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.

The protective effects of polyamines on salinity stress tolerance in foxtail millet (Setaria italica L.), an important C4 model crop.

ABSTRACT: Soil salinity is a major abiotic stress that adversely affects crop growth, development and productivity worldwide. In this study, the individual and synergistic roles of putrescine (Put) and spermidine (Spd) in salinity stress tolerance of foxtail millet (Setaria italica L.) was assessed. In the present study, plants treated with combined biogenic amines Put + Spd possess very efficient antioxidant enzyme systems which help to control the uninhibited oxidation and protect the plants from oxidative damage by ROS scavenging. Additionally, lower concentration of Put + Spd under NaCl stress showed reduced hydrogen peroxide, electrolyte leakage and caspase-like activity than control. FTIR analysis underlying the ability of PAs induced tolerance and the chemical bonds of Put + Spd treated plants were reminiscent of control plants. Moreover, histochemical analysis with 2',7'-dichlorofluorescein diacetate (DCF-DA), 3,3'-Diaminobenzidine (DAB) and nitrotetrazolium blue chloride (NBT) revealed that ROS accumulation was inhibited by combined PAs under salt stress condition. These results showed that Put + Spd significantly improve the endogenous PAs, which enhance high-salinity stress tolerance by detoxifying ROS. For the first time, the synergistic ROS scavenging ability of Put along with Spd was investigated upon salinity tolerance in C4 model foxtail millet crop. Overall, our findings illustrated the implication for improving salinity tolerance of agronomically important crop species.

Role of activated charcoal and amino acids in developing an efficient regeneration system for foxtail millet (Setaria italica (L.) Beauv.) using leaf base segments.

An efficacious, reproducible direct in vitro regeneration system has been developed from leaf base segments (LBs) of six high yielding genotypes of foxtail millet (Setaria italica (L.) Beauv.). LBs excised from 4-day-old seedling were inoculated on Murashige and Skoog (MS) medium supplemented with different types and concentrations of cytokinins. The shoots induced per explant significantly increased with the supplementation of BAP to auxin containing medium. The results showed that a maximum shoot induction, 58.8% was obtained on MS medium incorporated with 8.9 µM BAP and 2.7 µM NAA in 'CO5' genotype. Further, the highest frequency of multiple shoots was produced on MS(I) medium containing 8.9 µM BAP, 2.7 µM NAA, 700 mg L-1 proline, 0.5 mg L-1 cysteine, 2.0 mg L-1 glycine and 150 mg L-1 arginine. MS(I) medium additionally fortified with 5.0 g L-1 activated charcoal (AC) was found to achieve the best precocious plant regeneration. Elongated shoots were rooted on half-strength MS medium amended with 2.9 µM IAA and achieved maximum root number (8.7) within 10 days. Rooted plantlets were acclimated in soil with 92% survival rate. Molecular marker analysis of in vitro regenerated and field grown plants revealed no somaclonal variations. Briefly, amino acids and activated charcoal could significantly enhance the foxtail millet direct multiple shoot proliferation and plant regeneration. Here we report, a short-term, genotype independent, direct plant regeneration protocol for future genetic transformation studies in foxtail millet genotypes.

Analysis of population structure and genetic diversity in an exotic germplasm collection of Eleusine coracana (L.) Gaertn. using genic-SSR markers.

Finger millet (Eleusine coracana (L.) Geartn.) is one of the important small millets serves as a food security crop because of its high nutritional values. The complex tetraploid genome of finger millet requires a large number of informative, functional DNA markers for different applications in genetics and breeding. Yet, less number of simple sequence repeat (SSR) markers have been developed from expressed sequence tags in finger millet. In the present study, 56 new genic SSR markers were developed from publicly available drought related ESTs. The 43 polymorphic markers were used to evaluate polymorphism, revealed a range of PIC value 0.41 to 0.79. Our results suggest that, analyzed genotypes have high genetic diversity with an average gene diversity (h) of 0.176 and Shannon's information index (I) of 0.315. We conclude that there was a higher gene exchange within populations, by the value of overall gene flow (Nm) of 0.7721. The unweighted pair group method with arithmetic mean and neighbor joining dendrogram generated three main clusters to differentiate genotypes and these results were also confirmed by PCA and PCoA analysis. The high genetic diversity (77%) was found within the populations in the analysis of molecular variance. A Bayesian model-based cluster analysis evidenced a high extent of admixture between the gene pools from the different geographical origins. Population based cluster analyses pointed out a strong pattern of 'isolation by distance'. Overall, these results underscored that this study showed a significantly high level of polymorphism, adequate genetic diversity and population structure which expand the modern genetic resources and its utility in various applications in genetics and genomics including association mapping and breeding.

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.