Fruit quality and DNA methylation are affected by parental order in reciprocal crosses of tomato

Abstract

Crosses between different genotypes and even between different species arecommonly used in plant breeding programs. Reciprocal hybrids are obtained bychanging the cross direction (or the sexual role) of parental genotypes in a cross.Phenotypic differences between these hybrids constitute reciprocal effects (REs). Theaim of this study was to evaluate phenotypic differences in tomato fruit traits and DNAmethylation profiles in three inter- and intraspecific reciprocal crosses. REs weredetected for 13 of the 16 fruit traits analyzed. The number of traits with REs was thelowest in the interspecific cross whereas the highest was found in the cross betweenRecombinant Inbred Lines (RILs) derived from the same interspecific cross. Anextension of gene action analysis was proposed in order to incorporate parent-of-origineffects (POEs). Maternal and paternal dominance were found in four fruit traits. REsand paternal inheritance were found for epiloci located at coding and non-codingregions. The epigenetic identity displayed by the reciprocal hybrids accounts for thephenotypic differences among them, indicating that DNA methylation might be one ofthe mechanisms involved in POEs.