precursor accumulation13 (gpa13) mutant exhibited floury endosperm and overaccumulated glutelin precursors, which phenocopied the reported RNAi-Sar1abc line. Molecular cloning revealed that the gpa13 allele encodes a mutated Sar1c (mSar1c) with a deletion of two conserved amino acids Pro134 and Try135. Knockdown or knockout of Sar1c alone caused no obvious phenotype, while overexpression of mSar1c resulted in seedling lethality similar to the gpa13 mutant. Transient expression experiment in tobacco combined with subcellular fractionation experiment in gpa13 demonstrated that the expression of mSar1c affects the subcellular distribution of all Sar1 isoforms and Sec23c. In addition, mSar1c failed to interact with COPII component Sec23. Conversely, mSar1c competed with Sar1a/b/d to interact with guanine nucleotide exchange factor Sec12. Together, we identified a dosage-dependent dominant negative form of Sar1c, which confirms the essential role of COPII system in mediating ER export of storage proteins in rice endosperm.

ESCRT-III component OsSNF7.2 modulates leaf rolling by trafficking and endosomal degradation of auxin biosynthetic enzyme OsYUC8 in rice

The endosomal sorting complex required for transport (ESCRT) is highly conserved in eukaryotic cells and plays an essential role in the biogenesis of multivesicular bodies and cargo degradation to the plant vacuole or lysosomes. Although ESCRT components affect a variety of plant growth and development processes, their impact on leaf development is rarely reported. Here, we found that OsSNF7.2, an ESCRT-III component, controls leaf rolling in rice (Oryza sativa). The Ossnf7.2 mutant rolled leaf 17 (rl17) has adaxially rolled leaves due to the decreased number and size of the bulliform cells. OsSNF7.2 is expressed ubiquitously in all tissues, and its protein is localized in the endosomal compartments. OsSNF7.2 homologs, including OsSNF7, OsSNF7.3, and OsSNF7.4, can physically interact with OsSNF7.2, but their single mutation did not result in leaf rolling. Other ESCRT complex subunits, namely OsVPS20, OsVPS24, and OsBRO1, also interact with OsSNF7.2. Further assays revealed that OsSNF7.2 interacts with OsYUC8 and aids its vacuolar degradation. Both Osyuc8 and rl17 Osyuc8 showed rolled leaves, indicating that OsYUC8 and OsSNF7.2 function in the same pathway, conferring leaf development. This study reveals a new biological function for the ESCRT-III components, and provides new insights into the molecular mechanisms underlying leaf rolling.

Isolation and Characterization of SPOTTED LEAF42 Encoding a Porphobilinogen Deaminase in Rice

The formation and development of chloroplasts play a vital role in the breeding of high-yield rice (Oryza sativa L.). Porphobilinogen deaminases (PBGDs) act in the early stage of chlorophyll and heme biosynthesis. However, the role of PBGDs in chloroplast development and chlorophyll production remains elusive in rice. Here, we identified the spotted leaf 42 (spl42) mutant, which exhibited a reddish-brown spotted leaf phenotype. The mutant showed a significantly lower chlorophyll content, abnormal thylakoid morphology, and elevated activities of reactive oxygen species (ROS)-scavenging enzymes. Consistently, multiple genes related to chloroplast development and chlorophyll biosynthesis were significantly down-regulated, whereas many genes involved in leaf senescence, ROS production, and defense responses were upregulated in the spl42 mutant. Map-based cloning revealed that SPL42 encodes a PBGD. A C-to-T base substitution occurred in spl42, resulting in an amino acid change and significantly reduced PBGD enzyme activity. SPL42 targets to the chloroplast and interacts with the multiple organelle RNA editing factors (MORFs) OsMORF8-1 and OsMORF8-2 to affect RNA editing. The identification and characterization of spl42 helps in elucidating the molecular mechanisms associated with chlorophyll synthesis and RNA editing in rice.

Tetrapyrrole biosynthesis pathway regulates plastid-to-nucleus signaling by controlling plastid gene expression in plants

Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants. Previous studies have established that tetrapyrrole biosynthesis (TPB) and plastid gene expression (PGE) play essential roles in plastid retrograde signaling during early chloroplast biogenesis; however, their functional relationship remains unknown. In this study, we generated a series of rice TPB-related gun (genome uncoupled) mutants and systematically analyzed their effects on nuclear and plastid gene expression under normal conditions or when subjected to treatments with norflurazon (NF; a noncompetitive inhibitor of carotenoid biosynthesis) and/or lincomycin (Lin; a specific inhibitor of plastid translation). We show that under NF treatment, expression of plastid-encoded polymerase (PEP)-transcribed genes is significantly reduced in the wild type but is derepressed in the TPB-related gun mutants. We further demonstrate that the derepressed expression of PEP-transcribed genes may be caused by increased expression of the PEP core subunit and nuclear-encoded sigma factors and by elevated copy numbers of plastid genome per haploid genome. In addition, we show that expression of photosynthesis-associated nuclear genes (PhANGs) and PEP-transcribed genes is correlated in the rice TPB-related gun mutants, with or without NF or Lin treatment. A similar correlation between PhANGs and PGE is also observed in the Arabidopsis gun4 and gun5 mutants. Moreover, we show that increased expression of PEP-transcribed plastid genes is necessary for the gun phenotype in NF-treated TPB-related gun mutants. Further, we provide evidence that these TPB-related GUN genes act upstream of GUN1 in the regulation of retrograde signaling. Taken together, our results suggest that the TPB-related GUN genes control retrograde plastid signaling by regulating the PGE-dependent retrograde signaling pathway.

Fructose-6-phosphate-2-kinase/fructose-2,6-bisphosphatase regulates energy metabolism and synthesis of storage products in developing rice endosperm

Starch accounts for about 80-85 % of the dry weight of grains and determines yield by impact on grain weight. And, the content and composition of starch also determine appearance, eating, cooking and nutritional quality of rice. By coordinating crucial reactions of the primary carbohydrate metabolism in all eukaryotes, fructose-2,6-bisphosphate (Fru-2,6-P₂) is a traffic signal in metabolism. However, the metabolic regulation of starch in plant sink tissues by Fru-2,6-P₂ remains unclear. Here we isolated rice mutant floury endosperm23 (flo23) which has opaque endosperm and anomalous compound starch grains (SGs). flo23 mutant grains had reduced contents of starch, lipids and proteins. Map-based cloning and genetic complementation experiments showed that FLO23 encodes a cytoplasmic Fructose-6-phosphate-2-kinase/Fructose-2,6-bisphosphatase (F2KP). Mutation of OsF2KP2 decreased Fru-2,6-P₂ content in endosperm cells, leading to drastically reduced phosphoenolpyruvate (PEP) and pyruvate contents and disordered glycolysis and energy metabolism. The results imply that OsF2KP2 participates in the glycolytic pathway by providing precursors and energy for synthesis of grain storage compounds.

OsPHS1 is required for both male and female gamete development in rice

Meiosis plays an essential role in the production of male and female gametes. Extensive studies have elucidated that homologous chromosome association and pairing are essential for crossing-over and recombination of chromosomal segments. However, the molecular mechanism of chromosome recognition and pairing remains elusive. Here, we identified a rice male-female sterility mutant plant. Cytological observations showed that the development of both pollen and embryo sacs of the mutant were abnormal due to defects in homologous chromosome recognition and pairing during prophase I. Map-based cloning revealed that Os06g0473000 encoding a poor homologous synapsis 1 (PHS1) protein is the candidate target gene, which was confirmed by knockout using CRISPR/Cas9 technology. Sequence analysis revealed a single base mutation (G > A) involving the junction of the fourth exon and intron of OsPHS1, which is predicted to alter splicing, resulting in an Osphs1 mutant. Expression pattern analysis indicated that OsPHS1 expression levels were mainly expressed in panicles at the beginning of meiosis. Subcellular localization analysis demonstrated that the OsPHS1 protein is situated in the nucleus and cytoplasm. Taken together, our results suggest an important role for OsPHS1 in homologous chromosome pairing in both male and female gametogenesis in rice.

[A study on the burden of myocarditis in China in 1990 and 2019]

Objective: To investigate Chinese myocarditis burden and trends in 1990 and 2019. Methods: Based on the Global Burden of Disease (GBD) 2019 data, the number of patients, the number of new cases, the number of deaths, the disability-adjusted life years (DALYs), as well as the morbidity, mortality, DALYs rate and their age-standardized rates were used to analyze the trend and the burden of myocarditis in the Chinese population in 1990 and 2019. Results: In 2019, the number of patients, the number of new cases and the number of deaths with myocarditis in China were 234 900, 275 100 and 13 100 respectively, increasing by 85.62%, 47.51% and 50.22% compared with 1990. The age-standardized incidence and mortality were 16.94/100 000 and 0.92/100 000, respectively. Compared with 1990, the age-standardized incidence in 2019 decreased by 6.06%, and the mortality decreased by 16.04% respectively. The age-standardized incidence and mortality of Chinese male patients with myocarditis were higher than that of female. Compared with 1990, the age group with the largest incidence and mortality of myocarditis in China in 2019 all shifted to the elder group. And, DALYs and age-normalized DALYs due to myocarditis in China showed a decreasing trend in 2019, from 458 600 and 42.51/100 000 in 1990 to 341 300 and 25.39/100 000 in 2019, respectively. The rate of DALYs and age-standardized DALYs in male patients was always higher than female. Conclusions: Compared with 1990, the overall burden of myocarditis in China showed a downward trend in 2019, and the burden of myocarditis in male patients was higher than female. More attention should be paid to the burden of myocarditis in Chinese elderly population.

Ribonuclease H-like gene SMALL GRAIN2 regulates grain size in rice through brassinosteroid signaling pathway

Grain size is a key agronomic trait that determines the yield in plants. Regulation of grain size by brassinosteroids (BRs) in rice has been widely reported. However, the relationship between the BR signaling pathway and grain size still requires further study. Here, we isolated a rice mutant, named small grain2 (sg2), which displayed smaller grain and a semi-dwarf phenotype. The decreased grain size was caused by repressed cell expansion in spikelet hulls of the sg2 mutant. Using map-based cloning combined with a MutMap approach, we cloned SG2, which encodes a plant-specific protein with a ribonuclease H-like domain. SG2 is a positive regulator downstream of GLYCOGEN SYNTHASE KINASE2 (GSK2) in response to BR signaling, and its mutation causes insensitivity to exogenous BR treatment. Genetical and biochemical analysis showed that GSK2 interacts with and phosphorylates SG2. We further found that BRs enhance the accumulation of SG2 in the nucleus, and subcellular distribution of SG2 is regulated by GSK2 kinase activity. In addition, Oryza sativa OVATE family protein 19 (OsOFP19), a negative regulator of grain shape, interacts with SG2 and plays an antagonistic role with SG2 in controlling gene expression and grain size. Our results indicated that SG2 is a new component of GSK2-related BR signaling response and regulates grain size by interacting with OsOFP19.

Improving pre-harvest sprouting resistance in rice by editing OsABA8ox using CRISPR/Cas9

Knock out OsABA8ox helps improve pre-harvest spouting resistance and do not affect rice yield. Pre-harvest sprouting(PHS) is a phenomenon that the seeds of crops germinate preharvest, which reduces the yield and quality of rice. Abscisic acid(ABA) is one of the phytohormones that promotes seed dormancy. ABA8' hydroxylase is the main enzyme that can catabolism ABA in plant. There are three genes that encode ABA8' hydroxylase in rice, named OsABA8ox1, OsABA8ox2 and OsABA8ox3. In this study, we use CRISPR/Cas9 gene editing technology to target these three genes in Ningjing6 and find that the knockout transgenic lines are all significantly strengthen in seed dormancy and have no effect on the yield. By a series of quantitative experiments, we consider that after knock out OsABA8ox, the high endogenous ABA level will influence the ABA signal which suppress the substantial and energy metabolism in the seeds, and finally led to higher dormancy.

OsTUB1 confers salt insensitivity by interacting with Kinesin13A to stabilize microtubules and ion transporters in rice

Salt stress is one of the major environmental factors limiting plant growth and development. Although microtubule (MT) organization is known to be involved in response to salt stress, few tubulin genes have been identified that confer salt insensitivity in plants. In this study, we identified a MT encoding gene, OsTUB1, that increased the survival rate of rice plants under salt stress by stabilizing MT organization and ion transporters. We found that OsTUB1 interacted with Kinesin13A protein, which was essential for OsTUB1-regulated MT organization under salt stress. Further molecular evidence revealed that a OsTUB1-Kinesin13A complex protected rice from salt stress by sustaining membrane-localized Na⁺ transporter OsHKT1;5, a key regulator of ionic homeostasis. Our results shed light on the function of tubulin and kinesin in regulating MT organization and stabilizing Na⁺ transporters and Na⁺ flux at the plasma membrane in rice. The identification of the OsTUB1-Kinesin13A complex provides novel genes for salt insensitivity rice breeding in areas with high soil salinity.

Dwarf and High Tillering1 represses rice tillering through mediating the splicing of D14 pre-mRNA

Strigolactones (SLs) constitute a class of plant hormones that regulate many aspects of plant development, including repressing tillering in rice (Oryza sativa). However, how SL pathways are regulated is still poorly understood. Here, we describe a rice mutant dwarf and high tillering1 (dht1), which exhibits pleiotropic phenotypes (such as dwarfism and increased tiller numbers) similar to those of mutants defective in SL signaling. We show that DHT1 encodes a monocotyledon-specific hnRNP-like protein that acts as a previously unrecognized intron splicing factor for many precursor mRNAs (pre-mRNAs), including for the SL receptor gene D14. We find that the dht1 (DHT1I232F) mutant protein is impaired in its stability and RNA binding activity, causing defective splicing of D14 pre-mRNA and reduced D14 expression, and consequently leading to the SL signaling-defective phenotypes. Overall, our findings deepen our understanding of the functional diversification of hnRNP-like proteins and establish a connection between posttranscriptional splicing and SL signaling in the regulation of plant development.