Molecular mechanisms underlying cork barrier differentiation: the role of MYBs transcription factors

就像我们的皮肤一样，植物身体的最外层组织，进化来保护植物免受生物和非生物物质的侵害，并控制水和气体交换的损失。周皮是在二次生长过程中覆盖和保护脉管系统的外层组织。它起源于软木形成层，它分裂并向内产生木栓层和向外产生软木。周皮的屏障特性是由软木赋予的，软木在细胞壁中积累了大量的木质素和木质素。尽管软木在经济和农学上具有重要意义，但人们对周皮形成和软木分化的调节作用知之甚少。基于几个物种的周皮/软木的转录谱分析，我们发现了一组密切相关的MYB转录因子（TFs），这些转录因子在物种中是保守的，并且在周皮/软木中特异性表达。我们利用拟南芥根作为模型的初步结果表明，这些myb在软木分化中具有双重功能。一方面促进木栓素的积累，另一方面抑制木栓形成层的活性。在这里，利用工具和资源，可以在精确定义的时空背景下诱导周皮中的tf表达，我们的目标是进一步剖析它们在软木分化过程中的作用，确定它们的目标，从而建立第一个软木调控网络。此外，我们将重点研究它们在非生物胁迫下的功能，为针对根屏障的育种计划铺平道路。

Like our skin, the outermost tissues of the plant body, evolved to protect the plant against biotic and abiotic agents and to control loss of water and gas exchanges. The periderm, is the outer tissue that covers and protects the vasculature during secondary growth. It originates from the cork cambium, which divides and produces inward the phelloderm and outward the cork. The barrier properties of the periderm are conferred by the cork, which accumulates high amount of suberin and lignin in the cell walls. Despite the economic and agronomical importance of the cork, few regulators of periderm formation and cork differentiation are known. Based on periderm/cork transcript-profiling of several species, we identified a set of closely related MYB transcription factors (TFs), which are conserved among species and specifically expressed in the periderm/cork. Our preliminary results, exploiting the Arabidopsis root, as a model, suggest a dual function in cork differentiation for these MYBs. On one hand, they promote suberin accumulation and on the other hand they repress cork cambium activity. Here, exploiting tools and resources in which TFs expression in the periderm can be induced in a precisely defined spatiotemporal context, we aim to further dissect their role during cork differentiation, to identify their targets and thus establish the first cork regulatory network. In addition, we will focus on their function during abiotic stresses, paving the way for breeding programs targeting root barriers.