The Genetic Basis of Overcompensation in Plants: A Synthesis

Although genetic variation for co mpensation exists, studies of the mechanisms underlying such variation have only recently been reported. Here we synthesize, and add new information, on what is known to date about the genetic underpinnings of plant compensation following insect and mammalian herb ivory with a focus predominantly on the phenomenon of overcompensation. These studies have centered on the role of endoreduplication in co mpensation and genes involved in the compensatory response. Specifically, we p ropose that plants with the capability of overco mpensating (increasing both biomass and fitness when compared to undamaged controls) reprogram their transcriptional act ivity in at least three important ways: 1) through a suite of defensive mechanisms, 2) through an increase in expression of genes involved in energy metabolism and 3) through an increase in DNA content (via endoreduplication), with the increase in DNA content feeding back on pathways involved in defense and metabolism through increased gene expression.