Symbiotic bacteria enable insect to use a nutritionally inadequate diet
- 2 December 2008
- journal article
- Published by The Royal Society in Proceedings. Biological sciences
- Vol. 276 (1658), 987-991
- https://doi.org/10.1098/rspb.2008.1476
Abstract
Animals generally require a dietary supply of various nutrients (vitamins, essential amino acids, etc.) because their biosynthetic capabilities are limited. The capacity of aphids to use plant phloem sap, with low essential amino acid content, has been attributed to their symbiotic bacteria, Buchnera aphidicola, which can synthesize these nutrients; but this has not been demonstrated empirically. We demonstrate here that phloem sap obtained from the severed stylets of pea aphids Acyrthosiphon pisum feeding on Vicia faba plants generally provided inadequate amounts of at least one essential amino acid to support aphid growth. Complementary analyses using aphids reared on chemically defined diets with each amino acid individually omitted revealed that the capacity of the symbiotic bacterium B. aphidicola to synthesize essential amino acids exceeded the dietary deficit of all phloem amino acids except methionine. It is proposed that this shortfall of methionine was met by aphid usage of the non-protein amino acid 5-methylmethionine in the phloem sap. This study provides the first quantitative demonstration that bacterial symbiosis can meet the nutritional demand of plant-reared aphids. It shows how symbiosis with micro-organisms has enabled this group of animals to escape from the constraint of requiring a balanced dietary supply of amino acids.This publication has 35 references indexed in Scilit:
- A Diurnal Component to the Variation in Sieve Tube Amino Acid Content in WheatPlant Physiology, 2008
- Symbiosis as an adaptive process and source of phenotypic complexityProceedings of the National Academy of Sciences of the United States of America, 2007
- Characterization of a membrane‐bound aminopeptidase purified from Acyrthosiphon pisum midgut cellsThe FEBS Journal, 2006
- Molecular Interactions between Bacterial Symbionts and Their HostsCell, 2006
- Sweet problems: insect traits defining the limits to dietary sugar utilisation by the pea aphid,Acyrthosiphon pisumJournal of Experimental Biology, 2006
- Phloem amino acids and the host plant range of the polyphagous aphid, Aphis fabaeEntomologia Experimentalis et Applicata, 2003
- Quantifying the symbiont contribution to essential amino acids in aphids: the importance of tryptophan for Uroleucon ambrosiaePhysiological Entomology, 2002
- N content of phloem and xylem exudates during the transition to flowering in Sinapis alba and Arabidopsis thalianaPlant, Cell & Environment, 2001
- Plant penetration by pea aphids (Acyrthosiphon pisum) of different plant rangeEntomologia Experimentalis et Applicata, 1998
- Differences in amino acid requirements between two biotypes of the pea aphid, Acyrthosiphon pisumCanadian Journal of Zoology, 1985