Journal Article

Physical and chemical interactions between aphids and plants

Will, Torsten, van Bel, Aart J. E.

2006

Overview

Aphids feed from sieve tubes deep inside the host plant. Therefore, aphids must be able to recognize their host plant(s) and to direct their stylets which must be long and thin enough to reach and puncture the sieve tubes at a particular site. Sieve tubes in angiosperms are longitudinal arrays of sieve element/companion cell modules which are highly sensitive to disturbance of any kind. The sieve tubes dispose of elaborate sealing mechanisms such as protein plugging and callose sealing which are triggered by a rise in calcium in the sieve tubes. Aphids seem to have developed a range of physical and chemical measures to limit the amount of calcium influx in response to stylet puncturing. Loss of sieve-element turgor pressure induced by stylet insertion is minimized by the minute stylet volume. Turgor-dependent Ca2+ influx, possibly mediated by mechano sensitive Ca2+ channels, must therefore be limited. The components of the sheath and watery saliva play a pivotal role in establishing the physical and chemical constraints on the rise of calcium. Most likely, sheath saliva prevents the influx of calcium from the apoplast by sealing the stylet puncture site while watery saliva may prevent plugging and sealing of sieve plates by potential interaction with SE sap ingredients.

• Publisher: Oxford University Press,Oxford Publishing Limited (England)
• Subject: anatomy & histology / Animals / Aphidoidea / Aphids / Aphids - anatomy & histology / Aphids - chemistry / Aphids - physiology / aphid–plant interaction / Calcium / Calcium - metabolism / Calcium - physiology / callose / Chemical interactions / chemistry / defense mechanisms / Entomology / Focus Papers: Phloem–Insect Interaction / Glucans / Glucans - physiology / host plants / insect pests / Insect Proteins / Insect Proteins - metabolism / Insect Proteins - physiology / ion transport / literature reviews / Mechanotransduction, Cellular / metabolism / Models, Biological / parasitology / Phloem / physiology / Plant cells / plant pests / Plant physiology / Plant Proteins / Plant Proteins - metabolism / Plant Proteins - physiology / Plant Stems / Plant Stems - anatomy & histology / Plant Stems - parasitology / plant-insect relations / Plants / Plants - chemistry / Plants - metabolism / Plants - parasitology / resistance mechanisms / Saliva / Saliva - chemistry / Saliva - physiology / sap / sheath saliva / Sieve elements / Sieve plates / Sieve tubes / stylet / suppression of plant defence / turgor / watery saliva / wound reaction