Maize requires arogenate dehydratase 2 for resistance to Ustilago maydis and plant development.

Maize (Zea mays) smut is a common biotrophic fungal disease caused by Ustilago maydis and leads to low maize yield. Maize resistance to U. maydis is a quantitative trait. However, the molecular mechanism underlying the resistance of maize to U. maydis is poorly understood. Here, we reported that a maize mutant caused by a single gene mutation exhibited defects in both fungal resistance and plant development. maize mutant highly susceptible to U. maydis (mmsu) with a dwarf phenotype forms tumors in the ear. A map-based cloning and allelism test demonstrated that 1 gene encoding a putative arogenate dehydratase/prephenate dehydratase (ADT/PDT) is responsible for the phenotypes of the mmsu and was designated as ZmADT2. Combined transcriptomic and metabolomic analyses revealed that mmsu had substantial differences in multiple metabolic pathways in response to U. maydis infection compared with the wild type. Disruption of ZmADT2 caused damage to the chloroplast ultrastructure and function, metabolic flux redirection, and reduced the amounts of salicylic acid (SA) and lignin, leading to susceptibility to U. maydis and dwarf phenotype. These results suggested that ZmADT2 is required for maintaining metabolic flux, as well as resistance to U. maydis and plant development in maize. Meanwhile, our findings provided insights into the maize response mechanism to U. maydis infection.

N6-methyladenosine transcriptome-wide profiles of maize kernel development.

Maize (Zea mays L.) kernel development is a complex and dynamic process involving cell division and differentiation, into a variety of cell types. Epigenetic modifications, including DNA methylation, play a pivotal role in regulating this process. N6-methyladenosine modification is a universal and dynamic post-transcriptional epigenetic modification that is involved in the regulation of plant development. However, the role of N6-methyladenosine in maize kernel development remains unknown. In this study, we have constructed transcriptome-wide profiles for maize kernels at various stages of early development. Utilizing a combination of MeRIP-seq and RNA-seq analysis, we identified a total of 11,170, 10,973, 11,094, 11,990, 12,203 and 10,893 N6-methyladenosine peaks in maize kernels at 0, 2, 4, 6, 8, and 12 days after pollination, respectively. These N6-methyladenosine modifications were primarily deposited at the 3'-UTRs and were associated with the conserved motif-UGUACA. Additionally, we found that conserved N6-methyladenosine modification are involved in the regulation of genes that are ubiquitously expressed during kernel development. Further analysis revealed that N6-methyladenosine peak intensity was negatively correlated with the mRNA abundance of these ubiquitously expressed genes. Meanwhile, we employed phylogenetic analysis to predict potential regulatory proteins involved in maize kernels development and identified several that participate in the regulation of N6-methyladenosine modifications. Collectively, our results suggest the existence of a novel post-transcriptional epigenetic modification mechanism involved in the regulation of maize kernels development, thereby providing a novel perspective for maize molecular breeding.

A MYB-related transcription factor ZmMYBR29 is involved in grain filling.

BACKGROUND: The endosperm serves as the primary source of nutrients for maize (Zea mays L.) kernel embryo development and germination. Positioned at the base of the endosperm, the transfer cells (TCs) of the basal endosperm transfer layer (BETL) generate cell wall ingrowths, which enhance the connectivity between the maternal plant and the developing kernels. These TCs play a crucial role in nutrient transport and defense against pathogens. The molecular mechanism underlying BETL development in maize remains unraveled. RESULTS: This study demonstrated that the MYB-related transcription factor ZmMYBR29, exhibited specific expression in the basal cellularized endosperm, as evidenced by in situ hybridization analysis. Utilizing the CRISPR/Cas9 system, we successfully generated a loss-of-function homozygous zmmybr29 mutant, which presented with smaller kernel size. Observation of histological sections revealed abnormal development and disrupted morphology of the cell wall ingrowths in the BETL. The average grain filling rate decreased significantly by 26.7% in zmmybr29 mutant in comparison to the wild type, which impacted the dry matter accumulation within the kernels and ultimately led to a decrease in grain weight. Analysis of RNA-seq data revealed downregulated expression of genes associated with starch synthesis and carbohydrate metabolism in the mutant. Furthermore, transcriptomic profiling identified 23 genes that expressed specifically in BETL, and the majority of these genes exhibited altered expression patterns in zmmybr29 mutant. CONCLUSIONS: In summary, ZmMYBR29 encodes a MYB-related transcription factor that is expressed specifically in BETL, resulting in the downregulation of genes associated with kernel development. Furthermore, ZmMYBR29 influences kernels weight by affecting the grain filling rate, providing a new perspective for the complementation of the molecular regulatory network in maize endosperm development.

VgrG Spike Dictates PAAR Requirement for the Assembly of the Type VI Secretion System.

Widely employed by Gram-negative pathogens for competition and pathogenesis, the type six protein secretion system (T6SS) can inject toxic effectors into neighboring cells through the penetration of a spear-like structure comprising a long Hcp tube and a VgrG-PAAR spike complex. The cone-shaped PAAR is believed to sharpen the T6SS spear for penetration but it remains unclear why PAAR is required for T6SS functions in some bacteria but dispensable in others. Here, we report the conditional requirement of PAAR for T6SS functions in Aeromonas dhakensis, an emerging human pathogen that may cause severe bacteremia. By deleting the two PAAR paralogs, we show that PAAR is not required for T6SS secretion, bacterial killing, or specific effector delivery in A. dhakensis. By constructing combinatorial PAAR and vgrG deletions, we demonstrate that deletion of individual PAAR moderately reduced T6SS functions but double or triple deletions of PAAR in the vgrG deletion mutants severely impaired T6SS functions. Notably, the auxiliary-cluster-encoded PAAR2 and VgrG3 are less critical than the main-cluster-encoded PAAR1 and VgrG1&2 proteins to T6SS functions. In addition, PAAR1 but not PAAR2 contributes to antieukaryotic virulence in amoeba. Our data suggest that, for a multi-PAAR T6SS, the variable role of PAAR paralogs correlates with the VgrG-spike composition that collectively dictates T6SS assembly. IMPORTANCE Gram-negative bacteria often encode multiple paralogs of the cone-shaped PAAR that sits atop the VgrG-spike and is thought to sharpen the spear-like T6SS puncturing device. However, it is unclear why PAAR is required for the assembly of some but not all T6SSs and why there are multiple PAARs if they are not required. Our data delineate a VgrG-mediated conditional requirement for PAAR and suggest a core-auxiliary relationship among different PAAR-VgrG modules that may have been acquired sequentially by the T6SS during evolution.

VgrG-dependent effectors and chaperones modulate the assembly of the type VI secretion system.

The type VI secretion system (T6SS) is a spear-like nanomachine found in gram-negative pathogens for delivery of toxic effectors to neighboring bacterial and host cells. Its assembly requires a tip spike complex consisting of a VgrG-trimer, a PAAR protein, and the interacting effectors. However, how the spike controls T6SS assembly remains elusive. Here we investigated the role of three VgrG-effector pairs in Aeromonas dhakensis strain SSU, a clinical isolate with a constitutively active T6SS. By swapping VgrG tail sequences, we demonstrate that the C-terminal ~30 amino-acid tail dictates effector specificity. Double deletion of vgrG1&2 genes (VgrG3+) abolished T6SS secretion, which can be rescued by ectopically expressing chimeric VgrG3 with a VgrG1/2-tail but not the wild type VgrG3. In addition, deletion of effector-specific chaperones also severely impaired T6SS secretion, despite the presence of intact VgrG and effector proteins, in both SSU and Vibrio cholerae V52. We further show that SSU could deliver a V. cholerae effector VasX when expressing a plasmid-borne chimeric VgrG with VasX-specific VgrG tail and chaperone sequences. Pull-down analyses show that two SSU effectors, TseP and TseC, could interact with their cognate VgrGs, the baseplate protein TssK, and the key assembly chaperone TssA. Effectors TseL and VasX could interact with TssF, TssK and TssA in V. cholerae. Collectively, we demonstrate that chimeric VgrG-effector pairs could bypass the requirement of heterologous VgrG complex and propose that effector-stuffing inside the baseplate complex, facilitated by chaperones and the interaction with structural proteins, serves as a crucial structural determinant for T6SS assembly.

Defective kernel 66 encodes a GTPase essential for kernel development in maize.

The mitochondrion is a semi-autonomous organelle that provides energy for cell activities through oxidative phosphorylation. In this study, we identified a defective kernel 66 (dek66)-mutant maize with defective kernels. We characterized a candidate gene, DEK66, encoding a ribosomal assembly factor located in mitochondria and possessing GTPase activity (which belongs to the ribosome biogenesis GTPase A family). In the dek66 mutant, impairment of mitochondrial structure and function led to the accumulation of reactive oxygen species and promoted programmed cell death in endosperm cells. Furthermore, the transcript levels of most of the key genes associated with nutrient storage, mitochondrial respiratory chain complex, and mitochondrial ribosomes in the dek66 mutant were significantly altered. Collectively, the results suggest that DEK66 is essential for the development of maize kernels by affecting mitochondrial function. This study provides a reference for understanding the impact of a mitochondrial ribosomal assembly factor in maize kernel development.

The novel E-subgroup pentatricopeptide repeat protein DEK55 is responsible for RNA editing at multiple sites and for the splicing of nad1 and nad4 in maize.

BACKGROUND: Pentatricopeptide repeat (PPR) proteins compose a large protein family whose members are involved in both RNA processing in organelles and plant growth. Previous reports have shown that E-subgroup PPR proteins are involved in RNA editing. However, the additional functions and roles of the E-subgroup PPR proteins are unknown. RESULTS: In this study, we developed and identified a new maize kernel mutant with arrested embryo and endosperm development, i.e., defective kernel (dek) 55 (dek55). Genetic and molecular evidence suggested that the defective kernels resulted from a mononucleotide alteration (C to T) at + 449 bp within the open reading frame (ORF) of Zm00001d014471 (hereafter referred to as DEK55). DEK55 encodes an E-subgroup PPR protein within the mitochondria. Molecular analyses showed that the editing percentage of 24 RNA editing sites decreased and that of seven RNA editing sites increased in dek55 kernels, the sites of which were distributed across 14 mitochondrial gene transcripts. Moreover, the splicing efficiency of nad1 introns 1 and 4 and nad4 intron 1 significantly decreased in dek55 compared with the wild type (WT). These results indicate that DEK55 plays a crucial role in RNA editing at multiple sites as well as in the splicing of nad1 and nad4 introns. Mutation in the DEK55 gene led to the dysfunction of mitochondrial complex I. Moreover, yeast two-hybrid assays showed that DEK55 interacts with two multiple organellar RNA-editing factors (MORFs), i.e., ZmMORF1 (Zm00001d049043) and ZmMORF8 (Zm00001d048291). CONCLUSIONS: Our results demonstrated that a mutation in the DEK55 gene affects the mitochondrial function essential for maize kernel development. Our results also provide novel insight into the molecular functions of E-subgroup PPR proteins involved in plant organellar RNA processing.

DEK43 is a P-type pentatricopeptide repeat (PPR) protein responsible for the Cis-splicing of nad4 in maize mitochondria.

Mitochondria, the main energy transducers in plant cells, require the proper assembly of respiratory chain complexes I-V for their function. The NADH dehydrogenase 4 (nad4) gene encodes mitochondrial respiratory chain complex I subunit IV, but the mechanism underlying nad4 transcript splicing is unclear. Here, we report that the P-type pentatricopeptide repeat (PPR) protein DEFECTIVE KERNEL 43 (DEK43) is responsible for cis-splicing of the nad4 transcript in maize. We demonstrate that DEK43 localizes to both the nucleus and mitochondria. The mutation of Dek43 resulted in embryo-lethal and light-colored defective kernels. Among the 22 mitochondrial group II introns, the splicing efficiency of nad4 introns 1 and 3 was reduced by up to 50% compared to the wild type. The levels of complex I and supercomplex I+III2 were also reduced in dek43. Furthermore, in-gel NADH dehydrogenase assays indicated that the activities of these complexes were significantly reduced in dek43. Further, the mitochondrial ultrastructure was altered in the mutant. Together, our findings indicate that DEK43, a dual-localized PPR protein, plays an important role in maintaining mitochondrial function and maize kernel development.

Pentatricopeptide repeat protein DEK40 is required for mitochondrial function and kernel development in maize.

Pentatricopeptide repeat (PPR) proteins are one of the largest protein families, which consists of >400 members in most species. However, the molecular functions of many PPR proteins are still uncharacterized. Here, we isolated a maize mutant, defective kernel 40 (dek40). Positional cloning, and genetic and molecular analyses revealed that DEK40 encodes a new E+ subgroup PPR protein that is localized in the mitochondrion. DEK40 recognizes and directly binds to cox3, nad2, and nad5 transcripts and functions in their processing. In the dek40 mutant, abolishment of the C-to-U editing of cox3-314, nad2-26, and nad5-1916 leads to accumulated reactive oxygen species and promoted programmed cell death in endosperm cells due to the dysfunction of mitochondrial complexes I and IV. Furthermore, RNA sequencing analysis showed that gene expression in some pathways, such as glutathione metabolism and starch biosynthesis, was altered in the dek40 mutant compared with the wild-type control, which might be involved in abnormal development of the maize mutant kernels. Thus, our results provide solid evidence on the molecular mechanism underlying RNA editing by DEK40, and extend our understanding of PPR-E+ type protein in editing functions and kernel development in maize.

Synchronous cancers of gallbladder carcinoma and combined hepatocellular cholangiocarcinoma: an unusual case and literature review.

BACKGROUND: Synchronous primary cancers in gallbladder and liver are rarely reported. Here we report an unusual case of synchronous cancers of gallbladder carcinoma and combined hepatocellular cholangiocarcinoma. CASE PRESENTATION: Several lesions in the gallbladder and in adjacent parenchyma of liver were discovered in a 65-years-old woman by imaging examination. Surgical resection was performed following a diagnosis of primary gallbladder carcinoma with local hepatic metastasis. Histological examination confirmed the diagnosis of primary gallbladder carcinoma, and the lesions in the liver consisted of hepatocellular carcinoma simultaneously with cholangiocarcinoma. Adjuvant chemoradiation therapy was not performed due to the patient's refusal of the treatment. Unfortunately, the patient died of widespread metastasis 8 months after the operation. CONCLUSIONS: The disease needed to be differentially diagnosed from gallbladder carcinoma with hepatic metastasis. Aggressive surgical approach should be based on a balance between the risk of surgery (morbidity and mortality) and the outcome.

Effects of antioxidant system on coronary artery lesions in patients with abnormal glucose metabolism.

OBJECTIVE: To evaluate the effects of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) system on the range and severity of coronary artery lesions in patients with abnormal glucose metabolism. METHODS: This study included 766 patients with abnormal glucose metabolism. Levels of fasting blood lipids, blood glucose, CAT, SOD, GSH, glutathione reductase (GR), and glutathione peroxidase (GSH-Px) were measured in all the patients. Coronarography was performed, and the degree of the lesions in each coronary artery was quantitatively analyzed using the Gensini scoring system. RESULTS: In patients with impaired glucose regulation and diabetes, the number of coronary artery branches with stenosis and the Gensini scores were inversely correlated with the plasma levels of CAT, SOD, GSH, GH, and GSH-Px (P < 0.001). Patients were grouped according to the Gensini scores. As the scores increased, the levels of CAT, SOD, GSH, GSH-Px, and GR gradually decreased. Logistic gradual regression analysis showed that GSH-Px and CAT were independent risk factors associated with the coronary artery lesions in three or more branches. CONCLUSIONS: Decreased plasma levels of CAT, SOD, GSH, GR, and GSH-Px were inversely correlated, at least to some extent, with the extent of coronary artery lesions. Particularly, GSH-Px and CAT were independent risk factors associated with coronary artery lesions involving three or more branches. This suggests that long-term hyperglycemia leads to enhancement of oxidative stress.

Screening of morphology-related genes based on predator-induced transcriptome sequencing and the functional analysis of Dagcut gene in Daphnia galeata.

High fish predation pressure can trigger "induced defense" in Daphnia species, resulting in phenotypic plasticity in morphology, behavior, or life-history traits. The molecular mechanisms of defense morphogenesis (e.g., the tail spine and helmet) in Daphnia remain unclear. In the present study, the tail spine, helmet, and body of Daphnia galeata under fish and non-fish kairomones conditions were collected for transcriptome analysis. A total of 24 candidate genes related to the morphological defense of D. galeata were identified, including 2 trypsin, one cuticle protein, 1 C1qDC protein, and 2 ferritin genes. The function of the Dagcut gene (D. galeata cuticle protein gene) in relation to tail spine morphology was assessed using RNA interference (RNAi). Compared with the EGFP (Enhanced green fluorescent protein) treatment, after RNAi, the expression levels of the Dagcut gene (D. galeata cuticle protein gene) showed a significant decrease. Correspondingly, the tail spines of the offspring produced by D. galeata after RNAi of the Dagcut gene appeared curved during the experiment. In whole-mount in situ hybridization, a clear signal site was detected on the tail spine of D. galeata before RNAi which disappeared after RNAi. Our results suggest that the Dagcut gene may play an important role in tail spine formation of D. galeata, and will provide a theoretical basis for studying the molecular mechanisms of the morphological plasticity in cladocera in the future.

Tubule-specific cyclin-dependent kinase 12 knockdown potentiates kidney injury through transcriptional elongation defects.

Direct tubular injury caused by several medications, especially chemotherapeutic drugs, is a common cause of AKI. Inhibition or loss of cyclin-dependent kinase 12 (CDK12) triggers a transcriptional elongation defect that results in deficiencies in DNA damage repair, producing genomic instability in a variety of cancers. Notably, 10-25% of individuals developed AKI after treatment with a CDK12 inhibitor, and the potential mechanism is not well understood. Here, we found that CDK12 was downregulated in the renal tubular epithelial cells in both patients with AKI and murine AKI models. Moreover, tubular cell-specific knockdown of CDK12 in mice enhanced cisplatin-induced AKI through promotion of genome instability, apoptosis, and proliferative inhibition, whereas CDK12 overexpression protected against AKI. Using the single molecule real-time (SMRT) platform on the kidneys of CDK12RTEC+/- mice, we found that CDK12 knockdown targeted Fgf1 and Cast through transcriptional elongation defects, thereby enhancing genome instability and apoptosis. Overall, these data demonstrated that CDK12 knockdown could potentiate the development of AKI by altering the transcriptional elongation defect of the Fgf1 and Cast genes, and more attention should be given to patients treated with CDK12 inhibitors to prevent AKI.

The construction and validation of a frailty risk prediction model for older adults with lung cancer: A cross-sectional study.

OBJECTIVE: We aimed to construct and internally validate a frailty risk prediction model in older adults with lung cancer. METHOD: In total, 538 patients were recruited in a grade A tertiary cancer hospital in Tianjin, and patients were randomly divided into the training group (n = 377) and the testing group (n = 166) at a ratio of 7:3. The Frailty Phenotype scale was used to identify frailty and logistic regression analysis was used to identify the risk factors and establish a frailty risk prediction model. RESULTS: In the training group, logistic regression showed that age, fatigue-related symptom cluster, depression, nutritional status, D-dimer level, albumin level, presence of comorbidities, and disease course were independent risk factors for frailty. The areas under the curve (AUCs) of the training and testing groups were 0.921 and 0.872, respectively. A calibration curve of P = 0.447 validated model calibration. The decision curve analysis demonstrated greater clinical benefit when the threshold probability was >20%. CONCLUSION: The prediction model had a favorable prediction power for determining the risk of frailty, contributing to the prevention and screening of frailty. Patients with a frailty risk score of more than 0.374 should be regularly monitored for frailty and receive personalized preventive interventions.

Long-Term Cardiac Disease- and Cancer-Associated Mortalities in Patients With Non-Metastatic Stomach Adenocarcinoma Receiving Resection and Chemotherapy: A Large Competing-Risk Population-Based Cohort Study.

Background: The survival of patients with non-metastatic gastric adenocarcinoma (nmGaC), who are receiving more and more frequently chemotherapy, has improved throughout the last decades, while treatment-caused cardiotoxicity remains a major concern. This study aimed to investigate competing causes of mortality and prognostic factors within a large cohort of patients with resected nmGaC, and to describe the heart-specific mortalities of patients undergoing resection and chemotherapy and of all resected patients. Methods: In this population-based cohort study, data on patients diagnosed with nmGaC from 2004 through 2016, managed with resection with or without chemotherapy, followed up until the end of 2016, and surviving ≥ 1 month were retrieved from the US Surveillance, Epidemiology, and End Results-18 Program. Cumulative mortality functions were calculated. Prognostic factors for heart- and cancer-specific mortalities were evaluated using both multivariable-adjusted Fine-Gray subdistribution and cause-specific hazard functions. Results: Together 21,257 patients with resected nmGaC were eligible for analysis with an accumulated follow-up of 73,711 person-years, where 10,718 (50%) also underwent chemotherapy. Mortalities were overestimated when using the Kaplan-Meier method. Heart diseases were the most common non-cancer cause of mortality. Compared with all resected patients, heart-specific mortality of those also receiving chemotherapy was lower overall and especially at older ages. In the total group of patients, the 8-year cumulative mortalities from heart diseases were 4.4% and 2.0% in resected patients and those also receiving chemotherapy, respectively; in patients ≥ 80 years, the heart disease-specific mortalities were as high as 11.1% and 6.5%, respectively. In overall patients undergoing resection, older ages, black ethnicity, and location at gastric antrum/pylorus were associated with increased heart-specific mortality, while more recent period, female sex, Asian/Pacific Islanders, invasion of serosa, and more positive lymph nodes were associated with lower heart-specific mortality; among those further receiving chemotherapy, only the associations with period of diagnosis, age, and ethnicity were significant. Associations with older ages were stronger for heart-specific mortality than for cancer-associated mortality. Conclusions: Among survivors with resected nmGaC receiving chemotherapy, heart-specific mortality, the most common one among non-cancer causes of mortality, is not higher compared to overall resected patients in this observational study, suggesting that chemotherapy may be relatively safely administered to selected patients under strict indications. Age and ethnicity were major factors associated with heart-specific mortality in both overall resected patients and those further receiving chemotherapy. Overall and stratified cause-specific cumulative incidences of mortality are provided, which can be more clinically useful than the Kaplan-Meier estimates. Our study provides clinically useful evidence for tailored patient management.

MiR-155 deficiency protects renal tubular epithelial cells from telomeric and genomic DNA damage in cisplatin-induced acute kidney injury.

Rationale: Cisplatin nephrotoxicity is an important cause of acute kidney injury (AKI), limiting cisplatin application in cancer therapy. Growing evidence has suggested that genome instability, telomeric dysfunction, and DNA damage were involved in the tubular epithelial cells (TECs) damage in cisplatin-induced AKI (cAKI). However, the exact mechanism is largely unknown. Methods: We subjected miR-155-/- mice and wild-type controls, as well as HK-2 cells, to cAKI models. We assessed kidney function and injury with standard techniques. The cell apoptosis and DNA damage of TECs were evaluated both in vivo and in vitro. Telomeres were measured by the fluorescence in situ hybridization. Results: The expression level of miR-155 was upregulated in cAKI. Inhibition of miR-155 expression protected cisplatin-induced AKI both in vivo and in vitro. Compared with wild-type mice, miR-155-/- mice had reduced mortality, improved renal function and pathological damage after cisplatin intervention. Moreover, inhibition of miR-155 expression attenuated TECs apoptosis and DNA damage. These protective effects were caused by increasing expression of telomeric repeat binding factor 1 (TRF1) and cyclin-dependent kinase 12 (CDK12), thereby limiting the telomeric dysfunction and the genomic DNA damage in cAKI. Conclusion: We demonstrated that miR-155 deficiency could significantly attenuate pathological damage and mortality in cAKI through inhibition of TECs apoptosis, genome instability, and telomeric dysfunction, which is possibly regulated by the increasing expression of TRF1 and CDK12. This study will provide a new molecular strategy for the prevention of cAKI.

A nitrate transporter encoded by ZmNPF7.9 is essential for maize seed development.

Nitrogen is an essential macronutrient for plants and regulates many aspects of plant growth and development. Nitrate is one of the major forms of nitrogen in plants. However, the role of nitrate uptake and allocation in seed development is not fully understood. Here, we identified the maize (Zea mays) small-kernel mutant zmnpf7.9 and characterized the candidate gene, ZmNPF7.9, which was the same gene as nitrate transport 1.5 (NRT1.5) in maize. This gene is specifically expressed in the basal endosperm transfer layer cells of maize endosperm. Dysfunction of ZmNPF7.9 resulted in delayed endosperm development, abnormal starch deposition and decreased hundred-grain weight. Functional analysis of cRNA-injected Xenopus oocytes showed that ZmNPF7.9 is a low-affinity, pH-dependent bidirectional nitrate transporter. Moreover, the amount of nitrate in mature seeds of the zmnpf7.9 mutant was reduced. These suggest that ZmNPF7.9 is involved in delivering nitrate from maternal tissues to the developing endosperm. Moreover, most of the key genes associated with glycolysis/gluconeogenesis, carbon fixation, carbon metabolism and biosynthesis of amino acids pathways in the zmnpf7.9 mutant were significantly down-regulated. Thus, our results demonstrate that ZmNPF7.9 plays a specific role in seed development and grain weight by regulating nutrition transport and metabolism, which might provide useful information for maize genetic improvement.

Prognostic value and predictive threshold of tumor volume for patients with locally advanced nasopharyngeal carcinoma receiving intensity-modulated radiotherapy.

BACKGROUND: Gross target volume of primary tumor (GTV-P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma (NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity-modulated radiotherapy (IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to find a suitable cut-off value of GTV-P for prognosis prediction. METHODS: Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver operating characteristic (ROC) curves were used to identify the cut-off values of GTV-P for the prediction of different endpoints [overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS)] and to test the prognostic value of GTV-P when compared with that of the American Joint Committee on Cancer T staging system. RESULTS: The 358 patients with locally advanced NPC were divided into two groups by the cut-off value of GTV-P as determined using ROC curves: 219 (61.2%) patients with GTV-P ≤46.4 mL and 139 (38.8%) with GTV-P >46.4 mL. The 3-year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV-P ≤46.4 mL than in those with GTV-P > 46.4 mL (all P < 0.05). Multivariate analysis indicated that GTV-P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve verified that the predictive ability of GTV-P was superior to that of T category (P < 0.001). The cut-off values of GTV-P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively. CONCLUSION: In patients with locally advanced NPC, GTV-P >46.4 mL is an independent unfavorable prognostic indicator for survival after IMRT, with a prognostic value superior to that of T category.