The effect of nano silica (50 mL L⁻¹) and melatonin (75 µM) individually or in combination in foliar applications on the morphophysiological, biochemical and yield properties of pea plants under salinity stress conditions was evaluated. Salt stress caused a remarkable decrease in the growth and yield characteristics; for example, the plant dry weight, plant height, number of flowers plant⁻¹, number of pods plant⁻¹, weight of 100 green seeds and protein concentration in the pea plants during both seasons were decreased compared with the control. Similarly, their physiobiochemical characteristics were negatively affected; chlorophyll a, chlorophyll b and the relative water content (RWC) were significantly reduced in the stressed pea plants. However, malondialdehyde (MDA), hydrogen peroxide, the electrolyte leakage (EL%), super oxide and the antioxidant components (catalase (CAT), superoxide dismutase (SOD), peroxidase (POX) and total phenolic compounds) were significantly increased when the plants were under salt stress compared with the control plants. On the other hand, the foliar application of nano silica and melatonin individually or in combination enhanced the physiobiochemical characteristics, morphological characteristics and yield of the stressed pea plants. The best treatment was the combination treatment (nano silica + melatonin), which caused significant increases in the plant dry weight, plant height, number of flowers and pods plant⁻¹, weight of 100 green seeds, protein concentration, chlorophyll concentrations and RWC in the stressed pea plants. Additionally, the combination treatment significantly decreased the EL%, MDA, O₂⋅− and H₂O₂ and adjusted the upregulation of the antioxidant enzymes, proline and total phenolic compounds in the stressed plants compared with the stressed untreated pea plants. Generally, it can be suggested that the co-application of nano silica (50 mL L⁻¹) + melatonin (75 µM) plays a positive role in alleviating the adverse impacts of salinity on pea plants by modifying the plant metabolism and regulating the antioxidant defense system as well as scavenging reactive oxygen species.

Eight wheat cultivars, Sakha-94, Giza-171, Sids-1, Sids-12, Sids-13, Shandweel-1, Misr-1, and Misr-2, were evaluated for leaf rust at the seedling and adult stages in the 2021 and 2022 seasons. Biochemical, histological, and genetic analyses were performed to determine the link between cultivars that were either sensitive or resistant to the disease. Misr-2 and Giza-171 cultivars had the highest levels of resistance to leaf rust races in 2021 (LTCGT, STSJT, and TTTST) and 2022 (MBGJT, TTTKS, and TTTTT) at the seedling stage. However, at the adult stage, Sakha-94, Giza-171, Misr-1, and Misr-2 cultivars had the highest levels of resistance; consequently, they had the lowest final disease severity and the lowest values of AUDPC. The correlation between the seedling reaction and adult reaction was non-significant, with values of 0.4401 and 0.4793 in the 2021 and 2022 seasons, respectively. Throughout the biochemical, histological, and genetic analyses, it was observed that catalase, peroxidase, and polyphenol oxidase activities significantly increased in the resistant cultivars. The discoloration of superoxide (O₂-) and hydrogen peroxide (H₂O₂) significantly decreased in resistant and moderately resistant wheat cultivars (Sakha-94, Giza-171, Misr-1, and Misr-2); higher hydrogen peroxide (H₂O₂) and superoxide (O₂-) levels were recorded for the susceptible cultivars compared to the resistant cultivars. Molecular markers proved that the Lr50 gene was detected in the resistant cultivars. Puccinia triticina infections negatively affected most histological characteristics of flag leaves, especially in susceptible cultivars. The thickness of the blade (µ), the thickness of the upper and lower epidermis (UE and LE), the thickness of mesophyll tissue (MT), and bundle length and width in the midrib were decreased in susceptible cultivars such as Sids-1, Sids-13, and Shandwel-1 compared with resistant cultivars.

This study aimed to evaluate the role of Bacillus megaterium and Arbuscular Mycorrhizal Fungi (AMF) in increasing salt tolerance in wheat associated with physio-biochemical and anatomical characteristics. Results displayed that salinity stress (6 dS m−1 NaCl) significantly decreased (p ≤ 0.05) nitrogen, phosphorus, potassium, chlorophyll a and b content, maximum quantum yield of PSII and relative water content (RWC) in both seasons. Additionally, the anatomical characteristics of flag leaf were harmfully affected. However, malondialdehyde (MDA), superoxide (O2•−), hydrogen peroxide (H2O2) and electrolyte leakage (EL) were increased significantly (p ≤ 0.05) in both seasons. Also, proline and total phenolic compounds were increased significantly in the stressed seedlings. On the other hand, inoculation of grains with B. megaterium and AMF significantly augmented nitrogen, phosphorus, potassium, chlorophyll a and b content, maximum quantum yield of PSII and relative water content as well as modified the antioxidant defense system such as catalase, peroxidase, proline and total phenolic compounds in both seasons. Also, the anatomical structures of flag leaves were significantly improved in the stressed wheat seedlings under treatment with B. megaterium and AMF in comparison to stressed uninoculated seedlings. Generally, application of B. megaterium and AMF can improve the physio-biochemical and anatomical characteristics of wheat seedlings under salinity conditions.

The information presented in this study suggests that Trichoderma could be used as a secure, environmentally acceptable, and efficient biocontrol agent for many crop species. The family Hypocreaceae includes a variety of free-living fungi under the genus Trichoderma (class Ascomycetes), which live in different ecosystems in a wide range of climatic zones and can be found all over the world. This paper provides a summary of the biological control activity of Trichoderma spp. and highlights recent developments in delineating Trichoderma’s role in biochemical and molecular processes in the rhizosphere, as well as its ecological significance and advantages of symbiosis with the plant host in terms of physiological and biochemical mechanisms. We examined the interactions between Trichoderma harzianum (T. harzianum) strains and some soilborne plant pathogens (Phylaspora rhodia, Diaporthe citri, and Nattrassia mangiferae) in vitro and in vivo. All T. harzianum strains tested antagonistic and inhibited plant pathogenic and wood decay fungi growth on the PDA medium. When it was tested, the strain TII was more muscular, so it was a better competitor against the wood decay pathogens under the study.