Table_7_Parent-of-Origin Effects on Seed Size Modify Heterosis Responses in Arabidopsis thaliana.DOCX

Parent-of-origin effects arise when a phenotype depends on whether it is inherited maternally or paternally. Parent-of-origin effects can exert a strong influence on F1 seed size in flowering plants, an important agronomic and life-history trait that can contribute to biomass heterosis. Here we investigate the natural variation in the relative contributions of the maternal and paternal genomes to F1 seed size across 71 reciprocal pairs of F1 hybrid diploids and the parental effect on F1 seed size heterosis. We demonstrate that the paternally derived genome influences F1 seed size more significantly than previously appreciated. We further demonstrate (by disruption of parental genome dosage balance in F1 triploid seeds) that hybridity acts as an enhancer of genome dosage effects on F1 seed size, beyond that observed from hybridity or genome dosage effects on their own. Our findings indicate that interactions between genetic hybridity and parental genome dosage can enhance heterosis effects in plants, opening new avenues for boosting heterosis breeding in crop plants.

亲本来源效应（Parent-of-origin effects）指表型取决于其遗传自母本还是父本的现象。亲本来源效应对开花植物的F1种子大小具有显著影响，而F1种子大小是一类重要的农艺与生活史性状，可参与调控生物量杂种优势。本研究针对71对正反交F1杂交二倍体，探究了母本与父本基因组对F1种子大小的相对贡献的自然变异，以及亲本效应对F1种子大小杂种优势的影响。研究证实，父本来源基因组对F1种子大小的影响程度远超此前认知。进一步通过破坏F1三倍体种子的亲本基因组剂量平衡，我们发现：杂交性可增强基因组剂量对F1种子大小的调控效应，这一效果优于单独通过杂交性或基因组剂量所产生的效应。本研究结果表明，遗传杂交性与亲本基因组剂量之间的互作可强化植物的杂种优势效应，为作物杂种优势育种开辟了全新路径。