Monday, August 20, 2012

Do Aphids Photosynethesize?



The biology of aphids is bizarre: they can be born pregnant and males sometimes lack mouths, causing them to die not long after mating. In an addition to their list of anomalies, work published this week indicates that they may also capture sunlight and use the energy for metabolic purposes.

Aphids are unique among animals in their ability to synthesize pigments called carotenoids. Many creatures rely on these pigments for a variety of functions, such as maintaining a healthy immune system and making certain vitamins, but all other animals must obtain them through their diet. Entomologist Alain Robichon at the Sophia Agrobiotech Institute in Sophia Antipolis, France, and his colleagues suggest that, in aphids, these pigments can absorb energy from the Sun and transfer it to the cellular machinery involved in energy production.



Light- induced electron transfer and ATP synthesis in a carotene synthesizing insect

Authors:

1. Jean Christophe Valmalette (a)
2. Aviv Dombrovsky (b,d)
3. Pierre Brat (c)
4. Christian Mertz (c)
5. Maria Capovilla (d)
6. Alain Robichon (d)

Affiliations:

a. IM2NP UMR 7334 CNRS, Université du Sud Toulon Var, P.O. Box 20132, 83957 La Garde CEDEX, France

b. Volcani Center, Institute of Plant Protection, P.O. Box 6, 50250 Bet Dagan, Israel

c. CIRAD UMR QualiSud, 73 rue J.F. Breton, TA B-95/16, 34398 Montpellier CEDEX 5, France

d. UMR7254 INRA/CNRS/UNS, Institut Sophia Agrobiotech, 400 route des Chappes, P. O. Box 167, 06903 Sophia Antipolis, France

Abstract:

A singular adaptive phenotype of a parthenogenetic insect species (Acyrthosiphon pisum) was selected in cold conditions and is characterized by a remarkable apparition of a greenish colour. The aphid pigments involve carotenoid genes well defined in chloroplasts and cyanobacteria and amazingly present in the aphid genome, likely by lateral transfer during evolution. The abundant carotenoid synthesis in aphids suggests strongly that a major and unknown physiological role is related to these compounds beyond their canonical anti-oxidant properties. We report here that the capture of light energy in living aphids results in the photo induced electron transfer from excited chromophores to acceptor molecules. The redox potentials of molecules involved in this process would be compatible with the reduction of the NAD+ coenzyme. This appears as an archaic photosynthetic system consisting of photo-emitted electrons that are in fine funnelled into the mitochondrial reducing power in order to synthesize ATP molecules.

hmmmm.

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