Can Plant Lectins Help to Elucidate Insect Lectin-Mediated Immune Response?

Abstract

Lectins are carbohydrate-binding proteins that recognize and selectively bind to specific sugar structures. This group of proteins is widespread in plants, animals, and microorganisms, and exerts a broad range of functions. Many plant lectins were identified as exogenous stimuli of vertebrate immunity. Despite being the largest and most diverse taxon on earth, the study of lectins and their functions in insects is lagging behind. In insects, research on lectins and their biological importance has mainly focused on the C-type lectin (CTL) family, limiting our global understanding of the function of insect lectins and their role in insect immunity. In contrast, plant lectins have been well characterized and the immunomodulatory effects of several plant lectins have been documented extensively in vertebrates. This information could complement the missing knowledge on endogenous insect lectins and contribute to understanding of the processes and mechanisms by which lectins participate in insect immunity. This review summarizes existing studies of immune responses stimulated by endogenous or exogenous lectins. Understanding how lectins modulate insect immune responses can provide insight which, in turn, can help to elaborate novel ideas applicable for the protection of beneficial insects and the development of novel pest control strategies.

Binding of Orysata lectin induces an immune response in insect cells

“…These effects resemble to the immune effect of encapsulation, a process in which hemocytes gather together and enclose a pathogen by making a capsule‐like structure, thereby limiting its mobility, development and/or proliferation (Ishihara et al ., 2017), suggesting this lectin might have immunomodulatory effects on insect cells. The immunomodulatory activity of plant lectins is often associated with their interaction with glycan moieties present on cell surfaces (reviewed by Chen et al ., 2021). Such interactions can result in a signal transduction, which triggers the effector mechanisms involved in the immune response (reviewed by Souza et al ., 2013; Chen et al ., 2021).…”

“…The immunomodulatory activity of plant lectins is often associated with their interaction with glycan moieties present on cell surfaces (reviewed by Chen et al ., 2021). Such interactions can result in a signal transduction, which triggers the effector mechanisms involved in the immune response (reviewed by Souza et al ., 2013; Chen et al ., 2021). In this study, Orysata was observed to readily bind to the cell surface of D. melanogaster S2 cells, possibly through interaction with the glycans of the glycoproteins on the cell surface.…”

Insights into protein fucosylation in insects

“…In such strategies, carbohydrate binding proteins, or lectins, with a specificity for fucosylated glycans, e.g., F-type lectins (Vasta et al 2017, Vasta & Feng 2020) could be used to disrupt the insect immune response against parasitoids or fungal or microbial agents. The role of lectins in the insect immune system have recently been summarized (Chen et al 2021, Ming et al 2023. In addition to the model D. melanogaster, the study of honeybees is gaining more attention as its royal jelly is a natural antimicrobial agent (Fratini et al 2016), while its venom is allergenic (Pucca et al 2019).…”

Plant Responses to Herbivory, Wounding, and Infection

“…Lectins are proteins found naturally in most plants; they enhance plant immunity during plant-insect interactions through the release of cytokines and other effectors. However, the mechanism of plant lectin production in response to insect or pathogen attacks remains unclear [142].…”