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Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Plants lack specialized mobile immune cells, but they have many defenses at their disposal. These include both constitutive defenses that are constant and enduring in their expression and inducible defense systems that can lead to structural reinforcements at the site of infection or to specialized responses, such as the hypersensitive response or the systemic acquired resistance response. An inducible defense response is one that can be activated above a baseline level in response to exposure to a parasite. This response is usually triggered by the reception of a signal of infection, followed by activation of an intracellular signaling pathway that culminates in increased transcription of immune-related genes.
Environmental Factors Impacting Bioactive Metabolite Accumulation in Brazilian Medicinal Plants
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Camila Fernanda de Oliveira Junkes, Franciele Antonia Neis, Fernanda de Costa, Anna Carolina Alves Yendo, Arthur Germano Fett-Neto
Biotic responses are normally mediated by signaling compounds, such as jasmonic acid (JA), jasmonoyl isoleucine (Ile-JA) and methyl jasmonate (MeJA), synthesized from linolenic or hexadecatrienoic acids starting with lipoxygenase (LOX) activity. JA and related compounds have a key role in regulation of herbivory and wounding responses by modulating global changes in gene expression. Another example of a major biotic signaling compound is salicylic acid (SA) and its methyl analog, methyl salicylate (MeSA), which have been shown to take part in defense signaling against pathogens, leading to systemic acquired resistance (SAR) and providing long-term defense (Heil and Ton, 2008). Both JA and SA may co-participate and cross talk in herbivory and pathogen responses. Ethylene (ET) also has an important role in plant protection, acting as virulence factor of pathogens and signaling compound in disease resistance, depending on the situation (van Loon et al., 2006). The simulation of herbivory by applying mechanical damage can induce the formation of JA and ET (Bailey et al., 2005). Besides, SA or JA exposure triggers events such as production of ROS and increased cytoplasmic Ca2+, which can stimulate certain biochemical reactions and production of secondary metabolites (Lin et al., 2001) (see Table 6.3).
Nucleic Acids
Published in Danilo D. Lasic, LIPOSOMES in GENE DELIVERY, 2019
The world crop (>$1 trillion), which spends over a billion dollars annually on pesticides (which in addition to the toxicity to the environment can damage the ozone layer), loses more than 10% of the crop to various pests. There is an effort to generate transgenic plants which would be resistant to pests due to systemic acquired resistance genes which code for various proteins, such as peroxidases, chitinases, glucanases, ribosome-inactivating proteins, defensins (antimicrobial peptides), lysozymes, and so on. Currently, more than 50 different transgenic maize variations are in field trials. Other crops include rice (inclusion of insecticidal protein against leaf-folder and stem-borer insects), other cereals, and potato in which the production of larger quantities of more-valuable starch is also being engineered.
Electron Beam Irradiated Chitosan elicits enhanced antioxidant properties combating resistance to Purple Blotch Disease (Alternaria porri) in Onion (Allium cepa).
Published in International Journal of Radiation Biology, 2022
Harshvardhan Dattatray Gaikwad, Sunil Govind Dalvi, Shrihari Hasabnis, Penna Suprasanna
Phytopathogens infect their hosts by employing different strategies and, the process of host–plant interaction with biotic stresses is known to involve biomolecular interactions that are critical for the activation of systemic acquired resistance (SAR). Chitosan is involved in the activation of SAR by enhancing the chitinase enzyme, which is the major antifungal candidate reported in many crops (Katiyar et al. 2015; Malerba and Cerana 2019). In the present study, we have applied irradiated chitosan for eliciting the resistance mechanism against a fungal disease in onion through the higher induction of β-1,3-glucanase. Radiation technologies have been shown to induce drastic reduction in average viscosity molecular weight of chitosan due to the breakdown of the biopolymer chain which could result from free radical reactions that may occur after radiation is absorbed upon the material (Mirajkar et al. 2019).
Orobanche foetida resistance in two new faba bean genotypes produced by radiation mutagenesis
Published in International Journal of Radiation Biology, 2018
Sonia Mejri, Yassine Mabrouk, Omrane Belhadj, Mouldi Saidi
Gamma irradiation can induce systemic acquired resistance (SAR) in plants against the pathogens. Breeding for disease resistance is easy when a good source of resistance is available. Unfortunately, this is not the case in faba bean against broomrape, where the only incomplete resistance of complex inheritance has been identified (Maalouf et al. 2011). Resistance identified in faba bean was attributed to mechanisms operating against the establishment of germinated broomrape seeds and inhibiting the penetration through the host tissues as well as hampering the tubercle development (Abbes et al. 2007; Pérez-de-Luque et al. 2010). As a consequence, differences in resistance, caused by diverse mechanisms, which could account for the remaining variation, might be under-represented by the simple scoring of the final number of emerged orobanche shoots.
Efficacy of nano-silicon in the control of chocolate spot disease of Vicia faba L. caused by Botrytis fabae
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Khadiga A. Hasan, Hoda Soliman, Zakaria Baka, Yasser M. Shabana
Different management methods proved to control chocolate spot disease and reduced the losses in faba bean yield worldwide. These include the use of fungicides and bioagents that were widely used and provided effective and reliable disease control measure [6]. Recently, induced resistance of faba bean plants by systemic acquired resistance enhancement was used in controlling chocolate spot diseases [7]. Systemic resistance of host plants reduces the disease severity (DS) without high costs avoiding environmental destructive effects [89,].