Subindividual variation in plants: branch-level phenotypic and epigenetic divergence of pollen grains is correlated with the epigenetic divergence of adjacent leaves
Year: 2026
Type: preprint
Abstract: The persistence across generations of somatic epigenetic mosaicism arising within plants from random drift or localized responses to the environment is an important determinant of the potential evolutionary significance of subindividual plant variation, yet practical limitations have so far precluded its study in natural plant populations. We exemplify here an indirect approach based on testing whether branch-level somatic epigenetic mosaicism exhibited by individuals of a long-lived tree (diploid sporophytes) is consistent with the phenotypic and epigenetic mosaicism exhibited by the pollen grains (haploid gametophytes) produced by the same branches. Paired samples of leaves and pollen from five distinct branches within each of five wild-growing Pistacia terebinthus L. (Anacardiaceae) trees were characterized epigenetically using genome-wide DNA cytosine methylation level and multivariate epigenetic fingerprinting. Pollen was also characterized phenotypically by grain dimensions and shape. Individual trees were somatically heterogeneous with regard to cytosine methylation level and multivariate epigenetic fingerprints of leaf tissue. Phenotypic and epigenetic features of pollen grains differed significantly among branches of the same tree. Intraplant variation in pollen phenotype and multivariate epigenetic fingerprints were significantly related to intraplant variation in epigenetic leaf features. The consistency of subindividual somatic epigenetic heterogeneity of leaves with epigenetic and phenotypic heterogeneity of haploid gametophytes from the same branches suggests that epigenetic variants arising in somatic tissues over individual lifespans could eventually contribute to the phenotypic diversity represented in the next adult generation and become established in populations. This mechanism might contribute to enhance epigenetic and phenotypic diversity in natural plant populations. One-sentence summary Pollen grains produced by differente branches of the same tree are heterogeneous with respect to size measurements and epigenetic profiles, and such subindividual heterogeneity is correlated with subindividual variation in the epigenetic profiles of the leaves in the same branches.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7164867387