Reciprocal interploidy hybrid seed RNA-seq in Arabidopsis arenosa: maternal- vs paternal-excess triploid block
Polyploidy can generate new plant lineages, but crosses between diploids and tetraploids often fail due to the triploid block. This study provides RNA-seq of young seeds from reciprocal interploidy crosses between natural diploid and autotetraploid populations of Arabidopsis arenosa from two independent ploidy contact zones. By comparing maternal-excess (4x x 2x) and paternal-excess (2x x 4x) hybrids, we identify gene misexpression and pathway dysregulation linked to hybrid seed failure, including parent-of-origin effects in imprinted genes and tissue-associated responses across embryo, endosperm, and seed coat. These data are relevant for understanding how post-zygotic barriers maintain ploidy boundaries and shape polyploid speciation in natural systems, and for cross-species comparisons of conserved triploid-block signatures.