Two MADS-box genes regulate vascular cambium activity and secondary growth via modulating auxin homeostasis in Populus

第一作者：Shuai Zheng

第一单位：中科院植物生理生态研究所

通讯作者：Laigeng Li

Abstract

背景回顾：In trees, stem secondary growth depends on vascular cambium proliferation activity and subsequent cell differentiation, in which a gradient of auxin concentration cross the cambium area plays a crucial role in regulating the process.

提出问题：However, the underlying molecular mechanism for establishment of the auxin concentration is not fully understood.

主要发现：In this study, we identified two function-unknown MADS-box genes, VCM1 and VCM2, which are expressed specifically in the vascular cambium and modulated the subcellular homeostasis of auxin.

结果1-敲低：Simultaneous knock-down of both VCM1 and VCM2 enhanced vascular cambium proliferation activity and subsequent xylem differentiation.

结果2-过表达：Overexpression of VCM1 suppressed vascular cambium activity and wood formation by regulating PIN5 expression which tuned the soluble auxin concentration in the vascular cambium area.

结论：The study uncovers the role of VCM1 and VCM2 in regulating the proliferation activity of the vascular cambium and secondary growth by modulating the subcellular auxin homeostasis in Populus.

摘要

在树木中，树干的次级生长依赖于维管形成层的增殖活性以及后续的细胞分化，而跨越形成层区域的生长素浓度梯度在其中发挥了非常重要的作用。但是，如何建立起这样的生长素浓度梯度，具体的分子调控机制还不清楚。本文中，作者鉴定到了两个功能未知的MADS-box基因，即VCM1和VCM2基因，在维管形成层中特异表达，并且调控生长素的亚细胞稳态。同时将VCM1和VCM2基因的表达量敲低会增强维管形成层的增殖活性，以及后续的木质部分化。过表达VCM1基因会通过调控PIN5的表达，调节维管形成层区域的可溶性生长素浓度，从而抑制维管形成层活性和木材形成。本文的研究揭示了杨树中，VCM1和VCM2基因通过调控亚细胞层面的生长素稳态，作用于维管形成层的增殖活性和次生生长。