A Novel Plant Growth–Promoting Agent Mitigates Salt Toxicity in Barley (Hordeum vulgare L.) by Activating Photosynthetic, Antioxidant Defense, and Methylglyoxal Detoxification Machineries

Abstract

Developing and applying a novel plant growth–promoting agent (PGPA; a micronutrient-amino acid chelated compound developed from autolysis yeast cells) in alleviating salt stress toxicity can be the best alternative option environmentally and economically. High-performance liquid chromatography (HPLC) showed that the assembled PGPA is rich in nucleobases than yeast extract (> 56-fold). This study, as a first investigation, was aimed to evaluate PGPA’s potential role in reducing oxidative injury induced by salt stress. Barley (Hordeum vulgare L. cv. Giza 123) plants were grown under non-saline or saline conditions (6.0 and 12.0 dS m−1) with and without PGPA foliar application. The PGPA application mitigated salt-induced oxidative stress by enhancing the activity of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, glutathione peroxidase, and glutathione S-transferase, as well as the content of ascorbate, glutathione, proline, and glycinebetaine. Moreover, PGPA protected salt-stressed plants from the deleterious effects of methylglyoxal by up-regulating the glyoxalase enzymes activity. The PGPA alleviated membrane damage by decreasing reactive oxygen species (ROS) accumulation, lipid peroxidation, protein oxidation, electrolyte leakage, and NADP+ content. The protection of photosynthesis by PGPA was closely associated with the improved chlorophyll fluorescence parameters, leaf water content, membrane stability index, and NADPH content. The PGPA-treated plants also exhibited higher stomatal conductivity together with improved transpiration and photosynthetic rates under saline conditions. Overall, PGPA regulated the antioxidant machinery, glyoxalase system, and photosynthetic capacity, implying that it plays a critical role in salt stress mitigation. Therefore, it could be a useful agent to alleviate the harmful effects of salinity stress.

Enhancement of the Expression of ZmBZR1 and ZmBES1 Regulatory Genes and Antioxidant Defense Genes Triggers Water Stress Mitigation in Maize (Zea mays L.) Plants Treated with 24-Epibrassinolide in Combination with Spermine

“…In addition to enhancing the activities of antioxidant enzymes, EBL and/or Spm foliage applications also contribute to AsA-GSH cycle modulation. Both AsA and GSH play a key role in ROS detoxification [62]. In the present study, when maize plants encounter water shortage environments, EBL and/or Spm treatments significantly meliorated the content of AsA and GSH, suggesting that treated plants could rely on antioxidants to maintain cellular redox homeostasis under stressful conditions.…”

“…MDA is one of the products of cell membrane lipid peroxidation which damages cell membranes, finally leading to electrolyte extravasation and subsequent changes in the EL. The level of MDA and EL, therefore, reflect the degree of cell membrane integrity and are regarded as critical physiological indicators of plant senescence [62]. Our study shows that under drought stress, the application of EBL and/or Spm decreased the MDA and EL levels in the leaves.…”

Co-application of salicylic acid and spermine alleviates salt stress toxicity in wheat: growth, nutrient acquisition, osmolytes accumulation, and antioxidant response

“…Overproduction and buildup of ROS, which result in oxidative damage, can be brought by salt stress (Talaat et al 2022b). In this study, wheat leaves under salt stress produced an excessive amount of H 2 O 2 (Fig.…”

“…Soil salinization has detrimental impacts on plant development, reducing crop yields (Kaya et al 2020;Talaat and Shawky 2022;Talaat et al 2022b). Our results revealed that salt stress significantly (p < 0.05) hindered wheat development (Figs.…”

Plant Growth Stimulators Improve Two Wheat Cultivars Salt-Tolerance: Insights into Their Physiological and Nutritional Responses

“…Osmolyte biosynthesis is critical for maintaining osmotic potential, metabolic activity, and water uptake under saline conditions [ 6 ]. Additionally, enzymatic and non-enzymatic antioxidants can scavenge effectively the excessive reactive oxygen species (ROS) generated during salt stress [ 7 , 8 , 9 , 10 , 11 ]. Ionic status inside the plant cell is also very important for plant salt tolerance because the excess of salt ions in the cytoplasm disrupts ion homeostasis, inhibits plant growth, and affects water transport [ 7 , 12 ].…”