From genes to ecosystems: a synthesis of the effects of plant genetic factors across levels of organization

Using two geneticapproaches and seven different plant systems, we present findings from a meta-analysis examining the strength of the effects of plant genetic introgressionand genotypic diversity across individual, community and ecosystem levels with the goal of synthesizing the patterns to date. We found that (i) the strength of plant geneticeffects can be quite high; however, the overall strength of geneticeffects on most response variables declined as the levels of organization increased. (ii) Plant geneticeffects varied such that introgressionhad a greater impact on individual phenotypes than extended effects on arthropodsor microbes/fungi. By contrast, the greatest effects of genotypic diversity were on arthropods. (iii) Plant geneticeffects were greater on above-ground versus below-ground processes, but there was no difference between terrestrial and aquatic environments. (iv) The strength of the effects of intraspecific genotypic diversity tended to be weaker than interspecific genetic introgression. (v) Although geneticeffects generally decline across levels of organization, in some cases they do not, suggesting that specific organisms and/or processes may respond more than others to underlying genetic variation. Because patterns in the overall impacts of introgressionand genotypic diversity were generally consistent across diverse study systems and consistent with theoretical expectations, these results provide generality for understanding the extended consequences of plant geneticvariation across levels of organization, with evolutionary implications.