Different antimetabolic effects of related lectins towards nymphal stages of Nilaparvata lugens

Abstract

Insect feeding trials were carried out to determine the effects of a range of mannose-specific lectins on third instar nymphs of the rice brown planthopper (BPH), Nilaparvata lugens. StAl. Dose response curves show that Galanthus nivalis agglutinin (GNA) has the strongest toxic effect of the lectins tested, and is effective at concentrations considerably lower than those previously reported. Narcissus pseudonarcissus agglutinin (NPA) and Allium sativum agglutinin (ASA) exhibit a significant antimetabolic effect towards the insect but were less effective (on a molar basis) than GNA. LCs0 values for GNA, NPA and ASA are approximately 4/zM, 11/zM and >40/zM respectively. These mannose-specific lectins are serologically identical, but differ in the number of subunits per protein molecule; ASA is a dimer, NPA is a trimer and GNA is a tetramer. The results obtained support the hypothesis, that the effectiveness of the mannose-binding lectins as antimetabolites is determined by the number of subunits per molecule. Two N-acetylglucosamine binding lectins, the dimeric Oryza sativa agglutinin (OSA) and the monomeric Urtica dioica agglutinin (UDA), were also tested but at a concentration of 0.1% w/v exhibited no significant antimetabolic effect towards BPH, although the related lectin wheatgerm agglutinin (WGA) has previously been demonstrated to be toxic towards the insect.

Nectar chemistry

“…It belongs to the structurally and evolutionarily conserved protein family of monocotyledon mannose-binding lectins. Other proteins from this family have antibiotic properties, particularly against nematodes and insects with piercing-sucking mouthparts (Hilder et al, 1995;Powell et al, 1995;Rabhé et al, 1995). Because the monocotyledon mannose-binding lectins occur in the families Amaryllidaceae, Alliaceae, Orchidaceae, Araceae, and Liliaceae, Peumans et al (1997) also tested nectar from these families.…”

Tobacco Nectaries Express a Novel NADPH Oxidase Implicated in the Defense of Floral Reproductive Tissues against Microorganisms

“…A Man-binding lectin that accumulated to approximately 150 mg/mL of nectar was identified. This highly conserved protein has antibiotic properties against nematodes and insects with piercing-sucking mouthparts Powell et al, 1995;Rabhé et al, 1995). A second defense-related protein isolated from leek nectar is alliinase (alliin lyase), a pyridoxal phosphate-containing enzyme that produces the chemicals responsible for the pungent odor of Allium plants.…”

The Interactions of Allium sativum Leaf Agglutinin with a Chaperonin Group of Unique Receptor Protein Isolated from a Bacterial Endosymbiont of the Mustard Aphid

“…However, some carbohydrate binding plant lectins, e.g. Galanthus nivalis agglutinin, Phaseolus hemagglutinin, and wheat germ agglutinin have been reported to be able to control homopteran pests (11)(12)(13)(14)(15). We demonstrated previously (16,17) the detrimental effects of the mannose-binding Allium sativum leaf (ASAL) and bulb (ASA) lectins on the growth and development of L. erysimi when provided in an artificial diet bioassay.…”