Intraspecific comparative analyses of metabolites between diploid and tetraploid Arabidopsis thaliana and Pyrus communis

Abstract

It has been said that naturally occurring autopolyploid strains are more tolerant of biotic and/or abiotic stresses, due at least in part to the higher accumulation of secondary metabolites. Data supporting this hypothesis come from comparisons between naturally established autopolyploids and diploids; thus the high accumulation of metabolites in polyploid strains may be a secondarily acquired feature and not a direct effect of the autopolyploidy. But no detailed studies on this issue have been carried out. Here we carried out metabolome analyses between newly created tetraploids and the parent diploid in a model plant, Arabidopsis thaliana, and the agriculturally important pear fruit tree (Pyrus communis var. sativa). Our data showed that small numbers of metabolite species differ in amount between diploids and tetraploids in both species, but the differences were not reproducible among growth conditions and species. These results strongly indicate that metabolite content is not universal nor the direct target of polyploidy-dependent changes. Instead, naturally occurring hyperaccumulation of metabolites in autopolyploids may be the result of secondary natural selection.