Abiotic Stress Tolerance in Crop Plants: Role of Phytohormones

Crop plants are encountered by various abiotic pressures which limit their growth and development. Stresses such as drought, heat, pathogen attack, heavy metal, salinity, and radiations impose negative effect on crop plants. The reduction in crop productivity in the current era of climate change is compromising the efforts/strategies used for sustainable agricultural practices. Therefore, plant stress physiologists are engineering plants with suitable exogenous signaling elicitors to engineer tolerance to various stresses. In the present chapter, an appraisal has been made in the “Introduction” section to first assess the damages caused by various abiotic stresses in crop plants. In the second section, we attempt to summarize the role of various plant hormones, namely, salicylic acid (SA), brassinosteroids (BRs), ethylene (ET), and methyl jasmonate (MJ) in enhancing abiotic stress tolerance. The current concept may lead to the development of strategies for unraveling the underlying mechanisms of plant hormone-mediated abiotic stress tolerance in crop plants

Isolation and Molecular Characterization of Pseudomonas aeruginosa Lytic Bacteriophages as a Potential Therapeutic Alternative to Traditional Antibiotics

The emergence of antibiotic-resistant bacteria has led to increased bacterial infections that are difficult to treat. Bacteriophage therapy presents a potential solution to this problem. In this study, three phages isolated from different water sources in Ismailia were identified as potential candidates for bacteriophage therapy to control Pseudomonas aeruginosa bacteria. The phages were characterized according to morphology, host range, physical characteristics, and genetic differences. Based on their head and tail features, TEM images were utilized to identify two phages from the Siphoviridae family and one from the Myoviridae family. The phages were also tested for their tolerance to different physical and chemical factors such as temperature, pH, salinity, chloroform, and exposure to the laser, blood plasma, and essential oils. The three phages exhibited different preferences and tolerances to these factors, suggesting that they may be effective against different bacterial strains of P. aeruginosa in different environments. The study demonstrates the potential of phage therapy as an alternative to antibiotic therapy and highlights the importance of understanding phage characteristics in developing effective phage formulations. &nbsp

Influence of different levels of Zn on the mycorrhizal colonization of wheat.

<p>F% Frequency of mycorrhizal root segments, M% intensity of mycorrhizal colonization in the root, A% arbuscular frequency in the roots. The data represented are an average of three replicates (mean ± SD) followed by one standard deviation.</p

The phytoextraction efficiency (%), metal uptake (g pot^-1), and bioaccumulation factor (BCF) of Zn of wheat subjected to zinc treatments.

<p>Data presented as the mean of three replicates followed by the standard deviation (Mean±SD).</p

Acetylsalicylic acid enhance tolerance of Phaseolus vulgaris L. to chilling stress, improving photosynthesis, antioxidants and expression of cold stress responsive genes

Abstract Background High and low temperatures constitute the most damaging type of abiotic stress and limit the survival, and productivity of plants. The present study aimed to evaluate the role of exogenous applications of acetylsalicylic acid (ASA) in reducing the deleterious effects of cold stress. Phaseolus vulgaris L. seedlings were treated with foliar-sprayed ASA at concentrations of 0–3 mM and then subjected to chilling stress at 4 °C for 2 or 4 days. Results Growth, photosynthesis, biochemical alterations, oxidative damage and antioxidant enzyme activities as well as the expression of cold-responsive genes (CBF3–COR47), were monitored during the experiment. ASA applications substantially improved several growth and photosynthetic parameters, including shoot biomass, dry weight, and photosynthetic pigments, of P. vulgaris seedlings exposed to different durations of chilling stresses. The ASA foliar spray treatments significantly (p < 0.05) rescued the growth and photosynthetic pigments of P. vulgaris seedlings under different chilling stresses. The total soluble sugars markedly increased during 0–4 days of chilling stress following ASA foliar spraying. The exogenous application of ASA significantly (p < 0.05) increased the accumulation of proline in P. vulgaris seedlings under chilling stress. At the gene expression level, ASA significantly (p < 0.05) upregulated the cold-responsive genes CBF3 and COR47. Conclusions As a result, we speculate that, the application of exogenous ASA alleviated the adverse effects of chilling stress on all measured parameters, and 1 and 2 mM ASA exhibited the greatest effects

Influence of mycorrhizal colonization on lipid peroxidation as MDA (mmole g^-1 FW).

<p><b>The data represented are an average of five replicates; the error bars represent a standard error for the means.</b> ANOVA was performed to assess differences between treatment groups, followed by Duncan's multiple-rank comparisons. Media with similar letters are not significantly different according to Duncan's multiple range comparisons.</p

Mineral content in shoots, roots, and grains of wheat grown under different levels of zinc.

<p>The data represented are an average of three replicates ± standard deviation.</p

Yield parameters of wheat in response to mycorrhizal inoculation grown under different levels of Zn.

<p>Data were presented as the mean of three replicates followed by the standard deviation (mean ± SD).</p

pH values, electrical conductivity (EC dsm^-1), cations and anions contents (mg/100 g), heavy metal contents (Fe and Zn mg kg^-1), phosphorus contents (P; mg kg^-1), the percentage of organic matter (OM%) and soils texture of 5 sites of cultivated soils.

<p>pH values, electrical conductivity (EC dsm^-1), cations and anions contents (mg/100 g), heavy metal contents (Fe and Zn mg kg^-1), phosphorus contents (P; mg kg^-1), the percentage of organic matter (OM%) and soils texture of 5 sites of cultivated soils.</p

Arbuscular mycorrhizal strategy for zinc mycoremediation and diminished translocation to shoots and grains in wheat - Fig 2

<p><b>(A) Chlorophyll-a, (B) Chlorophyll-b, (C) Carotenoid pigment content as mg g</b>^<b>-1</b><b>FW of leaves of mycorrhized and non-mycorrhized wheat grown at different levels of treatments with zinc are an average of five replicates, the error bars represent the standard error for the means.</b> ANOVA was performed to assess differences between treatment groups, followed by Duncan's multiple-rank comparisons. Media with similar letters are not significantly different according to Duncan's multiple range comparisons.</p