Evidence for evolution and selection of drought-resistant genes based on high-throughput resequencing in weedy rice.

Weedy rice (Oryza sativa f. spontanea) is a relative of cultivated rice that propagates in paddy fields and has strong drought resistance. In this study, we used 501 rice accessions to reveal the selection mechanism of drought resistance in weedy rice through a combination of selection analysis, genome-wide association studies, gene knockout and overexpression analysis, and Ca2+ and K+ ion flux assays. The results showed that the weedy rice species investigated have gene introgression with cultivated rice, which is consistent with the hypothesis that weedy rice originated from de-domestication of cultivated rice. Regions related to tolerance have particularly diversified during de-domestication and three drought-tolerance genes were identified. Of these, Os01g0800500 was also identified using an assay of the degree of leaf withering under drought, and it was named as PAPH1, encoding a PAP family protein. The drought-resistance capacity of PAPH1-knockout lines was much lower than that of the wild type, while that of overexpression lines was much higher. Concentrations of Ca2+ and K+ were lower in the knockout lines and higher in the overexpression lines compared with those of the wild type, suggesting that PAPH1 plays important roles in coping with drought stress. Our study therefore provides new insights into the genetic mechanisms underlying adaptive tolerance to drought in wild rice and highlights potential new resistance genes for future breeding programs in cultivated rice.

SET DOMAIN GROUP 721 protein functions in saline-alkaline stress tolerance in the model rice variety Kitaake.

To isolate the genetic locus responsible for saline-alkaline stress tolerance, we developed a high-throughput activation tagging-based T-DNA insertion mutagenesis method using the model rice (Oryza sativa L.) variety Kitaake. One of the activation-tagged insertion lines, activation tagging 7 (AC7), showed increased tolerance to saline-alkaline stress. This phenotype resulted from the overexpression of a gene that encodes a SET DOMAIN GROUP 721 protein with H3K4 methyltransferase activity. Transgenic plants overexpressing OsSDG721 showed saline-alkaline stress-tolerant phenotypes, along with increased leaf angle, advanced heading and ripening dates. By contrast, ossdg721 loss-of-function mutants showed increased sensitivity to saline-alkaline stress characterized by decreased survival rates and reduction in plant height, grain size, grain weight and leaf angle. RNA sequencing (RNA-seq) analysis of wild-type Kitaake and ossdg721 mutants indicated that OsSDG721 positively regulates the expression level of HIGH-AFFINITY POTASSIUM (K+ ) TRANSPORTER1;5 (OsHKT1;5), which encodes a Na+ -selective transporter that maintains K+ /Na+ homeostasis under salt stress. Furthermore, we showed that OsSDG721 binds to and deposits the H3K4me3 mark in the promoter and coding region of OsHKT1;5, thereby upregulating OsHKT1;5 expression under saline-alkaline stress. Overall, by generating Kitaake activation-tagging pools, we established that the H3K4 methyltransferase OsSDG721 enhances saline-alkaline stress tolerance in rice.

Effectiveness of tigecycline in the treatment of infections caused by carbapenem-resistant gram-negative bacteria in pediatric liver transplant recipients: A retrospective study.

INTRODUCTION: Tigecycline (TGC) is effective for the infections caused by carbapenem-resistant gram-negative bacteria (CRGNB) in adults, but it is not investigated systematically in children because of concern about adverse effects. This study aimed to analyze the effectiveness of TGC in treating CRGNB infections in children after receiving liver transplant. METHODS: The subjects in this retrospective study were pediatric liver transplant recipients treated with TGC for at least 3 days to fight microbiologically verified CRGNB infection after initial antibiotic failure during the period from January 2014 to May 2018. Clinical and microbiological outcomes were reviewed to evaluate the efficacy and safety of TGC. RESULTS: Of the 1177 pediatric liver transplant recipients, 13 patients were eligible for inclusion in this analysis. All the patients received TGC at dose of 2 mg/kg every 12 hours for a duration of 10.1 ± 5.1 days on average to treat CRGNB infections, including complicated intra-abdominal infection, ventilator-associated pneumonia, and bloodstream infection. The isolates included Klebsiella pneumoniae (69.2%, 9/13) and Acinetobacter baumannii (30.8%, 4/13). Clinical efficacy was achieved in 84.6% (11/13) and pathogen eradicated in 69.2% (9/13) of the patients. The overall mortality rate was 15.4% (2/13). No TGC-related serious adverse event was reported. CONCLUSION: Tigecycline can be considered in combination antimicrobial regimen for treating CRGNB-related infections in pediatric liver transplant recipients.

The Effects of Liver Transplantation in Children With Niemann-Pick Disease Type B.

We evaluated the effects of liver transplantation (LT) in children with Niemann-Pick disease (NPD) type B. From October 2006 to October 2018, 7 of 1512 children who received LT at Ren Ji Hospital were diagnosed as NPD type B. The median age at diagnosis was 12 months (6-14 months) with initial presentations of hepatosplenomegaly, growth retardation, repeated pneumonia, and diarrhea. Even after comprehensive supporting treatments, all patients developed liver dysfunction, severe interstitial pulmonary disease, compromised lung function, and hypersplenism, with hypertriglyceridemia in 4 patients. They were transferred to our hospital for transplantation (median age, 6.5 years; range, 2.2-8.6 years). Among them, 4 patients received living donor LT, and 3 received whole-liver orthotopic LT. Splenectomy was conducted spontaneously. All patients are alive with a median follow-up of 10 months (range, 5-53 months). Liver function normalized within 3 weeks after transplantation and maintained stability. Thrombocytopenia and leukopenia were cured, as was hypertriglyceridemia. Strikingly, pulmonary disease was relieved after transplantation, as evidenced by resolution of interstitial lung disease and restored lung function. Bronchitis occurred only once among the 3 patients with a quick recovery during follow-up. Catch-up growth was observed in all patients, especially in 1 male patient, as his height z score increased from -3.9 to -1 at 4 years after transplantation. Patients with follow-up longer than 10 months indicated significant psychomotor ability improvement. Hypotonia was relieved in 4 patients after transplantation. However, intelligence developmental delay still existed in 4 patients during the follow-up. Three of them have been receiving intelligence recovery therapy, although the longterm effect needs more investigation. In conclusion, LT is a safe and effective treatment for patients with NPD type B with severe liver and pulmonary dysfunction.

FLA, which encodes a homolog of UBP, is required for chlorophyll accumulation and development of lemma and palea in rice.

KEY MESSAGE: FLA, the homolog of ubiquitin-specific protease does not have deubiquitination activity, but it is essential for flower and chloroplast development in rice. Ubiquitin-specific proteases (UBPs) are widely distributed and highly conserved proteins and are also members of the most important family of deubiquitination enzymes. Although the functions and phylogenies of UBPs from yeast, mammals and Arabidopsis have been widely reported, the functions and evolutionary relationships of UBPs in rice remain unclear. In this study, we characterized the rice flower and leaf color aberrant mutant (fla), which exhibited a variety of developmental defects, including abnormal floral organs and pollen development, and leaf bleaching. We isolated FLA by positional cloning and found that it encodes a homolog of ubiquitin-specific protease. FLA is a ubiquitously expressed gene with the highest expression in floral organs. Subcellular localization analysis indicated that FLA is a cell membrane protein. Through searches of the rice genome database ( http://rice.plantbiology.msu.edu ), we identified 35 UBP family members in the rice genome. These proteins were grouped into 16 subfamilies based on phylogenetic analysis, and FLA was found to belong to the G8 subfamily. In vitro activity assays revealed that FLA does not have deubiquitination activity. Our data suggest that FLA plays an important role in the development of floral organs and chloroplast in rice, but that this role probably does not involve deubiquitination activity, because FLA does not have an active site and deubiquitination activity.

Risk stratification system to predict recurrence of intrahepatic cholangiocarcinoma after hepatic resection.

BACKGROUND: Previous nomograms for intrahepatic cholangiocarcinoma (ICC) were conducted to predict overall survival, which could be influenced by various factors. Herein, we conducted our nomogram to predict recurrence of the tumor only after hepatic resection. METHODS: The nomogram was established with prognostic factors for the relapse-free survival (RFS) analyzed from our single center cohort and was evaluated by comparing with the American Joint Committee on Cancer (AJCC) staging system for the predictive accuracy. RESULTS: Seropositivity of hepatitis B surface antigen (hazard ratio [HR], 0.505; 95% confidence interval [CI], 0.279 to 0.914; P = 0.024), tumor size of larger than 5 cm (HR, 1.947; 95% CI, 1.177 to 3.219; P = 0.009), Child-Pugh score of B (HR, 3.067; 95% CI, 1.293 to 7.275; P = 0.011), and lymph node metastasis (HR, 2.790; 95% CI, 1.628 to 4.781; P < 0.001) were found to be independent prognostic factors that significantly affected RFS. The calibration curve for the prediction revealed excellent agreement between estimation by our stratification system and actual RFS. The concordance C index of the nomogram (0.71; 95% CI, 0.65 to 0.77) revealed to be significantly higher than the AJCC staging system (0.66; 95% CI, 0.60 to 0.72). In the validation cohort, our risk stratification system (C-index 0.65; 95% CI, 0.59 to 0.71) also revealed more precise prediction than the AJCC staging system (C-index, 0.57; 95% CI, 0.50 to 0.64). CONCLUSIONS: Our nomogram could more accurately predict recurrence of ICC after hepatic resection than the AJCC staging system.

Diagnosis and outcomes of collateral arterial formation after irreversible early hepatic artery thrombosis in pediatric liver recipients.

BACKGROUND: Early hepatic artery thrombosis (eHAT) has been recognized as an important cause of graft loss and mortality. However, the incidence, etiology and outcome are not clear, especially for children. The present study was to investigate the formation of collateral artery flow after irreversible eHAT and its impact on patient's prognosis. METHODS: We analyzed eHAT after liver transplantation in children from October 2006 to April 2015 in our center, illustrated the formation of collateral hepatic artery flow after irreversible eHAT and explored the diagnosis, complications, treatment and prognosis. The basic and follow-up ultrasonographic images were also compared. RESULTS: Of the 330 pediatric liver recipients, 22 (6.67%) developed eHAT within 1 month. Revascularization attempts including surgical thrombectomy, interventional radiology and conservational treatment (thrombolysis) were successful in 5 patients. Among the 17 patients who had irreversible eHAT, follow-up ultrasonography revealed that collateral artery flow was developed as early as 2 weeks after eHAT. Liver abscess and bile duct complication occurred secondary to eHAT in variable time. CONCLUSIONS: Collateral arterial formation is a compensatory adaptation to eHAT to supply blood to liver grafts. However, the severe bile duct damage secondary to eHAT is irreversible and retransplantation is unavoidable.

The wheat MYB transcription factor TaMYB18 regulates leaf rolling in rice.

Leaf rolling is an important agronomic trait in crop breeding. Moderate leaf rolling maintains the erectness of leaves and minimizes shadowing between leaves, leading to improved photosynthetic efficiency. Although some genes controlling leaf rolling have been isolated from rice and other plant species, few studies have examined leaf rolling in wheat. In the present study, the leaf rolling regulator gene, TaMYB18, was identified in a large-scale transgene project involving the transformation of 1455 wheat transcription factor genes into rice. Three homologous sequences of TaMYB18 were isolated from hexaploid wheat and localized to chromosomes 5A, 5B and 5D, respectively. TaMYB18, an R2R3-MYB transcription factor, localized to the nucleus. TaMYB18 overexpression induced leaf rolling in transgenic rice. Additionally, the three members of TaMYB18 exhibited functional redundancy in rice. Furthermore, the function of TaMYB18 in regulating leaf rolling in rice was a dose-dependent. Taken together, these results indicate that TaMYB18 may play an important role in the regulation of leaf development.

Diachronic analysis of genetic diversity in rice landraces under on-farm conservation in Yunnan, China.

KEY MESSAGE: Diachronic analysis showed no significant changes in the level of genetic diversity occurred over the past 27 years' domestication, which indicated genetic diversity was successfully maintained under on-farm conservation. Rice (Oryza sativa L.) is one of the earliest domesticated crop species. Its genetic diversity has been declining as a result of natural and artificial selection. In this study, we performed the first analysis of the levels and patterns of nucleotide variation in rice genomes under on-farm conservation in Yunnan during a 27-year period of domestication. We performed large-scale sequencing of 600 rice accessions with high diversity, which were collected in 1980 and 2007, using ten unlinked nuclear loci. Diachronic analysis showed no significant changes in the level of genetic diversity occurring over the past 27 years' domestication, which indicated genetic diversity was successfully maintained under on-farm conservation. Population structure revealed that the rice landraces could be grouped into two subpopulations, namely the indica and japonica groups. Interestingly, the alternate distribution of indica and japonica rice landraces could be found in each ecological zone. The results of AMOVA showed that on-farm conservation provides opportunities for continued differentiation and variation of landraces. Therefore, dynamic conservation measures such as on-farm conservation (which is a backup, complementary strategy to ex situ conservation) should be encouraged and enhanced, especially in crop genetic diversity centers. The results of this study offered accurate insights into short-term evolutionary processes and provided a scientific basis for on-farm management practices.

Liver transplantation for biliary atresia: A nationwide investigation from 1996 to 2013 in mainland China.

We investigated the overall situation of LT for BA in mainland China and analyzed their survival outcomes based on data from CLTR. Between January 1996 and December 2013, 509 liver transplants for BA were performed in mainland China and were included in this study. Patients' median age was 9.6 months (range: 4.8-175.2 months). KP was previously performed in 194 cases (38.1%). Grafts from living donors were used in 380 cases (74.7%). Era I (1996.1-2010.12) and era II (2011.1-2013.12) comprised 151 cases (29.7%) and 358 cases (70.3%), respectively. Twenty-five centers had performed at least one liver transplant for children with BA. Centers from Shanghai (197 cases), Tianjin (143 cases) and Beijing (81 cases) involved 82.7% of the 509 cases. One- and five-yr graft survival rates were 84.7% and 72.6%, respectively. Split grafts, center volume <20, GRWR ≥4.0%, and steroid-free immunosuppression regimen were independent risk factors for graft survival. In conclusion, the dramatic expansion of pediatric liver transplant programs in mainland China has enabled improved survival for those children affected by this devastating disease. However, screening of BA in neonates should be emphasized throughout the country to enhance early referrals for KP.

The wheat MYB-related transcription factor TaMYB72 promotes flowering in rice.

Through large-scale transformation analyses, TaMYB72 was identified as a flowering time regulator in wheat. TaMYB72 is a MYB family transcription factor localized to the nucleus. Three TaMYB72 homologs, TaMYB72-A, TaMYB72-B and TaMYB72-D, cloned from hexaploid wheat were mapped to the short arm of the group 6 chromosomes. Under the long-day conditions, over-expression of the TaMYB72 in rice shortened the flowering time by approximately 12 d. Expression analyses suggest that TaMYB72 may function through up-regulation of florigen genes Hd3a and RFT1.

Impact of hepatic arterial hemodynamics in predicting early hepatic arterial thrombosis in pediatric recipients younger than three yr after living donor liver transplantation.

We used Doppler US to evaluate the changes in hepatic arterial hemodynamics that occur following LDLT in pediatric recipients, with a view to assessing the utility of these parameters in predicting early HAT. A retrospective review of 144 pediatric recipients (73 males, 71 females) who underwent routine Doppler US in the first week after LDLT was undertaken, and changes in hepatic arterial hemodynamics were assessed. The HARI and HAPSV were compared in patients with early HAT (defined as occurring in the first postoperative week) and a control group, and the utility of these parameters in predicting early HAT after LDLT was determined. A total of 11 pediatric recipients experienced early HAT, being diagnosed on average four and a half days after LDLT. HARI and HAPSV values were significantly different between the early HAT group and controls. HARI values <0.6 on the day before the onset of early HAT were able to predict HAT development with a sensitivity of 81.8% and specificity of 95.2%. This provides evidence for routine Doppler US examination in these patients and supports consideration of more intensive anticoagulation in these high-risk patients.

Health-related quality of life and sleep among Chinese children after living donor liver transplantation.

LDLT is a well-established treatment for most terminal liver diseases in children. Survival rates have improved, yet few studies have considered HRQoL or sleep problems in LDLT recipients. In this cross-sectional study, we enrolled 51 children who had undergone LDLT in Renji Hospital. PedsQL(™) 4.0 Generic Core Scales, PedsQL(™) 3.0 Transplant Module, and Pediatric Sleep Questionnaire were used to assess outcomes. Of all participants, 11.8% (6/51) reported low total HRQoL scores. Participants' scores on most HRQoL subscales were comparable to the scores of healthy children. However, compared with solid organ transplant recipients, LDLT recipients scored significantly lower in About My Medicines II (t = 3.092, p = 0.002) and Worry (t = 2.760, p = 0.006). Sleep problems (41.2%) were common among participants. Hierarchical regression analyses showed that SRBD accounted for significant variance in HRQoL on total generic HRQoL (R(2) = 0.446, p < 0.001), psychosocial health (R(2) = 0.372, p = 0.001), physical health (R(2) = 0.345, p = 0.003), total transplant-specific HRQoL (R(2) = 0.514, p < 0.001), About My Medicines I (R(2) = 0.365, p = 0.013), My Transplant and Others (R(2) = 0.334, p = 0.005), Pain and Hurt (R(2) = 0.544, p < 0.001), Worry (R(2) = 0.401, p = 0.001), Treatment Anxiety (R(2) = 0.526, p < 0.001), How I Look (R(2) = 0.221, p = 0.040), and Communication (R(2) = 0.343, p = 0.012). In conclusion, sleep problems are non-negligible in children after LDLT and predicted significant variance on HRQoL.

Influence of graft size matching on outcomes of infantile living donor liver transplantation.

We aimed to assess the impact of size mismatching between grafts and recipients on outcomes of infants or small children after LDLT. Between October 2006 and December 2014, 129 LDLT recipients weighing no more than 8 kg were retrospectively analyzed. The entire cohort was categorized into three groups by GRWR: GRWR < 3.0% (group A, n = 38), 3.0% ≤ GRWR < 4.0% (group B, n = 61), and GRWR ≥ 4.0% (group C, n = 30). Baseline characteristics were similar among groups A, B, and C. Compared with groups A and B, post-transplant alanine aminotransferase and aspartate aminotransferase within seven days were significantly higher in group C; however, differences between total bilirubin and albumin after transplantation were not prominent. Moreover, incidences of surgical complications, perioperative deaths, infections, and acute rejections were all comparable among the three groups. Five-yr patient survival rates for groups A, B, and C were 89.5%, 88.9%, and 81.6%, respectively (p = 0.872), and the graft survival rates were 89.5%, 86.6%, and 81.6%, respectively (p = 0.846). In conclusion, GRWR between 1.9% and 5.8% would not cause noticeable adverse events for infantile LDLT recipients ≤ 8 kg. However, there is still a role for considering reduction in the graft mass as an applicable strategy in selected cases.

Down-Regulated NRSN2 Promotes Cell Proliferation and Survival Through PI3K/Akt/mTOR Pathway in Hepatocellular Carcinoma.

BACKGROUND AND AIMS: Neurensin-2 (NRSN2) is a neuronal membrane protein; previous reports indicated that it might function as a tumor suppressor in hepatocellular carcinoma (HCC). However, its biological functions and associated mechanisms remain unknown. In the current study, we aimed to investigate the biological functions and possible mechanisms of neurensin-2. METHODS: The mRNA and protein level of NRSN2 in HCC has tissues and cell lines were detected by quantitative real-time PCR, immunohistochemistry staning and western blot. Overexpressing and silencing the level of NRSN2 in HCC cell lines were used to investigate the role of NRSN2 in HCC. CCK-8 assays, SA-ß gel staining, Annexin V/PI staining, quantitative real-time PCR and western blot were employed to explore the role and mechanisms of HCC. RESULTS: NRSN2 was more commonly down-regulated HCC tissues compared with adjacent tissues, and the expression pattern of NRSN2 was not only closely correlated with tumor size and TNM stage but also negatively correlated with patient prognosis. Both loss and gain function assays revealed that NRSN2 inhibits cancer cell proliferation and promotes cancer cell senescence and apoptosis. We further found that NRSN2 might regulate PI3K/AKT signaling and p53/p21 pathway to exert its role in HCC cell proliferation, senescence and apoptosis. CONCLUSION: Our study validates the suppressive role of NRSN2 in both clinicopathologic and biological aspects in HCC tumorigenesis.

Preoperative hepatic hemodynamics in the prediction of early portal vein thrombosis after liver transplantation in pediatric patients with biliary atresia.

BACKGROUND: Portal vein thrombosis (PVT) is one of the main vascular complications after liver transplantation (LT), especially in pediatric patients with biliary atresia (BA). This study aimed to assess the preoperative hepatic hemodynamics in pediatric patients with BA using Doppler ultrasound and determine whether ultrasonographic parameters may predict early PVT after LT. METHODS: One hundred and twenty-eight pediatric patients with BA younger than 3 years of age underwent Doppler ultrasound within seven days before LT, between October 2006 and June 2013. The preoperative hepatic hemodynamic parameters were then compared between patients with early PVT (within 1 month following LT) and those without PVT. Receiver operating characteristic analysis was performed to determine the optimal cutoff value for predicting early PVT. RESULTS: Of the 128 transplant recipients, 41 (32.03%) had a hypoplastic portal vein (PV), 52 (40.63%) had hepatofugal PV flow and 40 (31.25%) had a high hepatic artery resistance index (HARI) of ≥1. Nine cases (7.03%) experienced early PVT. A PV diameter ≤4 mm (sensitivity 88.89%, specificity 72.27%), and a hepatofugal PV flow (sensitivity 77.78%, specificity 62.18%) with a high HARI ≥1 (sensitivity 77.78%, specificity 72.27%) were hepatic hemodynamic risk factors for early PVT. CONCLUSIONS: Hepatic hemodynamic disturbances in pediatric recipients with BA were more common. Small PV diameter (≤4 mm) and hepatofugal PV flow combined with high HARI (≥1) are strong warning signs of early PVT after LT in pediatric patients with BA. Intense monitoring of vascular patency and prophylactic thrombolytic therapy should be considered in pediatric patients undergoing LT for BA.

CYP3A5 genotypes affect tacrolimus pharmacokinetics and infectious complications in Chinese pediatric liver transplant patients.

Little information is available regarding the impact of cytochrome P450 (CYP) 3A5 on the metabolism of TAC in infant LTx. Therefore, the CYP3A5 genotype of Chinese pediatric recipients (intestine) as well as donors (graft liver) was performed for the purpose of establishing an optimal dosage regimen in children. Sixty-four patients were divided according to CYP3A5 genotype (expression of *1 allele: EX and NEX) for each recipient (R) and donor (D), EX-R/EX-D (n = 21), EX-R/NEX-D (n = 8), NEX-R/EX-D (n = 8) and NEX-R/NEX-D (n = 27). Results indicated that initial TAC daily dose requirement was higher among EX-R/EX-D children compared with those who did not express CYP3A5 (0.28 ± 0.10 vs. 0.19 ± 0.08 mg/kg/day, p < 0.01). CYP3A5 expression contributed an overall of 38.35% to its C/D ratios, and graft liver was a key determinant. Additionally, the EX-R/EX-D group showed significantly higher incidence of infectious complications, lower immune response and was an independent risk factor for the development of infections (odds ratio 3.86, p = 0.025). Donor CYP3A5 expression partially explains TAC dose requirement, the effect of CYP3A5 variation may influence clinical outcomes; therefore, monitoring immune response may be important for preventing risks associated with under- and over-immunosuppression.

Environmental quality assessment of heavy metals in the Rongcheng offshore area, Shandong Peninsula, China.

Eighteen surface sediment samples collected from the Rongcheng offshore area of China in 2021 were analyzed for heavy metal concentrations, sources, and pollution status. The Cu, Zn, Cr, Cd, As, and total organic carbon (TOC) distributions were similar. In contrast, the distributions of Pb and Hg were irregular, and high concentrations appeared in two or several areas. Occasional adverse effects were observed from pollution caused by Cu, Pb, and As, and none of the heavy metal concentrations exceeded the probable effect level (PEL). The Pearson's correlation coefficient, geoaccumulation index, and principal component analysis were used to distinguish the sources and assess the pollution risk of heavy metals. The results showed that heavy metals did not pollute the surface sediments in the Rongcheng offshore area and that the metals were mainly derived from natural sources.

Linkage Mapping and Discovery of Candidate Genes for Drought Tolerance in Rice During the Vegetative Growth Period.

Drought is a major abiotic stress affecting crop yields. Mapping quantitative trait loci (QTLs) and mining genes for drought tolerance in rice are important for identifying gene functions and targets for molecular breeding. Here, we performed linkage analysis of drought tolerance using a recombinant inbred line population derived from Jileng 1 (drought sensitive) and Milyang 23 (drought tolerant). An ultra-high-density genetic map, previously constructed by our research team using genotype data from whole-genome sequencing, was used in combination with phenotypic data for rice grown under drought stress conditions in the field in 2017-2019. Thirty-nine QTLs related to leaf rolling index and leaf withering degree were identified, and QTLs were found on all chromosomes except chromosomes 6, 10, and 11. qLWD4-1 was detected after 32 days and 46 days of drought stress in 2017 and explained 7.07-8.19% of the phenotypic variation. Two loci, qLRI2-2 and qLWD4-2, were identified after 29, 42, and 57 days of drought stress in 2018. These loci explained 10.59-17.04% and 5.14-5.71% of the phenotypic variation, respectively. There were 281 genes within the QTL interval. Through gene functional annotation and expression analysis, two candidate genes, Os04g0574600 and OsCHR731, were found. Quantitative reverse transcription PCR analysis showed that the expression levels of these genes were significantly higher under drought stress than under normal conditions, indicating positive regulation. Notably, Os04g0574600 was a newly discovered drought tolerance gene. Haplotype analysis showed that the RIL population carried two haplotypes (Hap1 and Hap2) of both genes. Lines carrying Hap2 exhibited significantly or extremely stronger drought tolerance than those carrying Hap1, indicating that Hap2 is an excellent haplotype. Among rice germplasm resources, there were two and three haplotypes of Os04g0574600 and OsCHR731, respectively. A high proportion of local rice resources in Sichuan, Yunnan, Anhui, Guangdong and Fujian provinces had Hap of both genes. In wild rice, 50% of accessions contained Hap1 of Os04g0574600 and 50% carried Hap4; 13.51%, 59.46% and 27.03% of wild rice accessions contained Hap1, Hap2, and Hap3, respectively. Hap2 of Os04g0574600 was found in more indica rice resources than in japonica rice. Therefore, Hap2 has more potential for utilization in future drought tolerance breeding of japonica rice.