Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.
Waksman Institute, Rutgers University, Piscataway, NJ, 08854, USA.
Nat Commun. 2022 Sep 13;13(1):5366. doi: 10.1038/s41467-022-33055-9.
Historically, xenia effects were hypothesized to be unique genetic contributions of pollen to seed phenotype, but most examples represent standard complementation of Mendelian traits. We identified the imprinted dosage-effect defective1 (ded1) locus in maize (Zea mays) as a paternal regulator of seed size and development. Hypomorphic alleles show a 5-10% seed weight reduction when ded1 is transmitted through the male, while homozygous mutants are defective with a 70-90% seed weight reduction. Ded1 encodes an R2R3-MYB transcription factor expressed specifically during early endosperm development with paternal allele bias. DED1 directly activates early endosperm genes and endosperm adjacent to scutellum cell layer genes, while directly repressing late grain-fill genes. These results demonstrate xenia as originally defined: Imprinting of Ded1 causes the paternal allele to set the pace of endosperm development thereby influencing grain set and size.
从历史上看，异种效应被假设为花粉对种子表型的独特遗传贡献，但大多数例子代表了孟德尔性状的标准互补。我们在玉米（Zea mays）中鉴定了印迹剂量效应缺陷 1（ded1）基因座，它是调节种子大小和发育的父本调控因子。当 ded1 通过雄性传递时，弱等位基因表现出 5-10%的种子重量减少，而纯合突变体则缺陷，种子重量减少 70-90%。ded1 编码一个 R2R3-MYB 转录因子，在早期胚乳发育过程中特异性表达，具有父本等位基因偏倚。DED1 直接激活早期胚乳基因和靠近盾片细胞层的胚乳基因，同时直接抑制晚期灌浆基因。这些结果证明了异种效应的最初定义：Ded1 的印迹导致父本等位基因设定胚乳发育的速度，从而影响谷物的形成和大小。
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