Proton gradient mediates hemolymph trehalose influx into aphid bacteriocytes
Mana Iwata1, Mayu Yoshinaga1, Kosuke Mizutani2
1College of Agriculture, Ibaraki University, Ami, Inashiki, Ibaraki, Japan.
Archives of Insect Biochemistry and Physiology
|October 7, 2022
Summary
Aphids
Area of Science:
- Microbiology
- Insect Physiology
- Symbiotic Relationships
Background:
- Aphids rely on Buchnera aphidicola endosymbionts for essential amino acids.
- Buchnera obtains sugars from the aphid hemolymph, but sugar uptake mechanisms are poorly understood.
- Trehalose is the primary sugar in Acyrthosiphon pisum hemolymph.
Purpose of the Study:
- To investigate the mechanism of trehalose transport into aphid bacteriocytes.
- To identify and characterize the trehalose transporter involved in sugar uptake by Buchnera.
- To elucidate how Buchnera acquires its carbon source from the host hemolymph.
Main Methods:
- Characterization of the trehalose transporter Ap_ST11 using Xenopus oocyte expression system.
- Measurement of hemolymph trehalose concentration using a fluorescent sensor.
- Analysis of trehalose transport kinetics and dependence on proton gradients.
Main Results:
- Trehalose is transported into bacteriocytes via specific trehalose transporters, including Ap_ST11.
- Ap_ST11 functions as a proton-dependent transporter with a high Km value.
- Trehalose uptake does not occur via facilitated diffusion, indicating active transport.
Conclusions:
- Trehalose influx into aphid bacteriocytes is mediated by proton-driven secondary active transport.
- This mechanism ensures Buchnera obtains essential sugars for survival and amino acid synthesis.
- The study reveals a novel pathway for nutrient exchange in aphid-Buchnera symbiosis.
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