Differential DNA methylation and gene expression during development of reproductive and vegetative organs in Ilex species

JIMENA CASCALES; RAÚL MAXIMILIANO ACEVEDO; DANIELA IVANA PAIVA; ALEXANDRA MARINA GOTTLIEB

JOURNAL OF PLANT RESEARCH

SPRINGER TOKYO

Lugar: Tokyo; Año: 2021

0918-9440

Differential epigenetic (DNA cytosine methylation) and gene expression patterns wereinvestigated in reproductive and vegetative organs from Ilex paraguariensis and I. dumosa, atdistinct developmental stages. We aimed at contributing towards elucidating major molecularchanges underlying the sexual differentiation processes which, in these dioecious species, arecompletely unknown. Simultaneously, as a first step towards the development of an early sexingsystem, we searched for promising molecular markers. This was assessed through MethylationSensitive Amplified Polymorphism (MSAP) and Amplified Fragment Length Polymorphism oncDNA (cDNA-AFLP) techniques, applying discriminant multivariate analyses, and bioinformaticcharacterization of differential fragments. A significant positive correlation was found betweenepigenetic and indirect ?genetic? information for both species, indicating influence of the geneticbackground on the epigenetic variation. Higher epigenetic than genetic diversities were estimated.Our outcomes showed up to 1.86 times more representation of mCG subepiloci than mCCG in allorgans sampled. Along the maturing stages of floral buds, the frequency of mCG evidenced anincremental trend, whereas mCCG and unmethylated conditions showed opposite tendencies.Reproductive and vegetative samples tended to cluster apart based on epigenetic patterns; at geneexpression level, organs exhibited clear-cut distinctive patterns, nonetheless profiles of youngleaves and floral primordia resemble. Epigenetic and expression data allowed discrimination of I.dumosa´s samples according to the gender of the donor; more elusive patterns were observed forI. paraguariensis. In total, 102 differentially methylated and expressed fragments werecharacterized bioinformatically. Forty-three were annotated in various functional categories; fourcandidate markers were validated through qPCR, finding statistical differences among organs butnot among sexes. The methylation condition of epilocus C13m33 appears as indicative of genderin both species. Thirty-three organ-specific and 34 gender-specific methylated markers werediscriminated and deserve further research, particularly those expressed in leaves. Our studycontributes concrete candidate markers with potential for practical application.