Nano-selenium enhances melon resistance to Podosphaera xanthii by enhancing the antioxidant capacity and promoting alterations in the polyamine, phenylpropanoid and hormone signaling pathways

Abstract

Powdery mildew is one of the main problematic diseases in melon production, requiring the use of chemical pesticides with disease-resistant cultivars for control. However, the often rapid acquisition of fungicidal resistance by mildew pathogens makes this practice unsustainable. The identification of crop treatments that can enhance resistance to powdery mildew resistance is therefore important to reduce melon crop attrition. This study indicates that the application of Nano-Se can reduce the powdery mildew disease index by 21–45%. The Nano-Se treatment reduced reactive oxygen species (ROS) and malondialdehyde (MDA) accumulation, with increases in glutathione (GSH), proline and 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH). Increases were also observed in the activities and transcriptional levels of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD). Assays with four different cultivars of melon with differing levels of mildew resistance demonstrated that relative to the control, the Nano-Se treatment resulted in larger responses to mildew infection, including increases in the levels of putrescine (PUT; 43–112%) and spermine (SPM; 36–118%), indoleacetic acid (IAA; 43–172%) and salicylic acid (SA; 24–73%), the activities of phenylalanine ammonium lyase (PAL), trans-cinnamate 4-hydroxylase (C4H) and 4-coumarate: Co A ligase (4CL) of the phenylpropanoid pathway (22–38%, 24–126% and 19–64%, respectively). Key genes in the polyamine and phenylpropanoid pathway were also upregulated. These results indicate that the foliar application of Nano-Se improved melon defenses against powdery mildew infection, with a significant reduction in mildew disease development. Graphical Abstract

Magnesium oxide nanoparticles reduce clubroot by regulating plant defense response and rhizosphere microbial community of tumorous stem mustard (Brassica juncea var. tumida)

“…Numerous studies have shown that nanomaterials can significantly promote plant growth ( Arora et al, 2012 ; Nair, 2016 ), and its mechanism of action is multifaceted, including enhancing photosynthesis ( Liu et al, 2023 ; Mehmood et al, 2023 ), improving the leaf or rhizosphere microbial communities ( Karnwal et al, 2023 ; Liu et al, 2023 ), alleviating oxidative stress and enhancing antioxidant enzyme activity ( Wu et al, 2023 ), and increasing the availability of nutrients in plants ( Ahmed et al, 2022 ), regulating plant hormones and metabolism ( Kang et al, 2023 ), and so on. The results of this study was consistent with part of previous studies.…”

“… Ahmed et al (2022) demonstrated that chitosan-iron nanocomposite controlled bacterial leaf blight by regulating the defense response and nutritional status of rice plants. Kang et al (2023) proved that nano-selenium enhances melon resistance to Podosphaera xanthii by enhancing the antioxidant capacity and promoting hormone signaling pathways. This study found that MgO NPs treatment significantly increased SA content in the root of tumorous stem mustard, and also significantly increased the antioxidant enzyme activity ( Figure 3 ), which was similar to the results of those studies.…”

“…Some strains in Variovorax and Bosea also exhibited the ability to promote plant growth and combat plant pathogens (Bruisson et al, 2019;Khoury et al, 2021;Ma et al, 2023). Other genera of microorganisms, such as Candidatus_Koribacter, Nitrospira (Kang et al, 2023), which were reported by Saraiva et al (2020) to be the dominant in soils with less severe clubroot disease, were significantly enriched after the application of MgO NPs (2,500 mg/L) compared with CK (Supplementary Table S2).…”

Nano-Food Farming: Toward Sustainable Applications of Proteins, Mushrooms, Nano-Nutrients, and Nanofibers

“…Under biotic stress that resulted from Xanthomonas albilineans infection, nano-Se supported the growth of sugarcane as an eco-fungicide and improved the juice quality [202]. The suggested mechanism of nano-Se for plant disease resistance involves enhancing the capacity of antioxidants, inducing the pathway of jasmonic acid, reducing the accumulation of ROS and H 2 O 2 , and promoting the pathways for phytohormones signaling [171,202,210]. Many studies have confirmed the role of nano-Se in inducing the resistance of crops to phytopathogens such as Botrytis cinerea in cucumber [211], spot blotch disease in wheat [212], Podosphaera xanthii in melon [210], Fusarium-induced wilt disease in lettuce [209], and Alternaria leaf spot disease in the common bean [53].…”

“…The suggested mechanism of nano-Se for plant disease resistance involves enhancing the capacity of antioxidants, inducing the pathway of jasmonic acid, reducing the accumulation of ROS and H 2 O 2 , and promoting the pathways for phytohormones signaling [171,202,210]. Many studies have confirmed the role of nano-Se in inducing the resistance of crops to phytopathogens such as Botrytis cinerea in cucumber [211], spot blotch disease in wheat [212], Podosphaera xanthii in melon [210], Fusarium-induced wilt disease in lettuce [209], and Alternaria leaf spot disease in the common bean [53]. Along with the mitigation of stress, other benefits that have been reported due to nano-Se in farming include nano-biofortification [204,205], improving the quality and shelf life of harvested crops [213], and mitigation of abiotic stresses, including salinity [214], heavy metals [215], and drought [216].…”