Engineering legumes for drought stress tolerance: Constraints, accomplishments, and future prospects

Correlates of Food Contamination by Heavy Metals in Northwest Nigeria

Background

The increasing cases of chronic kidney disease is a global public health concern. The potential link between consumption of food contaminated with heavy metals and development of end stage renal disease is becoming an emerging challenge. This study aimed to identify heavy metal contaminants in food and environmental risk factors for development of chronic kidney disease in Nigeria.

Methods

Cross-sectional survey in 4 high burden local government areas of Jigawa state, northwest Nigeria.

Results

The median age of the respondents was 45 years (interquartile range = 30-80) years. All the households had normal values of cadmium in the food analyzed. The majority of households (97.8%) had elevated mercury levels in analyzed food. Approximately 4.2% of households had increased lead levels. Elevated mercury levels were significantly higher in households that did not cultivate the food they consumed (median = 2.503 mg/kg, P = .05), those that did not use fertilizer on their farms (median = 2.522 mg/kg, P = .02), and those whose farms were located outside their communities (median = 2.733 mg/kg, P = .020). Households that did not use fertilizer on the farm (median = 0.027 mg/kg, P = .007), and those that primarily consumed rice (median = 0.023 mg/kg, P = .005) had significantly higher lead concentrations.

Conclusions

We identified high levels of mercury in food samples of the majority of the households studied. Elevated levels of mercury were associated with food cultivation practices and fertilizer use. We recommend future studies that will identify points of food contamination and inform the development of appropriate environmental remediation measures.

Transcriptome profiling reveals the impact of various levels of biochar application on the growth of flue-cured tobacco plants

BACKGROUND

Biochar, a carbon-rich source and natural growth stimulant, is usually produced by the pyrolysis of agricultural biomass. It is widely used to enhance plant growth, enzyme activity, and crop productivity. However, there are no conclusive studies on how different levels of biochar application influence these systems.

METHODS AND RESULTS

The present study elucidated the dose-dependent effects of biochar application on the physiological performance, enzyme activity, and dry matter accumulation of tobacco plants via field experiments. In addition, transcriptome analysis was performed on 60-day-old (early growth stage) and 100-day-old (late growth stage) tobacco leaves to determine the changes in transcript levels at the molecular level under various biochar application levels (0, 600, and 1800 kg/ha). The results demonstrated that optimum biochar application enhances plant growth, regulates enzymatic activity, and promotes biomass accumulation in tobacco plants, while higher biochar doses had adverse effects. Furthermore, transcriptome analysis revealed a total of 6561 differentially expressed genes (DEGs) that were up- or down-regulated in the groupwise comparison under different treatments. KEGG pathways analysis demonstrated that carbon fixation in photosynthetic organisms (ko00710), photosynthesis (ko00195), and starch and sucrose metabolism (ko00500) pathways were significantly up-regulated under the optimal biochar dosage (600 kg/ha) and down-regulated under the higher biochar dosage (1800 kg/ha).

CONCLUSION

Collectively, these results indicate that biochar application at an optimal rate (600 kg/ha) could positively affect photosynthesis and carbon fixation, which in turn increased the synthesis and accumulation of sucrose and starch, thus promoting the growth and dry matter accumulation of tobacco plants. However, a higher biochar dosage (1800 kg/ha) disturbs the crucial source-sink balance of organic compounds and inhibits the growth of tobacco plants.