Ideal Plant Architecture 1 (IPA1) is a key regulator of plant architecture. However, knowledge of downstream genes applicable for improving rice plant architecture is very limited. We identified the plant architecture regulatory gene NARROW LEAF 11 (NAL11), which encodes a heat-shock protein (HSP) containing a DnaJ domain. A promising rare allele of NAL11 (NAL11-923del-1552 ) positively selected in Aus cultivars was identified; this allele exhibited increased expression and generated relatively few tillers, thick stems, and large panicles, components of the ideal plant architecture (IPA). NAL11 is involved in regulating the cell cycle and cell proliferation. NAL11 loss-of-function mutants present impaired chloroplast development and gibberellin (GA) defects. Biochemical analyses show that IPA1 directly binds to elements in the missing fragment of the NAL11-923del-1552 promoter and negatively regulates NAL11 expression. Genetic analyses support the hypothesis that NAL11 acts downstream of IPA1 to regulate IPA by modulating GA homeostasis, and NAL11 may be an essential complement for IPA1. Our work revealed that avoidance of the inhibition of NAL11-923del-1552 caused by IPA1 represents a positive strategy for rescuing GA defects accompanied by the upregulation of IPA1 in breeding high-yield rice.

中文翻译：

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含有 DnaJ 结构域的热休克蛋白 NAL11 通过介导水稻 (Oryza sativa) 中的赤霉素稳态来决定植物结构。

Ideal Plant Architecture 1 (IPA1) 是植物结构的关键调节剂。然而，适用于改善水稻植株结构的下游基因的知识非常有限。我们鉴定了植物结构调控基因 NARROW LEAF 11 (NAL11)，它编码含有 DnaJ 结构域的热休克蛋白 (HSP)。鉴定了在澳大利亚栽培品种中积极选择的 NAL11 (NAL11-923del-1552) 的一个有前途的稀有等位基因；该等位基因表现出增加的表达并产生相对较少的分蘖、粗茎和大圆锥花序，这些是理想植物结构 (IPA) 的组成部分。NAL11 参与调节细胞周期和细胞增殖。NAL11 功能丧失突变体存在叶绿体发育受损和赤霉素 (GA) 缺陷。生化分析表明，IPA1 直接与 NAL11-923del-1552 启动子缺失片段中的元素结合，负向调节 NAL11 的表达。遗传分析支持 NAL11 作用于 IPA1 下游以通过调节 GA 稳态来调节 IPA 的假设，并且 NAL11 可能是 IPA1 的重要补充。我们的工作表明，避免由 IPA1 引起的 NAL11-923del-1552 抑制代表了在育种高产水稻中挽救伴随 IPA1 上调的 GA 缺陷的积极策略。