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Plants are regularly exposed to biotic and abiotic stresses that adversely affect agricultural production. Omics has gained momentum in the last two decades, fueled by statistical methodologies, computational capabilities, mass spectrometry, nucleic-acid sequencing, and peptide-sequencing platforms. Functional genomics—especially metabolomics, transcriptomics, and proteomics—have contributed substantially to plant molecular responses to stress. Recent progress in reverse and forward genetics approaches have mediated high-throughput techniques for identifying stress-related genes. Furthermore, web-based genetic databases have mediated bioinformatics techniques for detecting families of stress-tolerant genes. Gene ontology (GO) databases provide information on the gene product’s functional features and help with the computational estimation of gene function. Functional omics data from multiple platforms are useful for positional cloning. Stress-tolerant plants have been engineered using stress response genes, regulatory networks, and pathways. The genome-editing tool, CRISPR-Cas9, reveals the functional features of several parts of the plant genome. Current developments in CRISPR, such as de novo meristem induction genome-engineering in dicots and temperature-tolerant LbCas12a/CRISPR, enable greater DNA insertion precision. This review discusses functional omics for molecular insight and CRISPR-Cas9-based validation of gene function in crop plants. Omics and CRISPR-Cas9 are expected to garner knowledge on molecular systems and gene function and stress-tolerant crop production.

Sustainable sunflower yield is under threat by a significant rise in global temperatures. Therefore, the development of a heat-resistant sunflower breeding population or hybrid is important for sustainable yield under high temperatures. Although there are a significant number of studies aimed at understanding the mechanism of heat resistance, only few direct approaches were made to improve heat resistance in sunflower. When breeding for heat resistance, the selection criteria are important. A desirable screening criterion should be rapid, highly heritable, and allow for the discrimination of resistant and susceptible ecotypes before reproductive maturity so that undesirable plants can be eliminated. In contrast, destructive selection criteria are not applicable for a segregating population. On the basis of an extensive review of data and experimentation, traits such as leaf and head orientation at the time of anthesis are proposed for practical utilization of sunflower heat-resistant breeding. These traits could be utilized as markers linked with heat avoidance. The traits are simply inherited, non-destructive, non-laborious, and show no impact of the environment and are independent of genotype × environment.

Climate change exacerbates flooding problems due to hurricanes followed by heavy rains, particularly in sub-tropical regions. Consequently, submerged plants experience hypoxia stress which limits agronomic and horticultural crop growth and production. Hypoxia causes oxidative damage by accelerating the lipid peroxidation associated with O₂- and H₂O₂ levels. Additionally, hypoxia increases the accumulation of organic osmoprotectants and antioxidant activity, whereas it decreases the macronutrient (N, P, K, and Zn) uptake. This study aimed at investigating the effects of flooding-induced hypoxia stress on the growth and the physiological, biochemical, and nutritional characteristics of the hydroponically grown southern highbush blueberry (cv. Jewel) plants. In addition, the hypoxia-mitigating effects of conventional silicon (Si-C) and silicon nanoparticles (SiNPs) and their application methods (foliar vs. foliar and rootzone application) were also appraised. Both the Si-C and the SiNPs efficiently alleviated hypoxia-induced oxidative and osmotic damage to cells by enhancing the activities of the enzymatic antioxidants (ascorbate peroxidase, catalase, dehydroascorbate reductase, superoxide dismutase, peroxidase, guaiacol peroxidase, monodehydroascorbate, reductase); the non-enzymatic antioxidants (ascorbic acid and glutathione contents); and the accumulation of compatible solutes (proline and glycinebetaine) in leaves and roots. However, the SiNPs were more effective than Si-C at improving antioxidant activities and osmolytes formation. A strong negative correlation between the antioxidant activities and the lipid peroxidation rate was observed in the SiNP-treated plants under hypoxia stress. The SiNPs also regulated nutrient uptake by increasing the K, N, P, and Zn concentrations while decreasing Fe and Mn concentrations to a less toxic level. Blueberry plants treated with SiNPs responded more effectively to hypoxia stress by maintaining higher antioxidant and osmoprotectant concentrations than blueberry plants treated with Si-C. Additionally, the foliar and rootzone applications yielded better results than the foliar applications only.

Drought is a major constraint for sunflower (Helianthus annuus) production worldwide. Drought tolerance traits have been identified in the related wild species Helianthus argophyllus. This study was initiated to develop sunflower drought-tolerant genotypes by crossing cultivated sunflower with this species and analyze drought tolerance traits in the H. annuus and H. argophyllus populations, H. annuus intraspecific hybrids, and H. annuus × H. argophyllus interspecific hybrids along with the commercial hybrid Hysun-33 under three stress regimes: exogenous application of ABA, both by foliar spray and irrigation, and 5% PEG-induced osmotic stress. H. argophyllus populations had a significantly lower leaf area and higher water-use efficiency and leaf cuticular wax content under all treatments, and maintained a higher net photosynthetic rate and stomatal conductance under osmotic stress. Small leaf area and high cuticular waxes content of the wild species were, however, not inherited in interspecific hybrids which suggested for selection in F₂ for these traits. Therefore, transgressive plants were selected in the F₂ population to establish F₃ plant progenies with silver-leafed canopy of H. argophyllus which showed higher achene yield under stress condition. These results are discussed with a view to using H. argophyllus to improve drought tolerance in cultivated sunflower.