An auxin signaling gene BnaA3.IAA7 contributes to improved plant architecture and yield heterosis in rapeseed
An auxin signaling gene BnaA3.IAA7 contributes to improved plant architecture and yield heterosis in rapeseed
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生长素信号基因 BnaA3.IAA7 有助于改善油菜植物结构和产量杂种优势
DOI：
10.1111/nph.15632
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发表时间：
2019-04-01
期刊：
影响因子：
9.4
通讯作者：
Liu, Kede
中科院分区：
文献类型：
--
作者：
Li, Haitao;Li, Juanjuan;Liu, Kede
植物构型是影响许多作物总产量的关键因素。油菜（Brassica napus）是一种重要的全球油料作物，其植物结构的遗传基础是难以捉摸的。本研究对经甲基磺酸乙酯（EMS）诱变的油菜突变体sca进行了表征，发现该突变体具有多个表型改变，包括皱叶、半矮秆、窄分支角和直立角果，并鉴定了编码Aux/IAA蛋白的基因（BnaA 3. IAA 7）。G-to-A突变将第84位的甘氨酸变为谷氨酸（G84 E），破坏了保守的降解决定子基序GWPPV，并以生长素剂量依赖性方式降低了BnaA3.IAA7与TIR 1（转运抑制剂反应1）之间的亲和力。这种变化抑制了BnaA3.IAA7的降解，因此在低水平的生长素下抑制了生长素信号传导，从而减少了节间的长度。G84 E突变通过增强向重力性反应而减小了分支角度。杂合子+/sca与理想的植株结构非常相似，通过多个组成性状的改良，通过单位点超显性表现出较强的产量杂种优势。BnaA 3、IAA 7功能突变可通过改善植株构型而提高产量优势，对选育上级油菜杂交种具有重要价值这种突变可能会增加其他芸苔属作物的产量。
Plant architecture is the key factor affecting overall yield in many crops. The genetic basis underlying plant architecture in rapeseed (Brassica napus), a key global oil crop, is elusive. We characterized an ethyl methanesulfonate (EMS)-mutagenized rapeseed mutant, sca, which had multiple phenotypic alterations, including crinkled leaves, semi-dwarf stature, narrow branch angles and upward-standing siliques.We identified the underlying gene, which encodes an Aux/IAA protein (BnaA3.IAA7). A G-to-A mutation changed the glycine at the 84(th) position to glutamic acid (G84E), disrupting the conserved degron motif GWPPV and reducing the affinity between BnaA3.IAA7 and TIR1 (TRANSPORT INHIBITOR RESPONSE 1) in an auxin dosage-dependent manner. This change repressed the degradation of BnaA3.IAA7 and therefore repressed auxin signaling at low levels of auxin that reduced the length of internodes. The G84E mutation reduced branch angles by enhancing the gravitropic response.The heterozygote +/sca closely resembled a proposed ideal plant architecture, displaying strong yield heterosis through single-locus overdominance by improving multiple component traits.Our findings demonstrate that a weak gain-of-function mutation in BnaA3.IAA7 contributes to yield heterosis by improving plant architecture and would be valuable for breeding superior rapeseed hybrid cultivars and such a mutation may increase the yield in other Brassica crops.