Scientists at the John Innes Centre (JIC) have discovered that plants under
aphid attack use calcium as a warning signal. They found that when the
insect feeds on leaves, it triggers the plant to send calcium into damaged
cells. This prompts the plant to signal that an attack is underway, and a
larger amount of calcium is then mobilized from within the cell.

The researchers used electrophysiological monitoring and a
genetically-encoded fluorescent reporter of calcium to show that calcium is
elevated in penetration sites of aphids during the early stages of its
attempt to establish a long-term feeding site. They combined this knowledge
with evaluation of the genetic response to determine that the elevation of
calcium was dependent on specific plant membrane channels.

"Understanding the mechanisms involved in the early stages of feeding may
provide information on how we can stop the aphid in its tracks and prevent
virus transmission," says JIC Professor Saskia Hogenhout.

[www.jic.ac.uk]
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