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

Plants respond to the attack by herbivores by producing an array of chemical
and physical defenses aimed to fend off aggressors and reduce the amount of
damage inflicted, September 2006.

However, the interaction between the plant and its assailants is highly
dynamic, and as survival is as stake, herbivores are under strong selection
pressure to evolve mechanisms that evade the plant defense systems. Could
the development of tolerance to the enemy, acquired by minimizing the effect
of defoliation by insect pests on the fitness of the plant, be a solution to
the problem?

Scientists at the Max Planck Institutes in Jena and Postdam, and in the
Research Centre in Jülich, Germany, report on the discovery of a gene,
GAL83, the beta-subunit of a SNF-1 related kinase in tobacco (Nicotiana
attenuata) plants. The researchers noted that expression of GAL83 was
markedly reduced in young leafs attacked by tobacco hornworm larvae (Manduca
sexta), and that silencing of the gene in the leaves increased the
translocation of carbon from leaves to roots, a less vulnerable part of the
plant.

Increasing root reserves at an early stay of development prolongs flowering,
and allows the plant to invest the saved sugars in seed formation after the
larvae pupate and no longer represent a threat. Down-regulation of GAL83 in
transgenic tobacco plants had the same effects on sugar transport to roots
as insect attack on wild-type plants.

To read the abstract of ?SNF-related kinases allow plants to tolerate
herbivory by allocating carbon to roots? published in the Proceedings of the
National Academy of Sciences, USA, visit:
[www.pnas.org]

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