Comparative genomics of light harvesting chlorophyll (LHC) gene family and impact of chlorophyll-A contents under drought stress in Helianthus annuus.

Drought is one of the main environmental stressors that can alter the water status of plants; negatively affect growth, assimilation, and photosynthesis; and eventually reduce crop yield. We explored the dependence of drought tolerance traits on chlorophyll-A content. Local sunflower cultivars (FH-01, FH-628, FH-633, FH-572, and FH-653) were grown in pots and subjected to drought by withholding water for 10, 15, or 20 d. One month after germination, the leaves of the treated and non-treated plants were collected and subjected to biochemical analyses. Under different water stress levels, the levels of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and proline increased, whereas those of chlorophyll-A decreased. Regression analysis clearly found that proline (-0.442), POD (-0.528), SOD (-0.532), and CAT (-0.814) have negative beta coefficient values. Phylogenetic analysis revealed that the LHC gene family is divided into six clades. Subcellular locations indicated that most LHC genes were located in the chloroplast; however, only few genes were present in the peroxisomes and endoplasmic reticulum. Our research found that Arabidopsis thaliana LHC genes were highly homologous to the LHC genes of Helianthus annuus. Furthermore, the LHC genes of both species are located in the chloroplasts; therefore, they play a role in photosynthesis and renewable energy production. This study opens a new horizon for discussing the role of chlorophyll-A in the drought-related traits of sunflowers.

Tackling microplastics pollution in global environment through integration of applied technology, policy instruments, and legislation.

Microplastic pollution is a serious environmental problem that affects both aquatic and terrestrial ecosystems. Small particles with size of less than 5 mm, known as microplastics (MPs), persist in the environment and pose serious threats to various species from micro-organisms to humans. However, terrestrial environment has received less attention than the aquatic environment, despite being a major source of MPs that eventually reaches water body. To reflect its novelty, this work aims at providing a comprehensive overview of the current state of MPs pollution in the global environment and various solutions to address MP pollution by integrating applied technology, policy instruments, and legislation. This review critically evaluates and compares the existing technologies for MPs detection, removal, and degradation, and a variety of policy instruments and legislation that can support the prevention and management of MPs pollution scientifically. Furthermore, this review identifies the gaps and challenges in addressing the complex and diverse nature of MPs and calls for joint actions and collaboration from stakeholders to contain MPs. As water pollution by MPs is complex, managing it effectively requires their responses through the utilization of technology, policy instruments, and legislation. It is evident from a literature survey of 228 published articles (1961-2023) that existing water technologies are promising to remove MPs pollution. Membrane bioreactors and ultrafiltration achieved 90% of MPs removal, while magnetic separation was effective at extracting 88% of target MPs from wastewater. In biological process, one kg of wax worms could consume about 80 g of plastic/day. This means that 100 kg of wax worms can eat about 8 kg of plastic daily, or about 2.9 tons of plastic annually. Overall, the integration of technology, policy instrument, and legislation is crucial to deal with the MPs issues.

Source, occurrence, distribution, fate, and implications of microplastic pollutants in freshwater on environment: A critical review and way forward.

The generation of microplastics (MPs) has increased recently and become an emerging issue globally. Due to their long-term durability and capability of traveling between different habitats in air, water, and soil, MPs presence in freshwater ecosystem threatens the environment with respect to its quality, biotic life, and sustainability. Although many previous works have been undertaken on the MPs pollution in the marine system recently, none of the study has covered the scope of MPs pollution in the freshwater. To consolidate scattered knowledge in the literature body into one place, this work identifies the sources, fate, occurrence, transport pathways, and distribution of MPs pollution in the aquatic system with respect to their impacts on biotic life, degradation, and detection techniques. This article also discusses the environmental implications of MPs pollution in the freshwater ecosystems. Certain techniques for identifying MPs and their limitations in applications are presented. Through a literature survey of over 276 published articles (2000-2023), this study presents an overview of solutions to the MP pollution, while identifying research gaps in the body of knowledge for further work. It is conclusive from this review that the MPs exist in the freshwater due to an improper littering of plastic waste and its degradation into smaller particles. Approximately 15-51 trillion MP particles have accumulated in the oceans with their weight ranging between 93,000 and 236,000 metric ton (Mt), while about 19-23 Mt of plastic waste was released into rivers in 2016, which was projected to increase up to 53 Mt by 2030. A subsequent degradation of MPs in the aquatic environment results in the generation of NPs with size ranging from 1 to 1000 nm. It is expected that this work facilitates stakeholders to understand the multi-aspects of MPs pollution in the freshwater and recommends policy actions to implement sustainable solutions to this environmental problem.

Genome-wide comparison and identification of myosin gene family in Arabidopsis thaliana and Helianthus annuus.

Myosins are essential components of organelle trafficking in all the eukaryotic cells. Myosin driven movement plays a vital role in the development of pollen tubes, root hairs and root tips of flowering plants. The present research characterized the myosin genes in Arabidopsis thaliana and Helianthus annuus by using different computational tools. We discovered a total of 50 myosin genes and their splice variants in both pant species. Phylogenetic analysis indicated that myosin genes were divided into four subclasses. Chromosomal location revealed that myosin genes were located on all five chromosomes in A. thaliana, whereas they were present on nine chromosomes in H. annuus. Conserved motifs showed that conserved regions were closely similar within subgroups. Gene structure analysis showed that Atmyosin2.2 and Atmyosin2.3 had the highest number of introns/exons. Gene ontology analysis indicated that myosin genes were involved in vesicle transport along actin filament and cytoskeleton trafficking. Expression analysis showed that expression of myosin genes was higher during the flowering stage as compared to the seedling and budding stages. Tissue specific expression indicated that HanMYOSIN11.2, HanMYOSIN16.2 were highly expressed in stamen, whereas HanMYOSIN 2.2, HanMYOSIN 12.1 and HanMYOSIN 17.1 showed higher expression in nectary. This study enhance our understanding the function of myosins in plant development, and forms the basis for future research about the comparative genomics of plant myosin in other crop plants.

Citric acid assisted phytoextraction of nickle from soil helps to tolerate oxidative stress and expression profile of NRAMP genes in sunflower at different growth stages.

Introduction: Soil polluted with Nickel (Ni) adversely affects sunflower growth resulting in reduced yield. Counterbalancing Ni toxicity requires complex molecular, biochemical, and physiological mechanisms at the cellular, tissue, and whole plant levels, which might improve crop productivity. One of the primary adaptations to tolerate Ni toxicity is the enhanced production of antioxidant enzymes and the elevated expression of Ni responsive genes. Methods: In this study, biochemical parameters, production of ROS, antioxidants regulation, and expression of NRAMP metal transporter genes were studied under Ni stress in sunflower. There were four soil Ni treatments (0, 50, 100, and 200 mg kg-1 soil), while citric acid (CA, 5 mM kg-1 soil) was applied on the 28th and 58th days of plant growth. The samples for all analyses were obtained on the 30th and 60th day of plant growth, respectively. Results and discussion: The results indicated that the concentrations of Ni in roots and shoots were increased with increasing concentrations of Ni at both time intervals. Proline contents, ascorbic acid, protein, and total phenolics were reduced under Ni-stress, but with the application of CA, improvement was witnessed in their contents. The levels of malondialdehyde and hydrogen peroxide were enhanced with the increasing concentration of Ni, and after applying CA, they were reduced. The contents of antioxidants, i.e., catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase, were increased at 50 ppm Ni concentration and decreased at higher concentrations of Ni. The application of CA significantly improved antioxidants at all concentrations of Ni. The enhanced expression of NRAMP1 (4, 51 and 81 folds) and NRAMP3 (1.05, 4 and 6 folds) was found at 50, 100 and 200ppm Ni-stress, respectively in 30 days old plants and the same pattern of expression was recorded in 60 days old plants. CA further enhanced the expression at both developmental stages. Conclusion: In conclusion, CA enhances Ni phytoextraction efficiency as well as protect plant against oxidative stress caused by Ni in sunflower.

Molecular Aspects of MicroRNAs and Phytohormonal Signaling in Response to Drought Stress: A Review.

Phytohormones play an essential role in plant growth and development in response to environmental stresses. However, plant hormones require a complex signaling network combined with other signaling pathways to perform their proper functions. Thus, multiple phytohormonal signaling pathways are a prerequisite for understanding plant defense mechanism against stressful conditions. MicroRNAs (miRNAs) are master regulators of eukaryotic gene expression and are also influenced by a wide range of plant development events by suppressing their target genes. In recent decades, the mechanisms of phytohormone biosynthesis, signaling, pathways of miRNA biosynthesis and regulation were profoundly characterized. Recent findings have shown that miRNAs and plant hormones are integrated with the regulation of environmental stress. miRNAs target several components of phytohormone pathways, and plant hormones also regulate the expression of miRNAs or their target genes inversely. In this article, recent developments related to molecular linkages between miRNAs and phytohormones were reviewed, focusing on drought stress.

Plant Growth-Promoting Rhizobacteria Eliminate the Effect of Drought Stress in Plants: A Review.

Plants evolve diverse mechanisms to eliminate the drastic effect of biotic and abiotic stresses. Drought is the most hazardous abiotic stress causing huge losses to crop yield worldwide. Osmotic stress decreases relative water and chlorophyll content and increases the accumulation of osmolytes, epicuticular wax content, antioxidant enzymatic activities, reactive oxygen species, secondary metabolites, membrane lipid peroxidation, and abscisic acid. Plant growth-promoting rhizobacteria (PGPR) eliminate the effect of drought stress by altering root morphology, regulating the stress-responsive genes, producing phytohormones, osmolytes, siderophores, volatile organic compounds, and exopolysaccharides, and improving the 1-aminocyclopropane-1-carboxylate deaminase activities. The use of PGPR is an alternative approach to traditional breeding and biotechnology for enhancing crop productivity. Hence, that can promote drought tolerance in important agricultural crops and could be used to minimize crop losses under limited water conditions. This review deals with recent progress on the use of PGPR to eliminate the harmful effects of drought stress in traditional agriculture crops.

Comparative genomic analysis of MYB transcription factors for cuticular wax biosynthesis and drought stress tolerance in Helianthus annuus L.

Sunflower is an important oil-seed crop in Pakistan, it is mainly cultivated in the spring season. It is severely affected by drought stress resulting in lower yield. Cuticular wax acts as the first defense line to protect plants from drought stress condition. It seals the aerial parts of plants and reduce the water loss from leaf surfaces. Various myeloblastosis (MYB) transcription factors (TFs) are involved in biosynthesis of epicuticular waxes under drought-stress. However, less information is available for MYB, TFs in drought stress and wax biosynthesis in sunflower. We used different computational tools to compare the Arabidopsis MYB, TFs involved in cuticular wax biosynthesis and drought stress tolerance with sunflower genome. We identified three putative MYB genes (MYB16, MYB94 and MYB96) in sunflower along with their seven homologs in Arabidopsis. Phylogenetic association of MYB TFs in Arabidopsis and sunflower indicated strong conservation of TFs in plant species. From gene structure analysis, it was observed that intron and exon organization was family-specific. MYB TFs were unevenly distributed on sunflower chromosomes. Evolutionary analysis indicated the segmental duplication of the MYB gene family in sunflower. Quantitative Real-Time PCR revealed the up-regulation of three MYB genes under drought stress. The gene expression of MYB16, MYB94 and MYB96 were found many folds higher in experimental plants than control. The present study provided the first insight into MYB TFs family's characterization in sunflower under drought stress conditions and wax biosynthesis TFs.

Application of ANN to predict performance and emissions of SI engine using gasoline-methanol blends.

The deployment of methanol like alternative fuels in engines is a necessity of the present time to comprehend power requirements and environmental pollution. Furthermore, a comprehensive prediction of the impact of the methanol-gasoline blend on engine characteristics is also required in the era of artificial intelligence. The current study analyzes and compares the experimental and Artificial Neural Network (ANN) aided performance and emissions of four-stroke, single-cylinder SI engine using methanol-gasoline blends of 0%, 3%, 6%, 9%, 12%, 15%, and 18%. The experiments were performed at engine speeds of 1300-3700 rpm with constant loads of 20 and 40 psi for seven different fractions of fuels. Further, an ANN model has developed setting fuel blends, speed and load as inputs, and exhaust emissions and performance parameters as the target. The dataset was randomly divided into three groups of training (70%), validation (15%), and testing (15%) using MATLAB. The feedforward algorithm was used with tangent sigmoid transfer active function (tansig) and gradient descent with an adaptive learning method. It was observed that the continuous addition of methanol up to 12% (M12) increased the performance of the engine. However, a reduction in emissions was observed except for NOx emissions. The regression correlation coefficient (R) and the mean relative error (MRE) were in the range of 0.99100-0.99832 and 1.2%-2.4% respectively, while the values of root mean square error were extremely small. The findings depicted that M12 performed better than other fractions. ANN approach was found suitable for accurately predicting the performance and exhaust emissions of small-scaled SI engines.