Functional Characterization of HFR1, a High-MannoseN-Glycan-Specific Wheat Lectin Induced by Hessian Fly Larvae    

Abstract

We previously cloned and characterized a novel jacalin-like lectin gene from wheat (Triticum aestivum) plants that responds to infestation by Hessian fly (Mayetiola destructor) larvae, a major dipteran pest of this crop. The infested resistant plants accumulated higher levels of Hfr-1 (for Hessian fly-responsive gene 1) transcripts compared with uninfested or susceptible plants. Here, we characterize the soluble and active recombinant His 6 -HFR1 protein isolated from Escherichia coli. Functional characterization of the protein using hemagglutination assays revealed lectin activity. Glycan microarray-binding assays indicated strong affinity of His 6 -HFR1 to Mana1-6(Mana1-3)Man trisaccharide structures. Resistant wheat plants accumulated high levels of HFR1 at the larval feeding sites, as revealed by immunodetection, but the avirulent larvae were deterred from feeding and consumed only small amounts of the lectin. Behavioral studies revealed that avirulent Hessian fly larvae on resistant plants exhibited prolonged searching and writhing behaviors as they unsuccessfully attempted to establish feeding sites. During His 6 -HFR1 feeding bioassays, Drosophila melanogaster larvae experienced significant delays in growth and pupation, while percentage mortality increased with progressively higher concentrations of His 6 -HFR1 in the diet. Thus, HFR1 is an antinutrient to dipteran larvae and may play a significant role in deterring Hessian fly larvae from feeding on resistant wheat plants.

Laticifers in mulberry exclusively accumulate defense proteins related to biotic stresses

“…They were all possible defense proteins against insects or microorganisms ( Kitajima and Sato 1999;Ma et al 2010;Subramanyam et al 2008;van Loon et al 2006), which is consistent with the idea that laticifers are specialized for defense against biotic stresses (Kitajima et al 2010(Kitajima et al , 2012Konno 2011). In the unlignified tissue laticifers, one of the galactosebinding lectins (bands 6 and 7) and PR-1 (band 11) were Figure 1.…”

Mechanisms of plant defense against insect herbivores

“…69 Expression of a mannose-binding jacalin-like lectin called Hessian fly, Mayetiola destructor (Say) responsive protein 1 (HFR1), and two chimerolectin-like proteins called HFR2 and HFR3 have been reported to be induced by the larvae of Hessian fly, M. destructor in wheat. 70,71 Differences in feeding behavior of insects results in expression of different lectins, e.g., larvae of the fall armyworm, S. frugiperda induced HFR2, but not HFR3 expression while the phloem-feeding bird cherry-oat aphid, Rhopalosiphum padi Koch, induced HFR3 and HFR2, but latter was expressed much later (12 d) than the former (24 h). 70,72 Several jasmonate-inducible lectins are expressed in leaf tissues of monocots such as rice, barley, wheat, rye, and maize.…”

Binding Properties of the N-Acetylglucosamine and High-Mannose N-Glycan PP2-A1 Phloem Lectin in Arabidopsis

“…Aliquots (70 mL) of PP2-A1-His 6 at the appropriate concentration were applied to each well of the printed microarray. The binding of PP2-A1-His 6 to specific glycans was detected and quantified as described previously (Subramanyam et al, 2008), except that recombinant PP2-A1-His 6 was detected with a commercial antibody against the His 6 tag. Binding was quantified by fluorescence techniques, and the data are expressed as mean numbers of relative fluorescence units for the replicates for each glycan represented on the array.…”