Chandana Pandey

Selenium and auxin mitigates arsenic stress in rice (Oryza sativa L.) by combining the role of stress indicators, modulators and genotoxicity assay.

Arsenic (As) is known to disrupt the biological function in plants by inhibiting their growth and developmental process, while selenium (Se) is an essential micronutrient within the appropriate amount. Phytohormone auxin on the other hand is an established growth regulator and plays a significant role in stress management. Present study is designed to see the effect of Se and auxin on morphological and biochemical characteristics and, on the genotoxicity in rice plants under As stress. The observations indicated that seedlings supplemented only with As showed inhibition in the growth parameters, however, co-application of Se and auxin improved growth of rice seedlings, level of stress indicators, (chlorophyll, protein, MDA content) and modulators (cysteine, proline) as compared the individual treatment of As. Genomic template stability calculated through changes in RAPD profile showed consistent results when compared with the indicator and modulator parameters. Altered DNA profile showed varying degrees of polymorphism, highest in roots of As treated seedlings and lowest in roots of Se+auxin and As+Se treated seedlings. Altogether, this study conclude that application of Se and auxin alone or in combination were more effective in lowering the As induced stress in rice.

Selenium amelioration of arsenic toxicity in rice shows genotypic variation: A transcriptomic and biochemical analysis

The toxic metalloid arsenic (As) is consumed mostly through contaminated rice. Therefore, reducing its accumulation and maintaining nutrient homeostasis in crop plants are imperative to ensure food safety. However, there is a dearth of information on the interrelationship between nutrient homeostasis and the regulatory mechanisms of arsenic-selenium (As-Se) interactive pathways responsible for stress tolerance. In the present study, experiments were conducted in hydroponically grown 12-day-old seedlings of rice (Oryza sativa L.) varieties (Pusa Basmati1 and IR64) treated with arsenite (AsIII) (150 μM), selenium (SeVI) (20 μM), and As + Se. It was observed that selenium supplementation ameliorated As toxicity by reducing its accumulation and retrieving As-induced nutrient deficiency. Significant decrease in As accumulation, H2O2 content, and fluorescent intensity of nitric oxide (NO), reactive oxygen species (ROS), and superoxide radical (O2.-) along with cell death with Se supplementation in both rice varieties demonstrated the protective role of Se as a probable ROS quencher. Addition of Se increased the enzyme activities of thiol metabolism and induced differential transcript accumulation patterns of sulfur-related genes. Nutrient level positively correlated with the differential expression pattern of NPK-related genes that play roles in metabolism and nutrient availability in both varieties. Though Pusa Basmati1 (PB1) showed higher tolerance to As, IR64 overcomes As toxicity more efficiently than PB1 in the presence of Se, which highlights that IR64 is a better performer in the presence of Se. Overall, this study provides novel insight into the role of Se in As-stressed rice genotypes through alteration of nutrient transporters and thiol-related genes.

Selenium enriched Garden gress ( Lepidium sativum L.): Role of antioxidants and stress markers

Selenium (Se) is considered as an essential micronutrient for humans and animals. Sprouts of Garden cress (Lepidium sativum) were treated with different concentration of Se, growth parameters, antioxidant enzymes and stress markers were studied. 10 μM Se would be more beneficial, as at this concentration it showed altered biochemical traits without showing any toxicity symptoms.

Silicon mediated genotoxic alterations in Brassica juncea under arsenic stress: comparative study of biochemical and molecular markers

ABSTRACT Arsenic (As), one of the most harmful toxicant at the global level, severely affects plant metabolism when taken up. Interestingly, the presence of silicon (Si) as a fertilizer in As-contaminated soil is an effective strategy to decrease As accumulation in plants. Brassica juncea (var. Varuna) were grown hydroponically to investigate the role of Si at biochemical and molecular levels under arsenite (As3+) stress. Seedlings of B. juncea were exposed to As3+, Si, and a combination of both elements. Our data demonstrated that seedlings exposed to As3+ showed an inhibition in shoot length, chlorophyll, carotenoid, and protein, while co-application of Si improved these growth parameters. Silicon supplementation reduced As accumulation in shoot. Increase/decrease was observed in stress-related parameters (cysteine and proline), antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, and catalase), and oxidative stress markers (malondialdehyde and H2O2), which were improved upon co-application of Si as compared to As3+ alone treatment. Random amplified polymorphic DNA (RAPD) is a suitable biomarker assay for plants for assessing the genotoxicity. Seven RAPD primers produced a total of 39 and 48 bands in the leaves of the untreated and treated seedlings, respectively. The RAPD band-profiles and genomic template stability were consistent with other growth and physiological parameters. In conclusion, the genotoxic alterations along with the biochemical parameters indicate that the exposure to Si mitigates As3+-induced oxidative stress by improving the stress-related parameters and antioxidant system in B. juncea.