biostudies-literatureWang ZUSDA8310https://www.ebi.ac.uk/biostudies/studies/S-EPMC12428041biostudies-literatureUnknown26(17)Seed size is a key trait affecting evolution and agronomic performance by influencing seedling establishment in natural populations and crop yields. The <i>Arabidopsis thaliana</i> Seed Size QTL1 (SSQ1) locus explains 10-15% of the variation in seed size. We report here that the causal gene for this locus is <i>Tetratricopeptide Repeat Protein 2</i> (<i>TPR2</i>), which encodes a co-chaperone. Expressing <i>TPR2</i> across ecotypes and genotypes showed consistent dosage effects. Each additional <i>TPR2</i><sup>Col-0</sup> allele increased seed mass and volume by 10-14% with high reliability in Col-0, Sha, Tsu-1, and <i>tsu2</i> genetic backgrounds. Reciprocal genetic crosses indicated that this locus acts maternally, consistent with female sporophytic or female gametophytic mutations. To eInternational journal of molecular sciences<i>Tetratricopeptide Repeat 2</i> Is a Quantitative Trait Locus That Controls Seed Size.PMC124280412008-35100-19244Cara SHauser BARhee SYWang Zfalse<i>Tetratricopeptide Repeat 2</i> Is a Quantitative Trait Locus That Controls Seed Size.Seed size is a key trait affecting evolution and agronomic performance by influencing seedling establishment in natural populations and crop yields. The <i>Arabidopsis thaliana</i> Seed Size QTL1 (SSQ1) locus explains 10-15% of the variation in seed size. We report here that the causal gene for this locus is <i>Tetratricopeptide Repeat Protein 2</i> (<i>TPR2</i>), which encodes a co-chaperone. Expressing <i>TPR2</i> across ecotypes and genotypes showed consistent dosage effects. Each additional <i>TPR2</i><sup>Col-0</sup> allele increased seed mass and volume by 10-14% with high reliability in Col-0, Sha, Tsu-1, and <i>tsu2</i> genetic backgrounds. Reciprocal genetic crosses indicated that this locus acts maternally, consistent with female sporophytic or female gametophytic mutations. To e2025-01-01T00:00:00Z2025 Aug2026-04-08T19:32:16.489Z2026-04-08T13:55:45.734ZS-EPMC124280414094323710.3390/ijms26178310