Insecticidal action of mammalian galectin‐1‐transfected Arabidopsis thaliana

BACKGROUND Galectins (GALs) are a family of mammalian sugar‐binding proteins specific for β‐galactosides. Our previous studies have shown that the larval development of the diamondback moth ( Plutella xylostella ) is significantly disturbed when fed with recombinant mammalian galectin 1 ( GAL1 ) derived from Escherichia coli. To further explore its applicability, two GAL1‐ overexpressed Arabidopsis [ GAL1 ‐ Arabidopsis (whole plant) and GAL1 ‐ Arabidopsis ‐vas (vascular bundle‐specific)] lines were established for insecticidal activity and mechanism studies. RESULTS The expression level of GAL1 in transgenic Arabidopsis is 1–0.5% ( GAL1 ‐ Arabidopsis ) and 0.08–0.01% ( GAL1 ‐ Arabidopsis ‐vas) of total leaf soluble protein. Survival, body weight, and food consumption significantly decreased in a time‐dependent manner in P. xylostella larvae (with chewing mouthparts) fed on GAL1 ‐ Arabidopsis . The mortality of Kolla paulula (with piercing‐sucking mouthparts and xylem feeder) fed on GAL1 ‐ Arabidopsis ‐vas was also significantly higher than that fed on wild‐type Arabidopsis (WT‐ Arabidopsis ), but was lower than that fed on GAL1 ‐ Arabidopsis . The histochemical structure and results of immunostaining suggested that the binding of GAL1 to the midgut epithelium of P. xylostella fed on GAL1 ‐ Arabidopsis was dose‐ and time‐dependent. Ultrastructural studies further showed the disruption of microvilli, abnormalities in epithelial cells, and fragments of the peritrophic membrane (PM) in P. xylostella larvae fed on GAL1 ‐ Arabidopsis . CONCLUSION The insecticidal mechanism of GAL1 involves interference with PM integrity and suggests that GAL1 is a potential candidate for bioinsecticide development.