Genome-wide survey of HMA gene family and its characterization in wheat (Triticum aestivum).

Background: Abiotic stresses, particularly drought and heavy metal toxicity, have presented a significant risk to long-term agricultural output around the world. Although the heavy-metal-associated domain (HMA) gene family has been widely explored in Arabidopsis and other plants, it has not been thoroughly studied in wheat (Triticum aestivum). This study was proposed to investigate the HMA gene family in wheat. Methods: To analyze the phylogenetic relationships, gene structure, gene ontology, and conserved motifs, a comparative study of wheat HMA genes with the Arabidopsis genome was performed. Results: A total of 27 T. aestivum proteins belonging to the HMA gene family were identified in this study, with amino acid counts ranging from 262 to 1,071. HMA proteins were found to be grouped into three subgroups in a phylogenetic tree, and closely related proteins in the tree showed the same expression patterns as motifs found in distinct subgroups. Gene structural study elucidated that intron and exon arrangement differed by family. Conclusion: As a result, the current work offered important information regarding HMA family genes in the T. aestivum genome, which will be valuable in understanding their putative functions in other wheat species.

Appraisal of foliar spray of iron and salicylic acid under artificial magnetism on morpho-physiological attributes of pea (Pisum sativum L.) plants.

The appraisal of foliar treatment of iron (Fe) and salicylic acid (SA) on plant under artificial magnetism is very crucial in understanding its impact on growth and development of plants. The present study was designed to document the potential role of Fe and SA on pea (Pisum sativum L.) Matore variety exposed to different magnetism treatments (geomagnetism and artificial magnetism). Thus a pot experiment was conducted using Completely Randomized Design under factorial with three replicates. Various artificial magnetic treatment were applied in pots prior to sowing. Further, 15 days germinated pea seedlings were foliarly supplemented with 250 ppm Fe and 250µM SA, moreover after 20 days of foliar fertilization plants were harvested to analyze and record various morpho-physiological attributes. Data elucidate significant variations in pea plants among different treatments. Artificial magnetism treatments in combination with foliar application of Fe and SA significantly improved various growth attributes (root and shoot length, fresh and dry weights of root and shoot, leaf area), photosynthetic pigments (Chl a, b and carotenoids) and the contents of soluble sugars. However, oxidative stress (H2O2 and MDA) enhanced under different magnetism treatment but foliar application of Fe and SA hampered the production of reactive oxygen species thereby limiting the concentration of H2O2 and MDA in plant tissues. Furthermore the accumulation of nutrients (iron, potassium and nitrate) profoundly increased under artificial magnetism treatment specifically under Fe and SA foliar treatment excluding nitrate where Fe foliar treatment tend to limit nitrate in plant. Consequently, the present research interestingly highlights progressive role of Fe and SA foliar treatment on pea plants under artificial magnetism. Thus, foliar supplementation may be suggested for better growth and development of plants combined with magnetic treatments.

Oxidative stress tolerance potential of milk thistle ecotypes after supplementation of different plant growth-promoting agents under salinity.

The aim of the present work was to evaluate the effect of different plant growth promoters (PGPs) such as ascorbic acid (500 µM), thiourea (250 µM) and moringa leaf extract (3%) to mitigate salinity stress (120 mM NaCl) in four different milk thistle [Silybum marianum (L.) Gaertn.] ecotypes from Faisalabad (FSD), Gujranwala (GUJ), Kallar Kahar (KK), and Quetta (QTA) under field conditions for two years (2017-2018). In the present study, oxidative stress indicators such as malondialdehyde (MDA) and hydrogen peroxide (H2O2) and activities of different antioxidant enzymes and levels of non-enzymatic antioxidants were significantly differed among ecotypes, salinity, and PGPs. Supplementation with ascorbic acid and moringa leaf extract improved antioxidant defense machinery during the acclimation process against salinity, and milk thistle ecotypes represent their background of ecological zones and inherent tendency to face and confronting stress with improving antioxidant levels to a significant extent in varying ways. Ecotypic variations showed that QTA ecotype Followed by FSD, GUJ, and KK had more antioxidant capacity, with minimum reactive oxygen species production. Interestingly, the correlation data revealed that MDA and H2O2 had a positive correlation with each other and showed a negative correlation with all the enzymatic and non-enzymatic antioxidants.

Fe toxicity in plants: Impacts and remediation.

Fe is the fourth abundant element in the earth crust. Fe toxicity is not often discussed in plant science though it causes severe morphological and physiological disorders, including reduced germination percentage, interferes with enzymatic activities, nutritional imbalance, membrane damage, and chloroplast ultrastructure. It also causes severe toxicity to important biomolecules, which leads to ferroptotic cell death and induces structural changes in the photosynthetic apparatus, which results in retardation of carbon metabolism. However, some agronomic practices like soil remediation through chemicals, nutrients, and organic amendments and some breeding and genetic approaches can provide fruitful results in enhancing crop production in Fe-contaminated soils. Some quantitative trait loci have been reported for Fe tolerance in plants but the function of underlying genes is just emerging. Physiological and molecular mechanism of Fe uptake, translocation, toxicity, and remediation techniques are still under experimentation. In this review, the toxic effects of Fe on seed germination, carbon assimilation, water relations, nutrient uptake, oxidative damages, enzymatic activities, and overall plant growth and development have been discussed. The Fe dynamics in soil rhizosphere and role of remediation strategies, that is, biological, physical, and chemical, have also been described. Use of organic amendments, microbe, phytoremediation, and biological strategies is considered to be both cost and environment friendly for the purification of Fe-contaminated soil, while to ensure better crop yield and quality the manipulation of agronomic practices are suggested.

Exogenous Application of Salicylic Acid and Hydrogen Peroxide Ameliorate Cadmium Stress in Milk Thistle by Enhancing Morpho-Physiological Attributes Grown at Two Different Altitudes.

Cadmium (Cd+2) is a potential and widespread toxic environmental pollutant, mainly derived from a rapid industrial process that has inhibitory effects on growth, physiological, and biochemical attributes of various plant species, including medicinal plants such as Silybum marianum L. Gaertn commonly known as milk thistle. Plant signaling molecules, when applied exogenously, help to enhance/activate endogenous biosynthesis of potentially important signaling molecules and antioxidants that boost tolerance against various abiotic stresses, e.g., heavy metal stress. The present study documented the protective role of salicylic acid (SA;0.25 µM) and hydrogen peroxide (H2O2; 10 µM) priming, foliar spray, and combinational treatments in reducing Cd+2 toxicity (500 µM) in milk thistle grown at two diverse ecological zones of Balochistan Province of Pakistan i.e., Quetta (Qta) and Turbat (Tbt). The morpho-physiological and biochemical attributes of milk thistle were significantly affected by Cd+2 toxicity; however, priming and foliar spray of SA and H2O2 significantly improved the growth attributes (root/shoot length, leaf area, and root/shoot fresh and dry weight), photosynthetic pigments (Chl a, b, and carotenoids) and secondary metabolites (Anthocyanin, Soluble phenolics, and Tannins) at both altitudes by suppressing the negative impact of Cd+2. However, the oxidative damage parameters, i.e., MDA and H2O2, decreased astonishingly under the treatment of signaling molecules, thereby protecting membrane integrity under Cd+2 stress. The morphological variations were profound at the low altitude (Tbt) as compared to the high altitude (Qta). Interestingly, the physiological and biochemical attributes at both altitudes improved under SA and H2O2 treatments, thus hampered the toxic effect of Cd+2. These signaling compounds enhanced tolerance of plants under heavy metal stress conditions with the consideration of altitudinal, and ambient temperature variations remain to be the key concerns.