www.checkbiotech.org ; www.raupp.info ; www.czu.cz


Constantly beset by pests, subjected to harsh soils, and buffeted by
unfriendly weather, higher plants have evolved defense mechanisms to protect
themselves against stress, January 2006 .

One such immune response involves the plant hormone jasmonic acid (JA),
which controls the expression of target genes, which, in turn, are produced
during tissue damage. It is thought that these target genes play a direct
role in destroying insect pests.

Hui Chen, of the Department of Energy Plant Research Laboratory, and
colleagues test this hypothesis in ?Jasmonate-inducible plant enzymes
degrade essential amino acids in the herbivore midgut,? an article that
appears in the December 27, 2005 issue of the Proceedings of the National
Academy of Sciences.

Through tests on the gut Manduca sexta larvae fed on tomato plants,
researchers found that two JA-induced proteins, arginine and threonine
deaminase, act in larval midgut to break down amino acids and thus affect
insect performance. Moreover, transgenic plants over-expressing arginase
were found to be more resistant to M. sexta larvae, and this effect was
correlated with reduced levels of midgut arginine.

Read the complete article at
[www.pnas.org]

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