Auxin controls numerous growth processes in land plants through a gene expression system that modulates ARF transcription factor activity1-3. Gene duplications in families encoding auxin response components have generated tremendous complexity in most land plants, and neofunctionalization enabled various unique response outputs during development1,3,4. However, it is unclear what fundamental biochemical principles underlie this complex response system. By studying the minimal system in Marchantia polymorpha, we derive an intuitive and simple model where a single auxin-dependent A-ARF activates gene expression. It is antagonized by an auxin-independent B-ARF that represses common target genes. The expression patterns of both ARF proteins define developmental zones where auxin response is permitted, quantitatively tuned or prevented. This fundamental design probably represents the ancestral system and formed the basis for inflated, complex systems.

中文翻译：

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最小生长素反应系统的设计原则。

生长素通过调节 ARF 转录因子活性 1-3 的基因表达系统控制陆地植物中的许多生长过程。编码生长素反应成分的家族中的基因重复在大多数陆地植物中产生了巨大的复杂性，新功能化在发育过程中实现了各种独特的反应输出1、3、4。然而，目前尚不清楚这种复杂反应系统的基本生化原理是什么。通过研究 Marchantia polymorpha 中的最小系统，我们得出了一个直观且简单的模型，其中单个生长素依赖性 A-ARF 激活基因表达。它被抑制常见靶基因的非生长素依赖性 B-ARF 拮抗。两种 ARF 蛋白的表达模式定义了允许、定量调整或阻止生长素反应的发育区域。