Lignin is a natural polymer interlaced with cellulose and hemicellulose in secondary cell walls (SCWs). Auxin acts via its signalling transduction to regulate most of plant physiological processes. Lignification responds to auxin signals likewise and affects the development of anther and secondary xylem in plants. In this review, the research advances of AUXIN RESPONSE FACTOR (ARF)-dependent signalling pathways regulating lignin formation are discussed in detail. In an effort to facilitate the understanding of several key regulators in this process, we present a regulatory framework that comprises protein–protein interactions at the top and protein–gene regulation divided into five tiers. This characterises the regulatory roles of auxin in lignin biosynthesis and links auxin signalling transduction to transcriptional cascade of lignin biosynthesis. Our works further point to several of significant problems that need to be resolved in the future to gain a better understanding of the underlying mechanisms through which auxin regulates lignin biosynthesis.

木质素是在二次细胞壁（SCW）中与纤维素和半纤维素交织的天然聚合物。生长素通过其信号转导起作用来调节大多数植物生理过程。木质化同样对生长素信号产生响应，并影响植物中花药和次生木质部的发育。本文综述了依赖AUXIN反应因子（ARF）调节木质素形成的信号通路的研究进展。为了促进对这一过程中几个关键调控因子的理解，我们提出了一个调控框架，该框架包括顶部的蛋白质-蛋白质相互作用以及分为五个层次的蛋白质-基因调控。这表征了生长素在木质素生物合成中的调节作用，并将生长素信号转导与木质素生物合成的转录级联联系起来。