A Horizontal Gene Transfer Led to the Acquisition of a Fructan Metabolic Pathway in a Gall Midge

Abstract

the horizontally transferred levanase genes in the Hessian fly resulted in a shift in the endogenous carbohydrate metabolic pathway for utilizing fructans.

Insect derived extra oral GH32 plays a role in susceptibility of wheat to Hessian fly

“…1a). Sequence alignment of the Biotype L MdesGH32 and JBrowse annotated sequence from the draft Biotype GP genome 32 revealed 98.5% and 97.9% nucleotide and protein sequence identity, respectively, identified as MDL-9 31 . A putative secretory signal peptide sequence of 19 amino acids at the N-terminus was predicted by SignalP (Fig.…”

“…GH32s from insects have diverse enzyme activities (CAZy database). These enzymes are expressed during various stages of insect development and play a crucial role in the digestion and metabolism of ingested plant-derived cell wall materials within the gut 8,31,41 . MdesGH32, identified from one of the most virulent Hessian fly Biotype L larvae, encodes for a GH32-family protein.…”

“…Of ten putative GH32 proteins (MDL1-10) identified recently from the Hessian fly biotype GP 41 , MdesGH32 shares a 98% identity with MDL-9. A recent study on the similarity and proximity of the multiple MDL genes on a single scaffold suggests that there may have been a single HGT event for GH32 followed by duplications over the course of evolution 31 . Our phylogenetic result for Biotype L suggests that the Hessian fly genome possibly gained MdesGH32 from its gut-associated microbial symbionts as a result of direct HGT or duplication from a single HGT event, during evolution.…”

“…Here, we report not only the expression of MdesGH32, a gene belonging to the GH32 family in Hessian fly larvae feeding on susceptible wheat, but also presence of the larval protein in the feeding sites on the host plant. The homolog of this gene in the Great Plains (GP) biotype of Hessian fly is one of a group of ten Mayetiola destructor levanase (MDL) genes identified recently to belong to the GH32 family 31 . With the MDL proteins being demonstrated to have levanase/inulinase/sucrase activities, and present in digestive tissues within the Hessian fly larvae 31 , our results complement and extend the previous work to strongly support the possible involvement of extra-oral insect PCWDEs in breakdown of wheat cell wall architecture and carbohydrate components by Hessian fly, and elucidate the molecular mechanism by which a nutrient sink is established.…”

“…The homolog of this gene in the Great Plains (GP) biotype of Hessian fly is one of a group of ten Mayetiola destructor levanase (MDL) genes identified recently to belong to the GH32 family 31 . With the MDL proteins being demonstrated to have levanase/inulinase/sucrase activities, and present in digestive tissues within the Hessian fly larvae 31 , our results complement and extend the previous work to strongly support the possible involvement of extra-oral insect PCWDEs in breakdown of wheat cell wall architecture and carbohydrate components by Hessian fly, and elucidate the molecular mechanism by which a nutrient sink is established. Further molecular and functional characterization of this PCWDE could reveal possible virulence mechanisms employed by Hessian fly during compatible plant-insect interactions and lead to further downstream applications for efficient management and control of this and other devastating dipteran insect pests.…”