ABSTRACT
Human activities have greatly accelerated the rates of global environmental change (Vitousek et al. 1997). Understanding the consequences of these changes for forest ecosystems is one of the more pressing challenges confronting the scientific community today, given the importance of forests in global net primary production (NPP), carbon sequestration, human economies, and as repositories of biodiversity (Hassan et al. 2005). The effects of environmental change will occur fi rst and foremost in the activation or suppression of genes within the species of these systems. Altered gene expression drives plant function, and gene expression at all levels is the fi rst transponder that receives the signal that the atmosphere has changed. Any alteration of gene expression sequence that controls the allocation of photosynthate to below-ground structures also has the potential of infl uencing root function via effects on processes associated with membrane permeability and transporter function, membrane repair, and the production of signaling molecules important in regulating mycorrhizal and pathogen interactions (Garrett et al. 2006). It is important then, in order to better anticipate the consequences of environmental change, to
identify those genes that are activated by an alteration of environmental conditions. More specifi cally, it is important to be able to identify those genes or gene sequences that are good surrogates of the metabolic state of an individual but can also be used to scale from the individual to higher organization levels as a robust indicator of a change in the community or ecosystem properties.
