Overexpression of Erianthus arundinaceus DREB2 Transcription Factor Ameliorates the Salinity and Drought Tolerance in Eleusine coracana Cultivars

Drought and salinity are the major constraints on agricultural production worldwide and a remarkable attempt is being made to improve the plant yields in the direction of increasing water deficit. We have developed transgenic finger millet cultivars ‘CO(Ra)-14’ and ‘Paiyur-2’ overexpressing Erianthus arundinaceous DREB2 (EaDREB2) transcription factor confirmed by PCR and Southern stably expressed in T0 and T1. These transgenic lines were tolerant to high salinity and severe drought stress conditions without affecting the morphological or agronomic characters. Analysis of morpho-physiological characters revealed that overexpression of EaDREB2 gene was associated with maintenance of chlorophyll content, increased relative water content, improved accumulation of the osmotic substance such as proline and decreased electrolyte leakage, under both saline and drought stresses. After treating the plants to progressive drought and salinity stress, transgenic lines showed less chlorophyll reduction and moderate growth inhibition than the controls. The majority of the transformed lines showed prominent tolerance to salinity and drought with significant spikelet fertility and higher grain yield compared to the controls at stressed and unstressed conditions. This is the first holistic report on development of drought and saline tolerance in finger millet through transgenic modification and it is essential to benefit the farmers from seasonal stress

Effect of salinity stress on finger millet (Eleusine coracana (L.) Gaertn): Histochemical and morphological analysis of coleoptile and coleorhizae

The current study deals with the impact of salinity stress on growth and development of finger millet genotype ‘CO(Ra)-14’. The seeds were germinated on Murashige and Skoog solid medium supplemented with various concentrations of sodium chloride (NaCl) (0, 50, 100, 150 or 200 mM) for 15 days. Several physiological indices, including relative growth rate, electrolyte leakage, proline and chlorophyll (a, b and a + b) content, cell viability, hydrogen peroxide and caspase-like activity were measured to analyze the physiological and biochemical characteristics of saline stress. In addition, we also analyzed saline stress induced histochemical changes and level of lignin in the coleoptile and coleorhizae tissues. Relative growth of leaves and shoots of finger millet genotype ‘CO(Ra)-14’ exposed to 150 mM NaCl concentration was decreased while root length was increased. In addition, there was a significant increase in the levels of electrolyte leakage, contents of proline and hydrogen peroxide, and caspase-like activity from 0 to 200 mM NaCl. Chlorophyll and relative water contents were significantly reduced with decreased leaf succulence under increasing salinity. The microscopic observations of coleoptile and coleorhizae cross sections revealed considerable variations viz., length of epidermal cells, surface area and width of the cells with increasing salinity. Saline treated tissues were severely damaged and were intensely stained with phloroglucinol (suggesting the accumulation of cell bound phenolic compounds). Overall finger millet genotype ‘CO(Ra)-14’ showed a diverse response to salinity stress starting from seed germination to growth, and above 100 mM NaCl salinity is toxic to finger millet genotype ‘CO(Ra)-14’

Analysis of genetic variation in sorghum (Sorghum bicolor (L.) Moench) genotypes with various agronomical traits using SPAR methods

Genetic variation among 45 genotypes of sorghum (Sorghum bicolor L.) representing seven subpopulations was assessed using three single primer amplification reaction (SPAR) methods viz., inter-simple sequence repeat (ISSR), random amplified polymorphic DNA (RAPD) and directed amplification of minisatellite-region DNA (DAMD). Totally 15 ISSR, 8 RAPD and 7 DAMD primers generated 263 amplification products, accounting for 84.6% polymorphism across all the genotypes. The Mantel's test of correlation revealed the best correlation between ISSR and cumulative data with a correlation coefficient (r) of 0.84. Assessment of population diversity indicated that the maximum intra population genetic diversity was recorded among high FeZn lines (HFL) having maximum values of Nei's genetic diversity (h) (0.244), Shannon information index (I) (0.368) and the percentage of polymorphic loci (Pp) (72.65%) while the corresponding lowest values of 0.074, 0.109 and 17.95% respectively were observed among the members of MDT subpopulation. The mean coefficient of gene differentiation (GST) and the gene flow (Nm) between populations were observed to be 0.396 and 0.7680 respectively. The analysis of molecular variance (AMOVA) suggested that maximum genetic variation exists within populations (95%) than among populations (5%). Thus the information obtained from this study could be utilized in sorghum breeding programmes for the development of varieties with improved nutrition and agronomic values in future

Conventional and Omics Approaches for Understanding the Abiotic Stress Response in Cereal Crops—An Updated Overview

Cereals have evolved various tolerance mechanisms to cope with abiotic stress. Understanding the abiotic stress response mechanism of cereal crops at the molecular level offers a path to high-yielding and stress-tolerant cultivars to sustain food and nutritional security. In this regard, enormous progress has been made in the omics field in the areas of genomics, transcriptomics, and proteomics. Omics approaches generate a massive amount of data, and adequate advancements in computational tools have been achieved for effective analysis. The combination of integrated omics and bioinformatics approaches has been recognized as vital to generating insights into genome-wide stress-regulation mechanisms. In this review, we have described the self-driven drought, heat, and salt stress-responsive mechanisms that are highlighted by the integration of stress-manipulating components, including transcription factors, co-expressed genes, proteins, etc. This review also provides a comprehensive catalog of available online omics resources for cereal crops and their effective utilization. Thus, the details provided in the review will enable us to choose the appropriate tools and techniques to reduce the negative impacts and limit the failures in the intensive crop improvement study

Phytosterols in Seaweeds: An Overview on Biosynthesis to Biomedical Applications

Seaweed extracts are considered effective therapeutic alternatives to synthetic anticancer, antioxidant, and antimicrobial agents, owing to their availability, low cost, greater efficacy, eco-friendliness, and non-toxic nature. Since the bioactive constituents of seaweed, in particular, phytosterols, possess plenty of medicinal benefits over other conventional pharmaceutical agents, they have been extensively evaluated for many years. Fortunately, recent advances in phytosterol-based research have begun to unravel the evidence concerning these important processes and to endow the field with the understanding and identification of the potential contributions of seaweed-steroidal molecules that can be used as chemotherapeutic drugs. Despite the myriad of research interests in phytosterols, there is an immense need to fill the void with an up-to-date literature survey elucidating their biosynthesis, pharmacological effects, and other biomedical applications. Hence, in the present review, we summarize studies dealing with several types of seaweed to provide a comprehensive overview of the structural determination of several phytosterol molecules, their properties, biosynthetic pathways, and mechanisms of action, along with their health benefits, which could significantly contribute to the development of novel drugs and functional foods