Rapeseed (Brassica napus) is the second largest oilseed crop worldwide. Silique length and seed weight are positively correlated with its yield. Here, a rapeseed gene DEFECTIVE IN ANTHER DEHISCENCE 1 (DAD1; Bna.A05DAD1) was isolated, and its overexpression could significantly increase the SL and SW in Arabidopsis and rapeseed through the enlargement of the silique pericarp cells. Bna.A05DAD1 expression is observed in the seeds and anthers specifically, and its associated protein is localized to the chloroplast. Transcriptomic analysis revealed that the fatty acid biosynthesis and phytohormone response pathways were influenced with Bna.A05DAD1 overexpression. Since the FATTY ACID DESATURASE 2/6 (FAD2/6) and FAD3/7/8 genes were significantly higher than the wild type, the concentrations of linoleic acid and linolenic acid were increased in the DAD1-overexpressing rapeseed plants. Besides, overexpression of Bna.A05DAD1 suppressed the negative regulation of AUXIN RESPONSE FACTOR 18 (ARF18) through upregulation of jasmonate acid (JA) biosynthesis genes (ALLENE OXIDE CYCLASE 4, AOC4; ALLENE OXIDE SYNTHASE, Bna.A02AOS and OXOPHYTODIENOATE-REDUCTASE, Bna.C03OPR), resulting in activating of auxin response genes, leading the auxin to accumulate and the SL and SW increase. Our results suggest new views about the role Bna.A05DAD1 played in regulating fatty acid composition and increasing yield in rapeseed, as well as reveal an important mechanism of the crosstalk between the JA and auxin signaling pathways in the breeding of high-yielding rapeseed.

油菜籽（甘蓝型油菜）是全球第二大油料作物。角果长度和种子重量与其产量成正相关。在这里，分离了一个在花药开裂1中有缺陷的油菜基因（DAD1；Bna.A05DAD1），其过表达可以显着提高拟南芥中的SL和SW，并通过使果皮果皮细胞扩大来增加油菜籽。Bna.A05DAD1表达特别是在种子和花药中观察到，并且其相关蛋白位于叶绿体中。转录组学分析表明，Bna.A05DAD1过表达影响脂肪酸的生物合成和植物激素反应途径。自从脂肪酸脱氢酶2 / 6（FAD2 / 6）和FAD3 / 7 / 8基因是比野生型更高的显著，亚油酸和亚麻酸的浓度在增加DAD1 -overexpressing油菜籽植物。此外，过表达Bna.A05DAD1抑制的负调控生长素应答因子18（ARF18通过茉莉酸的上调）（JA）生物合成基因（丙二烯氧化物环化酶4，AOC4 ;丙二烯氧化物合酶，Bna.A02AOS和OXOPHYTODIENOATE还原酶，Bna.C03OPR），导致激活的生长素应答基因，导致生长素积累和SL和SW增加。我们的结果提出了关于Bna.A05DAD1在调节油菜籽中脂肪酸组成和增加产量中的作用的新观点，并揭示了JA和生长素信号传导途径之间的串扰在高产油菜籽育种中的重要机制。