Insecticidal Effect of Labramin, a Lectin—Like Protein Isolated from Seeds of the Beach Apricot Tree,Labramia bojeri, on the Mediterranean Flour Moth,Ephestia kuehniella

Abstract

The objective of this work was to study the insecticidal effect of labramin, a protein that shows lectin—like properties. Labramin was isolated from seeds of the Beach Apricot tree, Labramia bojeri A. DC ex Dubard (Ericales: Sapotaceae), and assessed against the development of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), an important pest of stored products such as corn, wheat, rice, and flour. Results showed that labramin caused 90% larval mortality when incorporated in an artificial diet at a level of 1% (w/w). The presence of 0.25% labramin in the diet affected the larval and pupal developmental periods and the percentage of emerging adults. Treatments resulted in elevated levels of trypsin activity in midgut and fecal materials, indicating that labramin may have affected enzyme—regulatory mechanisms by perturbing peritrophic membranes in the midgut of is. kuehniella larvae. The results of dietary experiments with E. kuehniella larvae showed a reduced efficiency for the conversion of ingested and digested food, and an increase in approximate digestibility and metabolic cost. These findings suggest that labramin may hold promise as a control agent to engineer crop plants for insect resistance.

Status of Insecticide Resistance in Field-collected Populations of Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae)

“…Martinez et al (2012) also generated similar results from the evaluation of the insecticidal potential of a lectin-like protein (labramin) in Ephestia kuehniella. Similar growth patterns in the presence of toxic compounds have been obtained in insects (Farrar et al, 1989;Weeler and Isman, 2001).…”

Identification and characterization of two novel peritrophic membrane (PM) genes in the Chinese mitten crab Eriocheir sinensis that exhibit activity against high-pH stress and Aeromonas hydrophila challenge

“…These unique functions of the PM, as well as its accessibility, make it an attractive target for pest control strategies. It is also believed that alterations to the PM inhibit infection (Kelkenberg, Odman‐Naresh, Muthukrishnan, & Merzendorfer, ; Martinez et al, ). These research results were in agreement with the PM functioning analogously to the vertebrate intestinal mucosa layer (Zhang et al, ).…”

Dietary and phylogenetic correlates of digestive trypsin activity in insect pests

“…They bind reversibly to specific mono-and oligosaccharides and thus affect digestion through binding to food glycoproteins, polysaccharides (chitin) of the peritrophic membrane, or directly to digestive enzymes. Both increased (Martinez et al, 2012) and decreased (Coelho et al, 2007;Ramzi et al, 2013) trypsin activity have been recorded in the gut of insects fed on lectin-containing diets. Unadapted insects also exhibit increased trypsin activity in feces pointing to impaired function of the peritrophic membrane and recycling mechanism for trypsin (Coelho et al, 2007;Martinez et al, 2012).…”

“…Both increased (Martinez et al, 2012) and decreased (Coelho et al, 2007;Ramzi et al, 2013) trypsin activity have been recorded in the gut of insects fed on lectin-containing diets. Unadapted insects also exhibit increased trypsin activity in feces pointing to impaired function of the peritrophic membrane and recycling mechanism for trypsin (Coelho et al, 2007;Martinez et al, 2012). On the other hand, in resistant insects, lectins are more sensitive to proteolytic degradation or have low ligand-binding ability (Coelho et al, 2007).…”