Epistatic interactions mediated by DNA methylation control tocochromanol metabolism in tomato plants

PERALTA IRIS; DE LUCA, BELEN; CARRARI, FERNANDO; BERMUDEZ LUISA; BURGOS, ESTANISLAO; ASIS, RAMÓN; QUADRANA, LEANDRO

Simposio; 40th New Phytologist Symposium; 2017

Plants are sessile organisms that had developed a plethora of response mechanisms to environmental constrains. Tocochromanol biosynthesis is triggered to cope with these conditions. Regulation of this pathway can be explained at different organization levels; from changes in leaf anatomy to epigenomics. One of the last steps in tocopherol biosynthesis is catalyzed by the 2-methyl-6-phytylquinol methyltransferase, which in tomato is encoded by two paralog genes, VTE3(1) and VTE3(2). We have pointed that differential expression of VTE3(1) underlie a major QTL for tocopherol contents in fruits. Moreover, we demonstrated that variable expression of this gene is associated with differential DNA methylation of a SINE retrotransposon inserted in the promoter region of VTE3(1). Here, using a combination of wild and domesticated alleles for both paralogs, we explored the existence of potential epistatic interaction(s) between paralogs as well as (epi)genetic X environmental (GxE). Our results show that the mRNA accumulation of the different alleles follows a coordinated fashion with the methylation levels of their promoters. Furthermore, tocopherol contents in fruits show both, epistatic as well as GxE interactions. These results contribute to understand the epistatic interactions of low heritability traits and might result in novel tools to be applied in breeding programs.