Substation of vermicompost mitigates Cd toxicity, improves rice yields and restores bacterial community in a Cd-contaminated soil in Southern China

Cadmium (Cd) contamination in agricultural soil is a global concern for soil health and food sustainability because it can cause Cd accumulation in cereal grains. An in-situ stabilizing technology (using organic amendments) has been widely used for Cd remediation in arable lands. Therefore, the current study examined the influence of vermicompost (VC) on soil biochemical traits, bacterial community diversity and composition, Cd uptake and accumulation in rice plants and grain yield in a Cd-contaminated soil during the late growing season in 2022. Different doses of VC (i.e., V1 = 0 t ha-1, V2 = 3 t ha-1 and V3 = 6 t ha-1) and two concentrations of Cd (i.e., Cd1 = 0 and Cd2 = 50 mg Cd Kg-1 were used. We performed high-throughput sequencing of 16S ribosomal RNA gene amplicons to characterize soil bacterial communities. The addition of VC considerably affected the diversity and composition of the soil bacterial community; and increased the relative abundance of phyla Chloroflexi, Proteobacteria, Acidobacteriota, Plantomycetota, Gemmatimonadota, Patescibacteria and Firmicute. In addition, VC application, particularly High VC treatment, exhibited the highest bacterial diversity and richness (i.e., Simpson, Shannon, ACE, and Chao 1 indexes) of all treatments. Similarly, the VC application increased the soil chemical traits, including soil pH, soil organic carbon (SOC), available nitrogen (AN), total nitrogen (TN), total potassium (TK), total phosphorous (TP) and enzyme activities (i.e., acid phosphatase, catalase, urease and invertase) compared to non-VC treated soil under Cd stress. The average increase in SOC, TN, AN, TK and TP were 5.75%, 41.15%, 18.51%, 12.31%, 25.45% and 29.67%, respectively, in the High VC treatment (Pos-Cd + VC3) compared with Cd stressed soil. Redundancy analysis revealed that the leading bacterial phyla were associated with SOC, AN, TN, TP and pH, although the relative abundance of Firmicutes, Proteobacteria, Bacteroidata, and Acidobacteria on a phylum basis and Actinobacteria, Gammaproteobacteria and Myxococcia on a class basis, were highly correlated with soil environmental factors. Moreover, the VC application counteracted the adverse effects of Cd on plants and significantly reduced the Cd uptake and accumulation in rice organs, such as roots, stem + leaves and grain under Cd stress conditions. Similarly, applying VC significantly increased the fragrant rice grain yield and yield traits under Cd toxicity. The correlation analysis showed that the increased soil quantities traits were crucial in obtaining high rice grain yield. Generally, the findings of this research demonstrate that the application of VC in paddy fields could be useful for growers in Southern China by sustainably enhancing soil functionality and crop production.

[Analysis of iodine nutritional status of children aged 8-10 years in Zhejiang Province from 2016 to 2021]

Objective: To analyze the iodine nutrition status of children aged 8 to 10 years in Zhejiang Province from 2016 to 2021. Methods: A multi-stage stratified sampling method was used to select non-residential children aged 8 to 10 years from 90 counties in Zhejiang Province. A total of 114 103 children were included in the study from 2016 to 2021. Direct titration method and arsenic-cerium catalytic spectrophotometry were used to detect salt iodine content and urinary iodine level, respectively, to evaluate the iodine nutritional status of children. Ultrasound was used to detect thyroid volume and analyze the current prevalence of goiter in school-age children. Results: The age of 114 103 children was (9.04 ± 0.81) years old, with 50.0% of (57 083) boys. The median of iodine content M (Q1, Q3) in children's household salt was 23.00 (19.80, 25.20) mg/kg, including 17 242 non-iodized salt, 6 173 unqualified iodized salt, and 90 688 qualified iodized salt. The coverage rate of iodized salt was 84.89%, and the coverage rate of qualified iodized salt was 79.48%. The proportion of non-iodized salt increased from 11.85% in 2016 to 16.04% in 2021 (χ2trend=111.427, P<0.001). The median of urinary iodine concentration M (Q1, Q3) in children was 182.50 (121.00, 261.00) μg/L, among which the proportions of iodine deficiency, iodine suitability, iodine over suitability, and iodine excess were 17.25% (19 686 cases), 39.21% (44 745 cases), 26.85% (30 638 cases), and 16.68% (19 034 cases), respectively. The median of urinary iodine concentration in children in inland areas [M (Q1, Q3): 190.90 (128.80, 269.00) μg/L] was significantly higher than that in children in coastal areas [M (Q1, Q3): 173.00 (113.00, 250.30) μg/L] (P<0.001). From 2016 to 2021, a total of 39 134 ultrasound examinations were conducted, and 1 229 cases of thyroid enlargement were detected. The goiter rate was 3.14% (95%CI: 2.97%-3.32%). The incidence of goiter in children in coastal areas [3.45% (95%CI: 3.19%-3.72%), 641/18 604] was higher than that in children in inland areas [2.86% (95%CI: 2.64%-3.10%), 588/20 530] (P=0.001). Conclusion: From 2016 to 2021, the iodine nutrition level of children aged 8-10 years in Zhejiang Province is generally suitable, and the rate of goiter in children meets the limit of iodine deficiency disease elimination standards.

Optimization of liquid fertilizer management improves grain yield, biomass accumulation, and nutrient uptake of late-season indica fragrant rice

BACKGROUND

The use of liquid fertilizer is an effective measure to increase rice yield and nitrogen use efficiency. There has been a lack of information regarding the effects on the grain yield, biomass accumulation, and nutrient uptake in late-season indica fragrant rice of split fertilizer application and of nitrogen management in liquid fertilizer application.

RESULTS

A 2-year field experiment was carried out during 2019 and 2020 with two fragrant rice cultivars grown under differing fertilizer management treatments. Results showed that the fertilization treatments affected the grain yield, yield components, biomass accumulation, and nutrient accumulation significantly. The mean nitrogen recovery efficiency with liquid fertilizer management was greater than in a control treatment corresponding to a practice commonly used by farmers (H2). The effects of nitrogen metabolism enzymes in the leaves of both rice cultivars were stronger with liquid fertilizer treatments than with H2. Grain yield was positively associated with the effective panicle number, spikelets per panicle, dry matter accumulation, N and K accumulation, and the nitrogen metabolism enzymes.

CONCLUSIONS

Optimized liquid fertilizer management increases biomass accumulation, nitrogen utilization efficiency, and nitrogen metabolism. It stabilizes yields and increases the economic benefits of late-season indica fragrant rice. © 2023 Society of Chemical Industry.

Identification and Automated Delineation of Radioresistant Biological Tumor Volume in Nasopharyngeal Carcinoma Based on Magnetic Resonance Imaging Radiomics

PURPOSE/OBJECTIVE(S)

Widespread use of intensity modulated radiotherapy (IMRT) has improved the tumor control rate of nasopharyngeal carcinoma (NPC). However, nearly 20% of the patients with local-advanced NPC would relapse after precise irradiation and 80% of the recurrent lesions occur within the high dose field, suggesting that there are radiation-resistant cancer cell subsets within the tumor. In this context, identification and contouring of radiation resistance region of NPC for dose escalation at primary IMRT could be advantageous. In this work, we proposed a two-step radiomics workflow to predict local relapse and the recurrent region of NPC before primary IMRT.

MATERIALS/METHODS

In this single-center, retrospective study, pre-treatment magnetic resonance (MR) sequences of T1-weighted imaging (T1-w) and contrast-enhanced T1-weighted imaging (CET1-w) were collected from 800 patients of newly diagnosed and non-metastatic NPC between April 2009 and December 2015. The primary gross tumor volume (GTVp) of all patients and the actual recurrent lesion (GTVr) of patients who suffered from local recurrence were manually contoured for further analysis. A two-step complete radiomics workflow was designed to predict tumor recurrence and segment the region. First, least absolute shrinkage and selection operator (LASSO) was utilized for radiomics features selection of GTVp and support vector machine (SVM) was adopted to predict the recurrence. If the model predicts a recurrence, then the workflow utilizes an improved 3D U-Net to segment the recurrent region. Area under receiver operating characteristic curve (ROC-AUC) was used to evaluate the performance of tumor recurrence prediction, and Dice similarity coefficient (DSC) was used to assess the consistence between the actual and predicted GTVr.

RESULTS

Of 800 NPC patients, 95 (11.9%) patients developed in-field local recurrence. For recurrence risk prediction, the SVM ensemble model (T1-w+CET1-w) was selected for further application with higher sensitivity. The average ROC-AUC, specificity, sensitivity of the SVM ensemble model in a 5-fold cross-validation and in the independent test set of 160 patients were 0.922, 0.922, 0.777 and 0.928, 0.915, 0.737, respectively. Moreover, for recurrent region segmentation, the multi-modality (T1-w+CET1-w) model was superior to the single-modality (T1-w or CET1-w) model. In an independent test set of 15 patients, the DSC, sensitivity and 95% Hausdorff Distance between actual and predicted GTVr was 0.549±0.176, 0.696±0.118 and 9.813±4.788 which was superior to 0.444±0.188, 0.497±0.218 and 12.047±5.361 of original 3D U-Net.

CONCLUSION

The proposed two-step radiomics workflow showed a good performance in predicting tumor recurrence of NPC. The predicted location of the recurrence lesion was all accurate, but there was still a certain difference between the volume of the automated delineated and actual GTVr, which needed to be further optimized to be used as biological tumor volume.

Prediction of Response to Neoadjuvant Chemoradiotherapy Combined with Pembrolizumab in Esophageal Squamous Cell Carcinoma with CT/FDG PET Radiomic Signatures Based on Machine Learning Classification

PURPOSE/OBJECTIVE(S)

PALACE-1 trial has confirm that the addition of pembrolizumab to neoadjuvant chemoradiotherapy (NCRT) improves the pathological complete response(pCR) for esophageal squamous cell carcinoma (ESCC), which might be a novel treatment strategy for ESCC. In the present study, we aim to establish a machine learning model to predict the local response to NCRT+ pembrolizumab for ESCC by using pretreatment 18-fluorodeoxyglucose positron emission tomography (FDG PET) and contrast-enhanced plan CT images.

MATERIALS/METHODS

A total of 65 cases treated with NCRT+ pembrolizumab followed by surgery were prospectively enrolled for analysis from 2019-2022. Each patient contains a contrast-enhanced plan CT and FDG PET images. 52 patients were randomly divided into training set and 13 patients were used as test set. The Extraction of radiomics features was performed using an open-source Python library PyRadiomics automatically. Features were computed according to the radiologist-drawn ROIs on both CT and PET images. In the feature selection stage least absolute shrinkage and selection operator (LASSO) was utilized on CT features and PET features separately. Four different machine learning models were implemented: Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF) and XGBoost (XGB). The features selected by LASSO regression were used as model input and the output of the model is "pCR" or "non-pCR". To find the optimal parameter, the 5-fold cross-validation method was used in the training stage. In this study, we use accuracy, sensitivity and specificity as the metrics to evaluate the performance of the model on the testing cohort. The predictive performance of the model was assessed using the area under curve (AUC) of the receiver operating characteristics curve (ROC).

RESULTS

Of the 65 cases treated with NCRT+pembrolizumab, 35 patients archived pCR (53.8%), and 30 archived non-pCR. 1684 radiomics features were extracted from each case, and half of them (842 features) were from CT and others were from PET. Among the machine learning models mentioned above SVM achieves the most promising performance on the evaluation metrics. Accuracy, sensitivity, specificity and AUC score on test set were 0.692, 0.833, 0.571 and 0.786 for CT features and 0.615, 0.667, 0.571 and 0.762 for PET features, respectively. For CT+FDG PET fused features accuracy, sensitivity, specificity and AUC score on test set were 0.769, 0.667, 0.857 and 0.833.

CONCLUSION

In this study, we performed several different machine learning models to predict the response to NCRT+ pembrolizumab among ESCC based on the extracted radiomics features from CT and FDG PET images. The best-performing model based on radiomics features of CT and PET images could identify non-pCR to NCRT + pembrolizumab in EC patients.

Foliar spray of La2O3 nanoparticles regulates the growth, antioxidant parameters, and nitrogen metabolism of fragrant rice seedlings in wet and dry nurseries

Nanoparticles (NPs) have been widely used in agriculture, and lanthanum oxide nanoparticles (La2O3) NPs can regulate plant growth. La2O3 NPs treatment was hypothesized to affect the accumulation and distribution of substances in rice seedlings under wet and dry nursery conditions. The objective of the present study was to ascertain the effects of La2O3 NPs foliar spray on the morphology and physiology of fragrant rice seedlings under wet and dry nursery conditions. Seedlings of two fragrant rice cultivars, namely 'Xiangyaxiangzhan' and 'Yuxiangyouzhan,' were grown under wet and dry nursery conditions with La2O3 NPs treatments at three concentrations (CK, La2O3 NPs 0 mg L-1; T1, La2O3 NPs 20 mg L-1; and T2, La2O3 NPs 40 mg L-1). The results showed that the seedling-raising method was significantly associated with La2O3 NPs application (P < 0.05), affecting the leaf area of both cultivars. Changes in plant morphological parameters, such as dry weight and root-shoot ratio, were the reasons for the differences in cultivars in response to La2O3 NPs application. Changes were also observed in the plant morphological and physiological parameters of leaf area, specific leaf area, chlorophyll contents, antioxidant properties, and activities of nitrogen metabolism enzymes. The relationship between morphological and physiological processes in fragrant rice was investigated to test the hypothesis. In both wet and dry nursery methods, the T2 concentration of La2O3 NPs was beneficial for rice seedlings and significantly increased their leaf area due to changes in morphological and physiological parameters. Therefore, the results of this study provide a theoretical basis for expanding the research on La2O3 NPs application in rice, as well as relevant references for strengthening rice seedlings in the nursery, which has a positive effect on the grain yield improvement in fragrant rice.

Exogenous TiO2 Nanoparticles Alleviate Cd Toxicity by Reducing Cd Uptake and Regulating Plant Physiological Activity and Antioxidant Defense Systems in Rice (Oryza sativa L.)

Cadmium (Cd) is a potentially hazardous element with significant biological toxicity, negatively affecting plant growth and physio-biochemical metabolism. Thus, it is necessary to examine practical and eco-friendly approaches to reduce Cd toxicity. Titanium dioxide nanoparticles (TiO₂-NPs) are growth regulators that help in nutrient uptake and improve plant defense systems against abiotic and biological stress. A pot experiment was performed in the late rice-growing season (July-November) 2022 to explore the role of TiO₂-NPs in relieving Cd toxicity on leaf physiological activity, biochemical attributes, and plant antioxidant defense systems of two different fragrant rice cultivars, i.e., Xiangyaxiangzhan (XGZ) and Meixiangzhan-2 (MXZ-2). Both cultivars were cultivated under normal and Cd-stress conditions. Different doses of TiO₂-NPs with and without Cd-stress conditions were studied. The treatment combinations were: Cd-, 0 mg/kg CdCl₂·2.5 H₂O; Cd+, 50 mg/kg CdCl₂·2.5 H₂O; Cd + NP1, 50 mg/kg Cd + 50 TiO₂-NPs mg/L; Cd + NP2, 50 mg/kg Cd + 100 TiO₂-NPs mg/L; Cd + NP3, 50 mg/kg Cd + 200 TiO₂-NPs mg/L; Cd + NP4, 50 mg/kg Cd + 400 TiO₂-NPs mg/L. Our results showed that the Cd stress significantly (p < 0.05) decreased leaf photosynthetic efficiency, stomatal traits, antioxidant enzyme activities, and the expression of their encoding genes and protein content. Moreover, Cd toxicity destabilized plant metabolism owing to greater accretion of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels at vegetative and reproductive stages. However, TiO₂-NPs application improved leaf photosynthetic efficacy, stomatal traits, and protein and antioxidant enzyme activities under Cd toxicity. Application of TiO₂-NPs decreased the uptake and accumulation of Cd in plants and levels of H₂O₂ and MDA, thereby helping to relieve Cd-induced peroxidation damage of leaf membrane lipids by enhancing the activities of different enzymes like ascorbate peroxidase (APX), catalase (CAT), peroxidase (POS), and superoxide dismutase (SOD). Average increases in SOD, APX, CAT, and POS activities of 120.5 and 110.4%, 116.2 and 123.4%, 41.4 and 43.8%, and 36.6 and 34.2% in MXZ-2 and XGZ, respectively, were noted in Cd + NP3 treatment across the growth stages as compared with Cd-stressed plants without NPs. Moreover, the correlation analysis revealed that the leaf net photosynthetic rate is strongly associated with leaf proline and soluble protein content, suggesting that a higher net photosynthetic rate results in higher leaf proline and soluble protein content. Of the treatments, the Cd + NP3 (50 mg/kg Cd + 200 mg/L TiO₂-NPs) performed the best for both fragrant rice cultivars under Cd toxicity. Our results showed that TiO₂-NPs strengthened rice metabolism through an enhanced antioxidant defense system across the growth stages, thereby improving plant physiological activity and biochemical characteristics under Cd toxicity.

Nitric oxide confers cadmium tolerance in fragrant rice by modulating physio-biochemical processes, yield attributes, and grain quality traits

Cadmium (Cd) stress causes serious disruptions in plant metabolism, physio-biochemical processes, crop yield, and quality characters. Nitric oxide (NO) improves the quality features and nutritional contents of fruit plants. However, how NO confers Cd toxicity in fragrant rice plants, is sparse. Hence, the present study investigated the effects of 50 µM NO donor sodium nitroprusside (SNP) on physio-biochemical processes, plant growth attributes, grain yield, and quality traits of fragrant rice under Cd stress (100 mg kg^-1 soil). The results revealed that Cd stress diminished rice plant growth, impaired photosynthetic apparatus and antioxidant defense system, and deteriorated the grain quality traits. However, foliar application of SNP mitigated Cd stress by improving plant growth and gas exchange attributes. Higher electrolyte leakage (EL) was accompanied with elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) under Cd stress; however, exogenous application of SNP reduced them. The activities and relative expression levels of enzymatic antioxidants; superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants, glutathione (GSH) contents were reduced by Cd stress, while SNP application regulated their activity and transcript abundances. SNP application improved fragrant rice grain yield and 2-acetyl-1-pyrroline content by 57.68 % and 75.54 % respectively, which is concomitant with higher biomass accumulation, photosynthetic efficiency, photosynthetic pigment contents, and an improved antioxidant defense system. Collectively, our results concluded that SNP application regulated the fragrant rice plant physio-biochemical processes, yield traits and grain quality characters under Cd-affected soil.

Biosynthesis of 2-Acetyl-1-pyrroline in Fragrant Rice: Recent Insights into Agro-management, Environmental Factors, and Functional Genomics

Rice is a staple food for more than half of the world's population, and rice fragrance is a key quality attribute which is highly desired by consumers and attracts premium prices in the international market. There are around 200 volatile compounds involved in rice fragrance, but 2-acetyl-1-pyrroline (2-AP) has been considered a master regulator of aroma in fragrant rice. Consequently, efforts were made to increase the 2-AP contents in the grain by managing agronomical practices or by using modern functional genomic tools, which successfully converted nonfragrant cultivars to fragrant rice. Furthermore, environmental factors were also reported to influence the 2-AP contents. However, a comprehensive analysis of 2-AP biosynthesis in response to agro-management practices, environmental factors, and the application of functional genomic tools for fragrant rice production was missing. In this Review, we summarize how micro/macronutrients, cultivation practices, amino acid precursors, growth regulators, and environmental factors, such as drought, salinity, light, and temperature, influence the 2-AP biosynthesis to modulate the aroma of fragrant rice. Furthermore, we also summarized the successful conversion of nonfragrant rice cultivars to fragrant rice using modern gene editing tools, such as RNAi, TALENS, and CRISPR-Cas9. Finally, we discussed and highlighted the future perspective and challenges related to the aroma of fragrant rice.

Alternate wetting and drying modulated physio-biochemical attributes, grain yield, quality, and aroma volatile in fragrant rice

Alternate wetting and drying (AWD) has been recognized as a water-saving technology in rice production systems; however, pre- and post-flowering AWD could induce changes in yield, quality and aroma biosynthesis in fragrant rice. In the present study, two fragrant rice cultivars (Guixiangzhan and Nongxiang-18) were subjected to AWD till soil water potential reached -25 to -30 kPa during vegetative stage (VS), reproductive stage (RS), and both stages (VS + RS). The AWD did not affect net photosynthesis and gas exchange significantly, while malondialdehyde (MDA), H₂ O₂ and electrolyte leakage (EL) were higher than in control plants. The AWD treatments variably affected soluble sugars, proline and protein accumulation as well as the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and reduced glutathione (GSH) contents. Moreover, filled grain percentage and 1000-grain weight in AWD treatments were found to be statistically similar (p > 0.05) to control, except grains panicle^-1 under AWD-VS + RS that was reduced by 11% and 14% for Guixiangzhan and Nongxiang-18, respectively. On average, yield and related attributes in Guixiangzhan remained higher than in Nongxiang-18. In addition, the grain aroma volatile (2-acetyl-1-pyrroline, 2-AP) content increased by 8.79%, 14.45%, and 6.87% and 7.95%, 14.02%, and 5.04% under AWD-VS, AWD-RS, and AWD-VS + RS treatments, for Guixiangzhan and Nongxiang-18, respectively. Overall, AWD treatments, either at VS or RS, could promote rice aroma in terms of accumulation of 2AP, which might be linked with enhanced endogenous proline contents (a precursor for 2AP biosynthesis) without any severe consequences on rice yield and quality.

Nitrogen modulates early growth and physio-biochemical attributes in fragrant rice grown under cadmium and multiwall carbon nanotubes stresses

Nitrogen (N) modulates plant growth, but its impact on the early growth and physio-biochemical characteristics of rice under cadmium (Cd) and multiwall carbon nanotubes (MWCNTs) toxicity has received little attention. In this study, a hydroponic experiment was conducted on two fragrant rice cultivars, e.g., Xiangyaxiangzhan (XYXZ) and Yuxiangyouzhan (YXYZ), grown under two N levels (N and 1/4 N) and various Cd and MWCNTs treatments (CK: without CdCl₂ or MWCNTs; Cd: 100 μmol L^-1 CdCl₂; MWCNTs: 100 mg L^-1 MWCNTs; and Cd-MWCNTs: 100 μmol L^-1 CdCl₂ + 100 mg L^-1 MWCNTs). Results showed that when compared to CK, the total dry weight of the Cd and MWCNTs treatments did not change under 1/4 N for both varieties, whereas Cd and Cd-MWCNTs treatments resulted in a significant reduction in total dry weight by 18.78-37.85% for XYXZ and the Cd-MWCNTs treatment resulted in a significant reduction in the total dry weight by 20.24% for YXYZ. The changes in total dry weight were linked to changes in the dry weight of the different parts of the plant. Besides, the antioxidant parameters and the enzymes involved in the nitrogen metabolism changed in different varieties and different plant parts under two N levels and various Cd and MWCNTs treatments. In addition, differences in total dry weight changes at the N levels and various Cd and MWCNTs treatments were identified between the two varieties, and the relations between total dry weight and other investigated parameters indicated that the modulation processes varied between varieties. Overall, N modulates the early growth and physio-biochemical attributes in fragrant rice seedlings under Cd, MWCNTs, and their combined toxicity.

Post-transcriptional regulation of 2-acetyl-1-pyrroline (2-AP) biosynthesis pathway, silicon, and heavy metal transporters in response to Zn in fragrant rice

Fragrant rice (Oryza sativa L.) has a high economic and nutritional value, and the application of micronutrients regulates 2-acetyl-1-pyrroline (2-AP) production, which is responsible for aroma in fragrant rice. Alternative splicing (AS) is an important post-transcriptional regulatory mechanism to generate transcript variability and proteome diversity in plants. However, no systematic investigation of AS events in response to micronutrients (Zn) has been performed in fragrant rice. Furthermore, the post-transcriptional regulation of genes involved in 2-AP biosynthesis is also not known. In this study, a comprehensive analysis of AS events under two gradients of Zn treatment in two different fragrant rice cultivars (Meixiangzhan-2 and Xiangyaxiangzhan) was performed based on RNA-seq analysis. A total of 386 and 598 significant AS events were found in Meixiangzhan-2 treated with low and high doses of Zn, respectively. In Xiangyaxiangzhan, a total of 449 and 598 significant AS events were found in low and high doses of Zn, respectively. Go analysis indicated that these genes were highly enriched in physiological processes, metabolism, and cellular processes in both cultivars. However, genotype and dose-dependent AS events were also detected in both cultivars. By comparing differential AS (DAS) events with differentially expressed genes (DEGs), we found a weak overlap among DAS and DEGs in both fragrant rice cultivars indicating that only a few genes are post-transcriptionally regulated in response to Zn treatment. We further report that Zn differentially regulates the expression of 2-AP biosynthesis-related genes in both cultivars and Zn treatment altered the editing frequency of single nucleotide polymorphism (SNPs) in the genes involved in 2-AP biosynthesis. Finally, we showed that epigenetic modifications associated with active gene transcription are generally enriched over 2-AP biosynthesis-related genes. Similar to the 2-AP pathway, we found that heavy metal transporters (genes related to silicon, iron, Zn and other metal transport) are also regulated at transcriptional and post-transcriptional levels in response to Zn in fragrant rice. Taken together, our results provide evidence of the post-transcriptional gene regulation in fragrant rice in response to Zn treatment and highlight that the 2-AP biosynthesis pathway and heavy metal transporters may also be regulated through epigenetic modifications. These findings will serve as a cornerstone for further investigation to understand the molecular mechanisms of 2-AP biosynthesis and regulation of heavy metal transporters in fragrant rice.

Zinc oxide nanoparticles and polyethylene microplastics affect the growth, physiological and biochemical attributes, and Zn accumulation of rice seedlings

Metal nanoparticles and microplastics are becoming important pollutants in agricultural fields, but there are few studies on the interaction of zinc oxide nanoparticles (ZnONPs) and polyethylene (PE) microplastics with rice seedlings. The two rice cultivars Xiangyaxiangzhan and Yuxiangyouzhan were grown at three ZnONP levels (0 mg L^-1, 50 mg L^-1, and 500 mg L^-1) and three PE levels (0 mg L^-1, 250 mg L^-1, and 500 mg L^-1), and the growth, physiological attributes, and Zn uptake of rice seedlings were measured. Result showed that the ZnONPs and PE treatment effects on the investigated parameters differed between the cultivars, whilst Yuxiangyouzhan produced 6.98% higher in mean total dry biomass than Xiangyaxiangzhan. The mean total dry biomass in Xiangyaxiagnzhan and Yuxiangyouzhan changed by 10.22-30.85% and - 11.74-25.58% under ZnONPs, respectively. The PE treatments reduced growth parameters in Xiangyaxiangzhan, whilst the 250 mg L^-1 PE treatment reduced the growth parameter of Yuxiangyouzhan. Besides, the ZnONP treatment had a stronger effect on rice seedling growth than the PE treatment. Furthermore, the ZnONPs modulated the physiological parameter in plant tissue of the two rice varieties. ZnONP treatment lead to the accumulation of Zn in plant tissue and the shoot Zn content was strongly related to shoot cellulose content. Overall, ZnONPs and PE treatments modulated the growth, physiological and biochemical attributes, and Zn uptake of rice seedlings, and the cultivars and dose effects could not be ignored.

Exogenous Gamma-Aminobutyric Acid Application Induced Modulations in the Performance of Aromatic Rice Under Lead Toxicity

Gamma-aminobutyric acid (GABA) is a non-protein amino acid and has a multi-functional role in abiotic stress tolerance. A pot experiment was conducted to assess the role of exogenous gamma-aminobutyric acid (GABA) application to modulate the growth, yield, and related physio-biochemical mechanisms in two aromatic rice cultivars, that is, Guixiangzhan (GXZ) and Nongxiang 18 (NX-18), under Pb toxic and normal conditions. The experimental treatments were comprised of Ck: without Pb and GABA (control), GABA: 1 mM GABA is applied under normal conditions (without Pb), Pb + GABA: 1 mM GABA is applied under Pb toxicity (800 mg kg^-1 of soil), and Pb= only Pb (800 mg kg^-1 of soil) is applied (no GABA). The required concentrations of GABA were applied as a foliar spray. Results revealed that Pb stress induced oxidative damage in terms of enhanced malondialdehyde (MDA), electrolyte leakage (EL), and H₂O₂ contents, while exogenous GABA application improved leaf chlorophyll, proline, protein and GABA contents, photosynthesis and gas exchange, and antioxidant defense under Pb toxicity in both rice cultivars. Moreover, glutamine synthetase (GS) and nitrate reductase (NR) activities were variably affected due to GABA application under Pb stress. The yield and related traits, that is, productive tillers/pot, grains/panicle, filled grain %, 1,000-grain weight, and grain yield were 13.64 and 10.29, 0.37% and 2.26%, 3.89 and 19.06%, 7.35 and 12.84%, and 17.92 and 40.56 lower under Pb treatment than Pb + GABA for GXZ and NX-18, respectively. Furthermore, exogenous GABA application in rice reduced Pb contents in shoot, leaves, panicle, and grains compared with Pb-exposed plants without GABA. Overall, GXZ performed better than NX-18 under Pb toxic conditions.

Radiocesium distribution caused by tillage inversion affects the soil-to-crop transfer factor and translocation in agroecosystems

This study reports the translocation of cesium-137 (¹³⁷Cs) into deep soil layers, and the ¹³⁷Cs transfer from soil to soybean in farmland under three tillage (no tillage, NT; rotary cultivation, RC; moldboard plow; MP) treatments and an undisturbed grassland (GL) at eight years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on 11 March 2011 in Japan. Tillage influences the ¹³⁷Cs distribution in the 0-30 cm of soil; the distribution of ¹³⁷Cs in the soil was uniform under RC and MP treatments, while in the grassland, most ¹³⁷Cs was concentrated on the soil surface (0-2.5 cm). The center of vertical ¹³⁷Cs radioactivity concentration (the thickness of the soil from surface which containing half of the ¹³⁷Cs inventory) in GL was 5.5 cm, which was shallower than that in farmland (9.5 cm in NT, 13.6 cm in RC and 15.2 cm in MP). Hence, the total translocation distance of ¹³⁷Cs 8 years after FDNPP accident showed the following trend: GL (2.4 cm) < NT (7.0 cm) < RC (10.0 cm) < MP (12.3 cm). Meanwhile, a significant positive correlation was observed between ¹³⁷Cs radioactivity concentration and organic carbon and nitrogen content in the soil. However, the ¹³⁷Cs radioactivity concentration in soybean grains was negatively correlated with the center of vertical ¹³⁷Cs radioactivity concentration but positively correlated with the ratio of exchangeable ¹³⁷Cs (ExCs) and K content in the soil. The ExCs/K and ¹³⁷Cs distributions in the soil were combined into a statistical model to predict the ¹³⁷Cs radioactivity concentration in soybean grain. The results revealed the magnitude of the impact of ¹³⁷Cs distribution on the ¹³⁷Cs transfer from soil to crop. The addition of the ¹³⁷Cs distribution dramatically improved the accuracy of the prediction model of ¹³⁷Cs radioactivity concentration in soybean.

[VIPR1 promoter methylation promotes transcription factor AP-2α binding to inhibit VIPR1 expression and promote hepatocellular carcinoma cell growth in vitro]

OBJECTIVE

To explore the transcriptional regulation mechanism and biological function of low expression of vasoactive intestinal peptide receptor 1 (VIPR1) in hepatocellular carcinoma (HCC).

METHODS

We constructed plasmids carrying wild-type VIPR1 promoter or two mutant VIPR1 promoter sequences for transfection of the HCC cell lines Hep3B and Huh7, and examined the effect of AP-2α expression on VIPR1 promoter activity using dual-luciferase reporter assay. Pyrosequencing was performed to detect the changes in VIPR1 promoter methylation level in HCC cells treated with a DNA methyltransferase inhibitor (DAC). Chromatin immunoprecipitation was used to evaluate the binding ability of AP-2α to VIPR1 promoter. Western blotting was used to assess the effect of AP-2α knockdown on VIPR1 expression and examine the differential expression of VIPR1 in the two cell lines. The effects of VIPR1 overexpression and knockdown on the proliferation, cell cycle and apoptosis of HCC cells were analyzed using CCK8 assay and flow cytometry. We also observed the growth of HCC xenograft with lentivirus-mediated over-expression of VIPR1 in nude mice.

RESULTS

Compared with the wild-type VIPR1 promoter group, co-transfection with the vector carrying two promoter mutations and the AP-2α-over-expressing plasmid obviously restored the luciferase activity in HCC cells (P < 0.05). DAC treatment of the cells significantly decreased the methylation level of VIPR1 promoter and inhibited the binding of AP-2α to VIPR1 promoter (P < 0.01). The HCC cells with AP-2α knockdown showed increased VIPR1 expression, which was lower in Huh7 cells than in Hep3B cells. VIPR1 overexpression in HCC cells caused significant cell cycle arrest in G2/M phase (P < 0.01), promoted cell apoptosis (P < 0.001), and inhibited cell proliferation (P < 0.001), while VIPR1 knockdown produced the opposite effects. In the tumor-bearing nude mice, VIPR1 overexpression in the HCC cells significantly suppressed the increase of tumor volume (P < 0.001) and weight (P < 0.05).

CONCLUSION

VIPR1 promoter methylation in HCC promotes the binding of AP-2α and inhibits VIPR1 expression, while VIPR1 overexpression causes cell cycle arrest, promotes cell apoptosis, and inhibits cell proliferation and tumor growth.

Water and Nitrogen Management at the Booting Stage Affects Yield, Grain Quality, Nutrient Uptake, and Use Efficiency of Fragrant Rice Under the Agro-Climatic Conditions of South China

The present study was conducted to assess the effects of water and nitrogen applications at the booting stage on yield, grain quality, and nutrient use efficiencies in fragrant rice in the early (March-July) and late (July-November) seasons of 2013. The experiment was comprised of two fragrant rice cultivars, i.e., Nongxiang 18 and Basmati; three nitrogen levels, i.e., 0 kg N ha^-1 (N0), 30 kg N ha^-1 (N1), and 60 kg N ha^-1 (N2); and three water levels, i.e., 2-4 cm water layer well-watered (W0), water with a soil water potential of -15 ± 5 kPa (W1), and water with a soil water potential of -25 ± 5 kPa (W2), which were randomized in a split-split plot design. Results showed that Basmati produced a higher grain yield than Nongxiang 18 (16.20 and 9.61% in the early and late season, respectively), whereas the W1 exhibited the maximum grain yield and harvest index. The moderate application of nitrogen (N1) at the booting stage resulted in higher grain yield, nevertheless, cultivar, water, and nitrogen revealed different trends for some of the grain quality attributes, i.e., brown rice rate, milled rice rate, head milled rice rate, protein content, and amylose content as well as nutrient uptake and use efficiencies in the double rice production system. Basmati had a higher nitrogen harvest index (NHI; 18.28-20.23%) and P harvest index (PHI; 3.95-12.42%) but lower physiological P use efficiency for biomass (PPUEB; 7.66-23.66%) and physiological K use efficiency for biomass (PKUEB; 2.53-7.10%) than Nongxiang 18 in both seasons. Furthermore, the grain number per panicle, biomass yield, grain P uptake, and the whole plant P uptake were significantly related to the grain yield of fragrant rice. In both seasons, the interaction of water and nitrogen (W × N) had a significant effect on panicle number, grain quality attributes, and N, P uptake of straw, as well as the physiological N, P use efficiency for grain and the physiological N, K use efficiency for biomass. Overall, results suggest that moderate nitrogen and irrigation input at the booting stage could be feasible to improve the productivity and quality of the double rice production system with improved nutrient use efficiency under the agro-climatic conditions of South China.

Transcriptional cascades in the regulation of 2-AP biosynthesis under Zn supply in fragrant rice

Transcription factors (TFs) regulate gene expression to control certain genetic programs, such as growth and development, phytohormone regulation, and environmental stresses. 2-acetyl-1-pyrroline (2-AP) is the key element involved in aroma biosynthesis pathway, and the application of micronutrients can increase the 2-AP levels. However, little is known about the micronutrient-induced TFs involved in 2-AP biosynthesis. Here, we identify a number of TF families in two fragrant rice varieties, "Meixiangzhan-2" (M) and "Xiangyaxiangzhan" (X), in response to Zinc (Zn) application through transcriptomic analysis. A total of ~678 TFs were identified and grouped into 26 TF families, each of which was found to be involved in numerous signaling pathways. The WRKY TF family was found to be the most abundant, followed by bHLH and MYB. Furthermore, members of the WRKY, bHLH, MYB, ERF, HSF, MADS-box, NFY, and AP2 TF families were significantly upregulated and may be involved in the transcriptional regulation of aroma biosynthesis. In brief, this study enhances our understanding of the molecular mechanism of 2-AP biosynthesis and highlights the key TFs potentially involved in the production of aroma in fragrant rice.

Effect of Exogenous Melatonin Application on the Grain Yield and Antioxidant Capacity in Aromatic Rice under Combined Lead–Cadmium Stress

This study aimed to determine the mechanism of exogenous melatonin application in alleviating the combined Pb and Cd (Pb-Cd) toxicity on aromatic rice (Oryza sativa L.). In this study, a pot experiment was conducted; two aromatic rice varieties, Yuxiangyouzhan and Xiangyaxiangzhan, were selected, and sprays using 50, 100, 200, and 400 μmol L−1 melatonin (denoted as S50, S100, S200, and S400) and irrigation using 100, 300, and 500 μmol L−1 melatonin (denoted as R100, R300, and R500) were also selected. The results showed that, under the S50, S100, and S200 treatments, the Pb content of aromatic rice grain decreased, and the grain yield increased significantly. Moreover, the application of exogenous melatonin significantly reduced the accumulation of H2O2 in rice leaves at maturity under Cd–Pb stress and reduced the MDA content in Xiangyaxiangzhan leaves. In addition, the microbial community structure changed significantly under S50 and R300 treatments. Some pathways, such as the synthesis of various amino acids and alanine, aspartate, and glutamate metabolism, were regulated by S50 treatment. Overall, melatonin application improved aromatic rice grain yield while reducing heavy metal accumulation by regulating the antioxidant capacity and metabolites in aromatic rice plants and altering the physicochemical properties and microbial community structures of the soil.

Application of hydrogen-rich water modulates physio-biochemical functions and early growth of fragrant rice under Cd and Pb stress

Application of hydrogen-rich water (HRW) could improve plant growth under stress conditions; however, its effects on early growth and related physiological functions of fragrant rice under cadmium (Cd) and lead (Pb) toxicity are unknown. The present study was composed of two HRW treatments, i.e., H0: without H₂ and HRW: with 500ppb H₂ gas, three treatments with two metals, i.e., M0: without heavy metal, Cd: 75 μmol l^-1 of Cd, Pb: 750 μmol l^-1 of Pb applied to two popular fragrant rice cultivars, i.e., Yuxiangyouzhan and Xiangyaxiangzhan. The growth and physio-biochemical attributes of fragrant rice at 5 and 10 days after treatment (DAT) were assessed. Results showed that HRW treatment promoted the growth of rice seedlings in terms of increased dry biomass of shoot, root, and the whole seedling at 10 DAT. Moreover, HRW also improved early growth of fragrant rice under Pb stress with substantial increase in fresh and dry weight of roots and the whole seedling at 5 and 10 DAT. Application of HRW slightly alleviated the root inhibition caused by Cd toxicity in rice seedlings at 10 DAT. In addition, antioxidant activities, i.e., catalase (CAT) and peroxidase (POD), were increased with HRW application at 10 DAT while decreased root Pb and Cd contents of both rice cultivars. Overall, HRW alleviated the inhibitory effects of Cd and Pb toxicity by regulating the antioxidant defense response in growing rice plants.

Ultrasonic seed treatment improved morpho-physiological and yield traits and reduced grain Cd concentrations in rice

Rice cultivation under cadmium (Cd) contaminated soil often results in reduced growth with excess grain Cd concentrations. A pot experiment was conducted to assess the potential of ultrasonic seed treatment to alleviate Cd stress in rice. Seeds of two aromatic rice cultivars i.e., Xiangyaxiangzhan and Meixiangzhan 2 and two non-aromatic rice cultivars i.e., Huahang 31 and Guangyan 1 were exposed to ultrasonic waves for 1.5 min in 20-40 KHz mixing frequency. The experimental treatments were comprised of untreated seeds (U0) and ultrasonic treated seeds (U1) transplanted in un-contaminated soil (H0) and Cd-contaminated soil (H1). Results revealed that Cd contents and Cd accumulation in grain in U1 were 33.33-42.31% and 12.86-57.58% lower than U0 for fragrant rice cultivars under H1. Meanwhile, biomass production was higher in U1 than U0 under H0 and better yield was assessed in U1 for all cultivars under H1. The activity of peroxidase (POD) in flag leaves was increased by 8.28-115.65% for all cultivars while malondialdehyde (MDA) contents were significantly decreased in U1 compared with U0 under H0. Conclusively, ultrasonic treatment modulated Cd distribution and accumulation in different parts while improved physiological performance as well as yield and grain quality of rice under Cd contaminated conditions.

Application of γ-aminobutyric acid under low light conditions: Effects on yield, aroma, element status, and physiological attributes of fragrant rice

Cloudy weather with low light is more common during rice growing season of South China which often leads reduced yield and aroma formations in fragrant rice. However, exogenous γ-aminobutyric acid (GABA) application could enhance the 2-acetyl-1-pyrroline (2AP) accumulations and yield of fragrant rice under low light conditions. Field and pot experiments were conducted with three fragrant rice cultivars i.e., Basmati and Yuxiangyouzhan (indica), and Yungengyou 14 (japonica) that were grown under three different treatments i.e., normal light + GABA 0 mg L^-1 (CK), low light + GABA 0 mg L^-1 (T1), and low light + GABA 250 mg L^-1 (T2). The results revealed that the grain 2AP contents were increased by 14.67-34.83% and up to 29.34% under T1 and T2 treatments in pot and field experiments, respectively, as compared with CK. The T1 and T2 treatments improved aroma owing to regulation in the accumulation of micronutrients i.e., Na, Mn, and Fe and enzyme activities involved in 2AP biosynthesis. The grain yield was substantially reduced in T1 as compared with T2 treatment for all rice cultivars. On the other hand, GABA application improved the grain yield under low light conditions by regulating the plant growth, and related physiological and biochemical attributes in all rice cultivars. Thus, GABA could balance low light-induced 2AP content and grain yield by modulating morphological and yield related attributes as well as physio-biochemical responses of fragrant rice.

ZnO nanoparticle-based seed priming modulates early growth and enhances physio-biochemical and metabolic profiles of fragrant rice against cadmium toxicity

Background

Cadmium (Cd) is amongst the most toxic heavy metals that severely affects crop growth, whereas application of nanoparticles (NPs) to negate the toxic effects of heavy metals could be an effective management approach. In the present study, the seeds of two fragrant rice varieties i.e., Yuxiangyouzhan and Xiangyaxiangzhan under normal and Cd stress conditions i.e., 0 and 100 mg L^− 1 applied with four levels of ZnO NPs i.e., 0, 25, 50, and 100 mg L^− 1.

Results

Seed priming with ZnO NPs had no significant effect on the seed germination (p > 0.05) however, it substantially improved the seedling growth and other related physiological attributes under the Cd stress. The mean fresh weight of the shoot, and whole seedling was increased by 16.92–27.88% and by 16.92–27.88% after ZnO NPs application. The root fresh weight, root-shoot length was also substantially improved under ZnO NPs treatment. Moreover, application of ZnO NPs induced modulations in physiological and biochemical attributes e.g., the superoxide dismutase (SOD) activity in root and shoot, the peroxidase (POD) activity and metallothionein contents in root were increased under low levels of ZnO NPs. The α-amylase and total amylase activity were improved by ZnO NPs application under Cd Stress. Besides, modulation in Zn concentration and ZnO NPs uptake in the seedling were detected. The metabolomic analysis indicated that various pathways such as alanine, aspartate and glutamate metabolism, phenylpropanoid biosynthesis, and taurine and hypotaurine metabolism were possibly important for rice response to ZnO NPs and Cd.

Conclusion

Overall, application of ZnO NPs substantially improved the early growth and related physio-biochemical attributes in rice. Our findings provide new insights regarding the effects of ZnO NPs on seed germination, and early growth of rice, and its potential applications in developing crop resilience against Cd contaminated soils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00820-9.

Differential response of fragrant rice cultivars to salinity and hydrogen rich water in relation to growth and antioxidative defense mechanisms

Salinity negatively effects the growth and productivity of crop plants; however, the effects of hydrogen rich water (HRW) on the early growth of fragrant rice under salinity stress are rarely investigated. In present study, two HRW treatments: foliar application (F-HRW) and irrigation (I-HRW) were applied on the two fragrant rice cultivars, Yuxiangyouzhan and Xiangyaxiangzhan, grown under normal and salt stress conditions, i.e., 0 and 150 mmol NaCl L^-1, respectively. Plants without HRW application were grown as control (CK). Results showed that the dry weight per unit plant height (mg cm^-1) was increased by 12.6% and 23.0% in F-HRW and I-HRW, respectively under salt stress as compared with CK. Application of HRW, regardless of the application method, modulated the antioxidant activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) while reduced malondialdehyde (MDA) contents under salt stress. Moreover, significant and positive relations were observed among total dry weight and shoot dry weight, dry weight per unit plant height, SOD and CAT activity in root. Overall, F-HRW application modulated the early growth and related physiological attributes in fragrant rice under salt stress whereas I-HRW was found to mitigate salt stress. Novelty statement: Involvement of endogenous H₂ in plants for regulating various physiological functions is of great importance to stimulate and/or activate the antioxidant defense responses against oxidative stress; however, there is a lack of research in this aspect. The present study investigated the effects of hydrogen rich water (HRW) on the growth and physiological attributes of two fragrant rice cultivars grown under salt-stress. It was noteworthy to find that application of HRW either foliar application or irrigation improved the morphological characters, i.e., dry weight per unit plant height and enhanced the activities of antioxidants, i.e., peroxidase, superoxide dismutase and catalase whilst decreased the malonaldehyde content. Overall, the application of HRW modulates plant growth and physiological attributes in fragrant rice cultivars under salt-stress conditions. This study will be helpful in improving the early growth and/or stand establishment of fragrant rice nursery under saline conditions.

Cell wall thickness and the molecular mechanism of heterogeneous vancomycin-intermediate Staphylococcus aureus

Methicillin‐resistant Staphylococcus aureus (MRSA) with reduced sensitivity to vancomycin (VAN) has caused many clinical cases of VAN treatment failure, but the molecular mechanism underlying the reduced sensitivity to VAN is still unclear. We isolated a heterogeneous VAN‐intermediate Staphylococcus aureus (hVISA), which was also a MRSA strain with reduced sensitivity to VAN. To investigate the molecular mechanism underlying the reduced sensitivity to VAN exhibited by the hVISA strain, we compared the hVISA strain with a VAN‐sensitive MRSA strain, known as the N315 strain. The images captured by transmission electron microscopy showed that the cell wall of the hVISA strain was significantly thicker than that of the N315 strain (36·72 ± 1·04 nm vs 28·15 ± 1·25 nm, P < 0·05), and the results of real‐time quantitative PCR analysis suggested that the expression levels of the cell wall thickness related genes (glmS, vraR/S, sgtB, murZ and PBP4) of the hVISA strain were significantly higher than those of the N315 strain (P < 0·05). In conclusion, this study indicated that the upregulation of the expression of the genes related to cell wall synthesis might be the molecular mechanism underlying the cell wall thickening of the hVISA strain and might be related to its resistance to VAN.

Application of inorganic passivators reduced Cd contents in brown rice in oilseed rape-rice rotation under Cd contaminated soil

Immobilization of heavy metals by the application of chemical amendments is an eco-friendly, economical and effective method to remediate cadmium (Cd) -contaminated soils. Field experiments were conducted during 2016-2018 following oilseed rape-rice rotation with the application of inorganic passivators i.e., slaked lime (CaOH₂>95%) and sepiolite (SiO₂>50%, MgO>20%). The experimental treatments were comprised of: rice planting in winter fallow and without passivator (F-PA0); fallow with slaked lime (F-PA1); fallow with sepiolite (F-PA2); oilseed rape-rice rotation without passivator (R-PA0); rotation with slaked lime (R-PA1); and rotation with sepiolite (R-PA2). The slaked lime and sepiolite were applied after the harvest of rape at 2000 and 5000 kg ha^-1, respectively. Results revealed that the Cd contents were reduced by 47.44-49.03% in brown rice for F-PA2 and 9.54-42.66% in soil for R-PA2. The superoxide dismutase (SOD) activity was decreased by 10.65-17.98%, the malondialdehyde (MDA) contents were reduced by 28.57% whereas the proline content was decreased by 32.61% under R-PA2. In addition, the filled grain percentage was improved by 6.87% (F-PA2) and 3.70% (R-PA1), respectively. Overall, rice sown after oilseed rape gave better yields than sown after fallow fields while application of slaked lime and sepiolite as passivator could be a potential management option to grow crops in metal polluted soils.

Light and water treatment during the early grain filling stage regulates yield and aroma formation in aromatic rice

The effect of light and water on aromatic rice remain largely unclear. A pot experiment was conducted to investigate the influences of light-water treatments (CK: natural light and well-watered conditions, WS: natural light and water-stressed conditions, LL: low light and well-watered conditions, LL-WS: low light and water-stressed treatment) on yield and 2-acetyl-1-pyrroline (2AP) formation in aromatic rice. Compared with CK, the light-water treatments decreased grain yield (10.32–39.19%) due to reductions in the filled grain percentage and total dry weight, in the regulation of biomass distribution, and in the attributes of gas exchange and antioxidant response parameters. The 2AP content in grains increased in the LL treatment (5.08–16.32%) but decreased in the WS treatment compared with that in CK. The changes in 2AP were associated with changes in 2AP formation-related traits and element content. Low light and water stress led to yield declines in aromatic rice, but low light alleviated the decrease in 2AP content caused by water stress.

Response of rice genotypes with differential nitrate reductase-dependent NO synthesis to melatonin under ZnO nanoparticles' (NPs) stress

Nitrate reductase is a nitric oxide (NO) induced enzyme in plants, NO acts as a signaling molecule under ZnO NPs-induced stress whereas melatonin (N-acetyl-5-methoxytryptamine) could improve morpho-physiological attributes of plants under adverse conditions. In present study, seedlings of two rice genotypes differed regarding nitrate reductase activities i.e., transgenic 'NR' and wild type 'WT' were applied with two melatonin levels i.e., 0, 10 μΜ regarded as M0, M10, respectively and three levels of ZnO NPs i.e., 0, 50, 500 mg L^-1 regarded as ZnO NPs0, ZnO NPs50 and ZnO NPs500, respectively. Results revealed that melatonin application substantially increased the dry biomass accumulation of both rice genotypes under all ZnO NPs levels. The root growth, mineral absorption as well as the antioxidant responses were also improved by melatonin application under ZnO NPs stress. The interactive effects of melatonin and genotype on plant growth, antioxidant responses and mineral contents i.e., Zn, Na, Fe and Mn were also found significant under different ZnO NPs stress. Furthermore, total plant dry weight was significantly correlated with the leaf dry weight, root volume, catalase (CAT) activity in leaves, Na accumulation in stem sheath and Fe accumulation in root under both M0 and M10 treatments. Moreover, the comparative transcriptome analysis identified key genes which were responsible for melatonin and NO-induced modulations in plant growth under ZnO NPs stress. Overall, melatonin could improve the morphological growth of the rice plants by modulating root-shoot characteristics, antioxidant activities and mineral uptake in root and shoot of rice.

Selenium-silicon (Se-Si) induced modulations in physio-biochemical responses, grain yield, quality, aroma formation and lodging in fragrant rice

Fragrant rice is a high-valued quality rice type which is gaining much popularity over the globe due to its better cooking qualities and special aromatic characteristics. Selenium (Se) and silicon (Si) could improve the growth and yield of rice; however, the combine effects of Se and Si (Se-Si treatments) on rice grain quality, aroma and lodging in fragrant rice were rarely investigated. The pot and field experiments were conducted with two fragrant rice cultivars i.e., Xiangyaxiangzhan and Yuxiangyouzhan, grown under three Se levels i.e., 0, 120, and 240 mg kg^-1 of soil (for pot experiment) and 0, 300, and 600 kg ha^-1 (for field experiment) regarded as LSe, MSe and HSe, respectively and two Si levels i.e., 0 and 60 mg kg^-1 of soil (for pot experiment) and 0 and 150 kg ha^-1 (for field experiment) regarded as -Si and +Si, respectively. Results depicted that the Se-Si treatments regulated head rice yield, grain yield and yield related traits and the HSe+Si treatment sustainably improved the grain yield and head rice yield by regulating plant growth, antioxidant response and malondialdehyde (MDA) contents in fragrant rice. The Se-Si treatments also improved the grain 2AP contents owing to regulation in the proline, pyrroline-5-carboxylate (P5C) and γ-aminobutyric acid (GABA) contents. Besides, Se-Si treatments also regulated the grain quality attributes and influenced the plant Se contents. Moreover, the Si mitigated Se-induced lodging resulted from changes in the lodging parameters i.e., lodging index, fresh weight per tiller, pushing resistance force, plant height and bending moment. Overall, the Se and Si application improved the grain yield and regulated the dry weight accumulation, antioxidant attributes and quality attributes. Meanwhile, the Si application mitigated the negative effect of Se-induced lodging in fragrant rice.

Ultrasonic seed treatment improved cadmium (Cd) tolerance in Brassica napus L

Cadmium (Cd) affects crop growth and productivity by disrupting normal plant metabolism. To determinate whether ultrasonic (US) seed treatment can alleviate Cd stress in rape (Brassica napus L.), the seeds of two oilseed rape cultivars i.e., 'Youyanzao18' and 'Zaoshu104' were exposed to ultrasonic waves for 1 min at 20 KHz frequency. Seeds without US treatment were taken as control (CK). Results revealed that the germination rate of both cultivars was significantly (P < 0.05) higher in US treatment than CK only at 0 and 10 mg Cd L^-1. The shoot and root length of both cultivars were significantly higher in US treatment than CK at all Cd treatments except the root length of Youyanzao18 at 50 mg Cd L^-1. The fresh weight Youyanzao18 was significantly (P < 0.05) higher in US than CK except for Youyanzao18 at 25 mg Cd L^-1. Moreover, the superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities and the proline, glutathione (GSH), and soluble protein contents in Youyanzao18 were relatively higher in the US treatment than CK. The malondialdehyde (MDA) contents were prominently reduced in US treatment than CK. The pods per plant, seeds per pod and rapeseed yield were increased by 15.9, 11.4, and 16.4% in Youyanzao18 and 10.3, 9.5, and 11.5% in Zaoshu104, respectively in US treatment, compared to CK. Moreover, the contents of Cd in root, stem, leaf, rape pod shell, and rapeseeds were comparatively less in US treatment than CK whereas the Cd concentrations in different plant parts of both rape cultivars were recorded as: leaf ˃ root ˃ stem ˃ rape pod shell ˃ rapeseed. In sum, the US treatment improved the morphological growth and rapeseed yield whereas reduced the Cd accumulation in different plant parts of rapeseed under Cd contaminated soil.

Application of γ-aminobutyric acid (GABA) and nitrogen regulates aroma biochemistry in fragrant rice

The 2-acetyl-1-pyrroline (2AP) is a key aroma compound in fragrant rice. The present study assessed the γ-aminobutyric acid (GABA) and nitrogen (N) application induced regulations in the biochemical basis of rice aroma formation. Four N levels, that is, 0, 0.87, 1.75, and 2.61 g/pot, and two GABA treatments, that is, 0 mg/L (GABA0) and 250 mg/L (GABA250), were applied to three fragrant rice cultivars, that is, Yuxiangyouzhan, Yungengyou 14, and Basmati-385. Results showed that GABA250 increased 2AP, Na, Mn, Zn, and Fe contents by 8.44%, 10.95%, 25.70%, 11.14%, and 43.30%, respectively, under N treatments across cultivars. The GABA250 further enhanced the activities of proline dehydrogenase (PDH), ornithine aminotransferase (OAT) (both at 15 days after heading (d AH), and diamine oxidase (DAO) (at maturity) by 20.36%, 11.24%, and 17.71%, respectively. Significant interaction between GABA and N for Mn, Zn, and Fe contents in grains, proline content in leaves, GABA content in leaves at 15 d AH and maturity stage (MS), Δ1-pyrroline-5-carboxylic acid (P5C) contents in leaves at 15 d AH, and Δ1-pyrroline-5-carboxylate synthase (P5CS), PDH, and OAT activities in leaves at MS was noted. Moreover, the 2AP contents in grains at MS showed a significant and positive correlation with the proline contents in the leaves at 15d AH. In conclusion, GABA250 enhanced the 2AP, Na, Mn, Zn, and Fe contents, as well as the enzyme activities involved in 2AP biosynthesis. Exogenous GABA and N application improved the 2AP contents and nutrient uptake in fragrant rice.

Correction to: Nitrogen application and different water regimes at booting stage improved yield and 2-acetyl-1-pyrroline (2AP) formation in fragrant rice

It was highlighted that the original article (Mo et al. 2019) contained an error in Fig. 1f which revealed the biosynthesis pathway of 2AP. This Correction article shows the correct Fig. 1 and incorrect Fig. 1. The original article has been updated.

Nitrogen application and different water regimes at booting stage improved yield and 2-acetyl-1-pyrroline (2AP) formation in fragrant rice

BACKGROUND

Water (W) and nitrogen (N) management generally cause regulations in the 2-acetyl-1-pyrroline (2AP) accumulation in fragrant rice; nevertheless, the feasibility of such management strategies at booting stage in improving 2AP accumulation has not been examined in details.

METHODS

Field experiments were conducted in the early season (March-July) and repeated in the late season (July-November) in 2013. The treatments were applied urea (90 kg ha^- 1), calcium super phosphate (90 kg ha^- 1) and potassium chloride (195 kg ha^- 1) as basal fertilizer, and urea (65 kg ha^- 1) at tillering stage. Three N levels i.e., 0 kg N ha^- 1 (N1), 30 kg N ha^- 1 (N2), and 60 kg N ha^- 1 (N3) and three water levels i.e., W1 treatment (well-watered treatment with water layer of 2-4 cm), W2 treatment (soil water potential was - 15 ± 5 kPa), and W3 treatment (soil water potential was - 25 ± 5 kPa) at booting stage was set up for three rice varieties i.e., Nongxiang 18, Yungengyou 14 and Basmati. The grain yield, head milled rice yield, 2AP contents and the biochemical parameters related to 2AP formation were investigated.

RESULTS

Result indicated that W and N dynamics regulated the grain yield, head milled rice yield, and 2AP contents in brown rice across three varieties. The N2 and N3 treatment significantly increased the 2AP contents in brown rice by 9.54% and 11.95%, and 8.88% and 32.54% in the early and the late season, respectively; improved grain yield and head milled rice yield. The W3 treatment improved grain yield, head milled rice yield and 2AP content. Significant W and N interaction effect on 2AP content in brown rice was detected, where the W3 N3 treatment showed the strongest interaction regarding improvement of 2AP contents in brown rice. The 2AP accumulation and its related biochemical parameters and their relationships in different plant tissues at different growth stages under W and N treatments had also been assessed. The 2AP content, P5C content and DAO activity during grain filling periods was highly related to the 2AP content in brown rice.

CONCLUSION

This study revealed that the 60 kg N ha^- 1 coupled with - 25 ± 5 kPa treatment showed the best positive effects on yield and aroma in fragrant rice, suggested that water and nitrogen management at booting stage can improve grain yield and fragrance in fragrant rice. However, further study to evaluate the metabolic and molecular basis of 2AP accumulation in fragrant rice is needed.

Calcium amendment improved the performance of fragrant rice and reduced metal uptake under cadmium toxicity

Cadmium (Cd) toxicity has detrimental effects on plant metabolism and yield formation. This study examined the effects of Cd stress in rice and the possible role of calcium (Ca) in mitigating oxidative damage caused by Cd in two fragrant rice cultivars, i.e., Guixiangzhan and Meixiangzhan 2. The experimental treatments were composed of various Ca and Cd levels as individual, i.e., Ca at 2.5 and 5.0 mg/kg soil (Ca1 and Ca2, respectively), Cd at 50 and 100 mg/kg soil (Cd50 and Cd100, respectively), and combined, i.e., Ca1+Cd50, Ca1+Cd100, Ca2+Cd50, and Ca2+Cd100. Plants without Ca and Cd application were taken as control (CK). Results showed that Cd stress led to a substantial decline in the photosynthetic pigments, i.e., Chl a, Chl b, and carotenoids, while enhanced oxidative damage in terms of increased levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and electrolyte leakage (EL) in both rice cultivars. Moreover, Cd stress hampered the activities of enzymatic antioxidants, i.e., superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), with lowest antioxidant activities were recorded at Cd100. The overall trend (lowest to highest) for antioxidant activities across treatments was recorded as Cd100 < Ca2+Cd100 < Cd50 < Ca1+Cd100 < CK < Ca1 < Ca1+Cd50 < Ca2+Cd50 < Ca2. Similarly, Ca amendment improved the proline, soluble protein, and soluble sugar contents in both rice cultivars under Cd stress condition. Comparing Ca2 with CK, the yield and related components, i.e., number of panicles, spikelets per panicle, seed setting rate, 1000 grain weight, and grain yield, were found to increase by 13.08, 2.39, 4.03, 5.86, and 27.53% for Guixiangzhan and 16.48, 5.19, 6.87, 15.44, and 51.16% for Meixiangzhan, respectively. Furthermore, Cd contents in roots, stems, leaves, and grains increased with increased Cd concentration applied and reduced with Ca amendment. The Cd contents in grains for all Ca+Cd levels are statistically at par with each other and significantly lower (P < 0.05) than those for individual Cd application. Hence, Ca amendment can be an appropriate approach to ameliorate the toxic effects of Cd in crops grown under Cd-contaminated soils.

Responses of plant growth, physiological, gas exchange parameters of super and non-super rice to rhizosphere temperature at the tillering stage

Temperature is one of the critical factors affecting rice growth and yield production. This study investigated the effects of rhizosphere temperature at the tillering stage on the growth, physiological parameters and gas exchange attributes of two rice cultivars, i.e., the super rice cultivar Yuxiangyouzhan and the non-super rice cultivar Xiangyaxiangzhan, under hydroponic conditions. Three rhizosphere temperature treatments, i.e., a low-rhizosphere-temperature treatment (LT, nutrient solution at 17.5 ± 1.5 °C), an ambient-temperature treatment (AT, nutrient solution at 27.5 ± 1.5 °C), and a high-rhizosphere-temperature treatment (HT, nutrient solution at 37.5 ± 1.5 °C), were applied in this study. The results showed significant differences in most of the rice growth and physiological and gas exchange parameters as a result of cultivar and rhizosphere temperature as well as their interaction. In addition, the marked reduction in total dry weight was positively correlated with a notable reduction in plant morphological parameters, such as the fresh and dry weight of the leaves and stem sheaths, and changes in gas exchange parameters. Moreover, antioxidant reactions were active in response to high and low rhizosphere temperatures, which varied in different plant tissues. These results suggested that the super and non-super rice were sensitive to high and low rhizosphere temperatures, respectively.

Rice seed priming with sodium selenate: Effects on germination, seedling growth, and biochemical attributes

The aim of this study was to determine the effects of sodium selenate (15, 30, 45, 60, 75, 90, and 105 mg kg⁻¹) on the germination and seedling growth of Changnongjing 1 rice (Oryza sativa L.) at 25 °C and 30 °C. Low selenate concentrations induced shorter and more uniform germination periods than did ultrapure water at both temperatures. Seedlings primed with low selenate concentrations were superior to those primed with ultrapure water in terms of plant height, fresh weight, dry matter accumulation, and soluble carbohydrate and protein contents. Lower selenate concentrations (15–75 mg kg⁻¹) induced higher chlorophyll and phenol contents in seedlings than did ultrapure water. Lower selenate concentrations also increased the superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione peroxidase (GPx) contents in seedlings and significantly decreased the stress-related malondialdehyde (MDA) content compared to ultrapure water. In conclusion, rice seedling germination and growth were promoted by priming with low selenate concentrations (15–75 mg kg⁻¹) but inhibited by priming with high selenate concentrations (90–105 mg kg⁻¹).

The genetics and biosynthesis of 2-acetyl-1-pyrroline in fragrant rice

Rice (Oryza sativa L.) is a staple food for the majority of the world's population. Rice fragrance, aroma, or scent is not just a cooking quality, but also an eating quality of rice. Rice fragrance is a trait that is widely desired among rice consumers. Consequently, rice producers are sorting for rice cultivars with strong fragrance. High demand for fragrant rice cultivars has prompted rice breeders and researchers to investigate the genetics and the ways to improve fragrance in rice. It has been established by many researches that fgr gene on the chromosome 8 of rice controls its fragrance. As with other plants, rice contains BADH but because rice does not accumulate GB, a catalyst for BADH coding, BADH1 on chromosome 4 of rice and BADH2 on chromosome 8 of rice have been widely reported to be responsible for encoding BADH. badh2, a recessive allele of BADH2 has been confirmed to be responsible for fragrance in rice. badh2 and its alleles have been associated with the accumulation and synthesis of 2AP. Proline, ornithine, glutamate, methylglyoxal, Δ1-pyrroline-5-carboxylate synthetase and glyceraldehyde-3-phosphate dehydrogenase have all been identified as the precursors for the synthesis and accumulation of 2AP. By reviewing and summarising the main results of various researchers, we have been able to elucidate how various genes and metabolites influence 2AP accumulation in fragrant rice. It is our hope that this paper will be beneficial to researchers, who are working on the improvement of rice fragrance.

Molecular basis for increased 2-acetyl-1-pyrroline contents under alternate wetting and drying (AWD) conditions in fragrant rice

Factors affecting rice aroma biosynthesis have been well documented previously, however the molecular mechanism lies behind the regulations in grain 2-acetyl-1-pyrroline (2AP) biosynthesis under alternate wetting and drying (AWD) remained largely unexplored. Present study investigated the effects of three irrigation regimes i.e., conventional irrigation (CI), alternate wetting and moderate drying (WMD), and alternate wetting and severe drying (WSD) on the yield, quality traits, intermediates, enzyme activities and genes involved in 2-acetyl-1-pyrroline biosynthesis in two fragrant rice cultivars viz, Meixiangzhan2 and Xiangyaxiangzhan. Results revealed that the levels of intermediates such as Δ1-pyrroline-5-carboxylate (P5C) and Δ1-pyrroline, and the activity of enzymes such as proline dehydrogenase (PRODH), Δ1-pyrroline-5-carboxylate synthetase (P5CS), diamine oxidase (DAO), and gene expressions of PRODH, P5CS2 and DAO were comparatively higher under AWD than CI in both aromatic rice cultivars. The levels of gamma-aminobutyric acid (GABA), betaine aldehyde dehydrogenase 2 (BADH2) and BADH2 gene were lower that together led to enhanced 2-AP contents in rice grains. Moreover, WMD irrigation improved yield and yield characters, while WSD irrigation reduced yield and quality traits of rice. Overall, up-regulation of P5C and Δ1-pyrroline and down-regulation of GABA under AWD treatments resulted in enhanced 2AP biosynthesis in both rice cultivars. Evaluation and adoption of AWD (within safe limits) at field level could be an alternative option to conventional flooded rice to get better yield and quality.

Ultrasonic seed treatment improved physiological and yield traits of rice under lead toxicity

Lead (Pb) is a highly toxic metal that damages normal plant metabolism and often results in reduced crop growth and yield. To measure whether or not ultrasonic seed (US) treatment alleviates Pb stress in rice, the seeds of two rice cultivars, i.e., Guangyan1 and Huahang31, were exposed to 30 min of ultrasonic vibration and then the seedlings were transplanted to Pb-contaminated soil. Results revealed that the Pb contents in roots, stems, leaves, panicles (at heading), and brown rice (at maturity) were lower in US treatment than control (CK; without US treatment); the trend for accumulation of Pb in different plant parts was recorded as: root ˃ stems ˃ leaves ˃ panicles ˃ brown rice in both rice cultivars. Overall, the Pb contents in the brown rice of Huahang31 were higher than those in Guangyan1. Moreover, the contents of proline and soluble protein as well as the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were significantly higher while the malondialdehyde (MDA) contents were significantly reduced in US treatment compared to CK. The effective panicle number, seed set percentage, grains per panicle, 1000-grain weight, and grain yield were increased by 8.9%, 5.3%, 6.8%, 4.4%, and 26.6% in Guangyan1 and 3.2%, 5.7%, 5.7%, 5.0%, and 24.2% in Huahang31, respectively in US treatment compared to CK. Hence, seed treatment with ultrasonic waves could improve rice performance and reduce brown rice Pb accumulation under Pb-polluted soils.

Genotype frequencies of human neutrophil antigen-3 in the Chinese Zhuang and Dong populations

Individuals with the human neutrophil antigen (HNA)-3b/3b type can produce HNA-3a antibodies, which have been reported to cause severe, sometimes fatal transfusion-related acute lung injury (TRALI). Our study aimed to determine the genotype frequency of HNA-3a/3b which will be helpful to estimate the potential risk for forming anti-HNA-3a, the clinically relevant antibody linked to TRALI in two different ethnic groups of southern China. Five hundred unrelated and healthy blood donors (284 male, 216 female; 300 Zhuangs, 200 Dongs) from the Guangxi Zhuang Autonomous Region were simultaneously typed for the HNA-3 allele using a polymerase chain reaction sequence-based typing (PCR-SBT) method. Genotype frequencies of HNA-3a/3a, HNA-3a/3b and HNA-3b/3b were 51.7%, 39.7% and 8.6% in the Zhuang population, and 44.0%, 49.0% and 7.0% in the Dong population, respectively. Homozygous HNA-3b/3b genotype frequency among the Zhuang population (8.6%) was significantly higher than previously reported in African Americans (0.4%), Brazilians (3.6%) and English Caucasians (2.9%) (p < .05). And the HNA-3b/3b genotype frequency among the Dong population was higher than African Americans (0.4%) (p < .05). This study showed Chinese Zhuang and Dong populations possessed a higher frequency of HNA-3b/3b genotype, suggesting that they may be at greater risk for developing anti-HNA-3a alloantibodies that may cause severe cases of TRALI. A molecular-based identification of the HNA-3b/3b genotype in all multiparous female blood donors was suggested to reduce the risk of TRALI following plasma and whole blood allogeneic transfusions.

Lead (Pb) Toxicity; Physio-Biochemical Mechanisms, Grain Yield, Quality, and Pb Distribution Proportions in Scented Rice

Lead (Pb) caused interruptions with normal plant metabolism, crop yield losses and quality issues are of great concern. This study assessed the physio-biochemical responses, yield and grain quality traits and Pb distribution proportions in three different fragrant rice cultivars i.e., Meixiangzhan-2, Xinagyaxiangzhan and Basmati-385. Plants were exposed to 400, 800, and 1,200 ppm of Pb while pots without Pb were taken as control (0 ppm). Our results showed that Pb toxicity significantly (P < 0.05) reduced photosynthetic pigments (chlorophyll contents and carotenoids) and inducted oxidative stress with increased production of hydrogen peroxide (H2O2), malanodialdehyde (MDA) and leaves leachates; while such effects were more apparent in Xinagyaxiangzhan than other two rice cultivars. Pb stress differentially affected the production protein, proline and soluble sugars; however the production rates were higher at heading stage (HS) than maturity stage (MS). Furthermore, Pb stress altered superoxide dismutase (SOD), peroxidases (POD), catalases (CAT) and ascorbate peroxidases (APX) activities and glutathione (GSH) and oxidized glutathione (GSSG) production in all rice cultivars at both HS and MS. All Pb levels reduced the yield and yield components of all rice cultivars; nonetheless such reductions were observed highest in Xinagyaxiangzhan (69.12%) than Meixiangzhan-2 (58.05%) and Basmati-385 (46.27%) and resulted in grain quality deterioration. Significant and positive correlations among rice yields with productive tillers/pot and grains per panicle while negative with sterility percentage were also observed. In addition, all rice cultivars readily taken up the Pb contents from soil to roots and transported upward in different proportions with maximum in roots followed by stemss, leaves, ears and grains. Higher proportions of Pb contents in above ground plant parts in Xinagyaxiangzhan possibly lead to maximum losses in this cultivar than other two cultivars; while less damage in Basmati-385 might be related to strong anti-oxidative defense system and lower proportions of Pb contents in its aerial parts.

The prevalence of and risk factors for prostatitis-like symptoms and its relation to erectile dysfunction in Chinese men

The aim of this study was to describe the prevalence of and risk factors for prostatitis-like symptoms and its relation to erectile dysfunction (ED) among southern Chinese men. Data were collected from 2790 men attending the Fangchenggang Area Male Healthy and Examination Survey from September 2009 to December 2009. The prostatitis-like symptoms were assessed by the NIH Chronic Prostatitis Symptom Index and ED was assessed using the 5-item International Index of Erectile Function. Lifestyle and demographic characteristics were obtained through a questionnaire. Prevalence of prostatitis-like symptoms was 12.4% among 2790 Chinese men aged 20-84 years. In smokers who smoked ≥20 cigarettes per day (age-adjusted OR = 1.29; 95% CI = 1.00-1.66; p = 0.04), physical inactivity (age-adjusted OR = 1.31; 95% CI = 1.03-1.66; p = 0.02) was a significant risk factor for prostatitis-like symptoms. Alcohol consumption (daily drinking) also was a risk factor for prostatitis-like symptoms, although the differences were not statistically significant (age-adjusted OR = 1.36; 95% CI = 0.96-1.92; p = 0.07). Those with diabetes may also be at higher risk for prostatitis-like symptoms (age-adjusted OR = 1.37; 95% CI = 0.85-2.21; p = 0.19). In addition, men with ED were more likely to have had prostatitis-like symptoms (age-adjusted OR = 1.86; 95% CI = 0.47-2.36; p < 0.0001), and the ORs increased with increasing severity of ED status (mild ED, mild to moderate ED, and moderate to severe ED were 1.57, 2.62, and 3.24, respectively. Test for trend, p = 0.0001). Our results show that prostatitis-like symptoms are prevalent in Southern China affecting men of all ages. Smoking, drinking, lack of physical activity, and elevated plasma glucose level were associated with an increased risk of prostatitis-like symptoms. In addition, our results reveal that ED accounted for a large proportion (61.5%) among men with prostatitis-like symptoms; we also confirm the magnitude of ED associated with prostatitis-like symptoms. Thus, interventions to evaluate and improve ED might help ameliorate prostatitis-like symptoms and vice versa.

Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes

Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice.

Interleukin-17 promotes prostate cancer via MMP7-induced epithelial-to-mesenchymal transition

Chronic inflammation has been associated with a variety of human cancers including prostate cancer. Interleukin-17 (IL-17) is a critical pro-inflammatory cytokine, which has been demonstrated to promote development of prostate cancer, colon cancer, skin cancer, breast cancer, lung cancer, and pancreas cancer. IL-17 promotes prostate adenocarcinoma with a concurrent increase of matrix metalloproteinase 7 (MMP7) expression in mouse prostate. Whether MMP7 mediates IL-17’s action and the underlying mechanisms remain unknown. We generated Mmp7 and Pten double knockout (Mmp7^−/− in abbreviation) mouse model and demonstrated that MMP7 promotes prostate adenocarcinoma through induction of epithelial-to-mesenchymal transition (EMT) in Pten-null mice. MMP7 disrupted E-cadherin/β-catenin complex to up-regulate EMT transcription factors in mouse prostate tumors. IL-17 receptor C and Pten double knockout mice recapitulated the weak EMT characteristics observed in Mmp7^−/− mice. IL-17 induced MMP7 and EMT in human prostate cancer LNCaP, C4-2B, and PC-3 cell lines, while siRNA knockdown of MMP7 inhibited IL-17-induced EMT. Compound III, a selective MMP7 inhibitor, decreased development of invasive prostate cancer in Pten single knockout mice. In human normal prostates and prostate tumors, IL-17 mRNA levels were positively correlated with MMP7 mRNA levels. These findings demonstrate that MMP7 mediates IL-17’s function in promoting prostate carcinogenesis through induction of EMT, indicating IL-17-MMP7-EMT axis as potential targets for developing new strategies in the prevention and treatment of prostate cancer.

Manganese-induced regulations in growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in fragrant rice

Micro-nutrient application is essential for normal plant growth while a little is known about manganese (Mn)-induced regulations in morpho-physiological attributes, aroma formation and enzyme involved in 2-acetyl-1-pyrroline (2-AP) biosynthesis in aromatic rice. Present study aimed to examine the influence of four levels of Mn i.e., Mn1 (100 mg MnSO4 pot(-1)), Mn2 (150 mg MnSO4 pot(-1)), Mn3 (200 mg MnSO4 pot(-1)), and Mn4 (250 mg MnSO4 pot(-1)) on the growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in two fragrant rice cultivars i.e., Meixiangzhan and Nongxiang 18. Pots without Mn application were served as control (Ck). Each pot contained 15 kg of soil. Effects on agronomic characters, quality attributes, 2-AP contents and enzymes involved in 2-AP biosynthesis have been studied in early and late season rice. Results depicted that Mn improved rice growth, yield and related characters, and some quality attributes significantly. It further up-regulated proline, pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP), soluble proteins and activities of proline dehydrogenase (ProDH), Δ(1) pyrroline-5-carboxylic acid synthetase (P5CS) ornithine aminotransferase (OAT) that led to enhanced 2-AP production in rice grains. Moreover, higher Mn levels resulted in increased grain Mn contents in both rice cultivars. Along with growth and yield improvement, Mn application significantly improved rice aromatic contents. Overall, Nongxiang 18 accumulated more 2-AP contents than Meixiangzhan in both seasons under Mn application. This study further explored the importance of Mn in rice aroma formation and signifies that micro-nutrients can play significant roles in rice aroma synthesis; however, intensive studies at molecular levels are still needed to understand the exact mechanisms of Mn to improve rice aroma formation.

Supplementation of 2-Ap, Zn and La Improves 2-Acetyl-1-Pyrroline Concentrations in Detached Aromatic Rice Panicles In Vitro

Aromatic rice is highly prized by consumers worldwide due to its special aromatic character. 2-acetyl-1-pyrroline (2-AP) is considered to be the single most important volatile compound responsible for aroma in aromatic rice. The present study demonstrated the effects of 2-AP, zinc (Zn) and lanthanum (La) on the 2-AP concentration of detached aromatic rice panicles in vitro. Detached panicles from three well-known aromatic cultivars, Guixiangzhan, Pin14, and Pin 15, were cultured separately in basic culture medium supplemented with 2-AP, Zn and La, and 2-AP concentrations were assessed at 7 and 14 days after culture (DAC). The results show that supplementation of 2-AP, Zn and La in the basic culture medium significantly increases the accumulation of proline. 2-AP concentration and the activity of proline dehydrogenase (ProDH) were also increased in rice grains. Zn concentrations were also found to be higher when Zn was added to the basic culture medium, and La concentrations in grains were too low to be measured. Additionally, grain 2-AP concentrations were significantly and positively correlated with proline concentrations, ProDH activities in grains and 2-AP in culture medium. In summary, higher grain 2-AP concentrations might be due to Zn- and La-induced increases in proline concentrations and ProDH activities, as well as the direct uptake and transportation of 2-AP from the culture medium. Furthermore, application of both Zn and La might be helpful for improving aroma formation in rice. However, interactions of both these elements with the complex process of 2-AP formation remain to be explored.