Specification and regulation of vascular tissue identity in the Arabidopsis embryo

First author: Margot E. Smit; Affiliations: Wageningen University (瓦赫宁根大学): Wageningen, the Netherlands

Corresponding author: Dolf Weijers

Development of plant vascular tissues involves tissue identity specification, growth, pattern formation and cell type differentiation. While later steps are understood in some detail, it is still largely unknown how the tissue is initially specified. We have used the early Arabidopsis embryo as a simple model to study this process. Using a large collection of marker genes, we find that vascular identity is specified in the 16-cell embryo. After a transient precursor state however, there is no persistent uniform tissue identity. Auxin is intimately connected to vascular tissue development. We find that while AUXIN RESPONSE FACTOR5/MONOPTEROS/ (ARF5/MP)-dependent auxin response is required, it is not sufficient for tissue specification. We therefore used a large-scale enhanced Yeast One Hybrid assay to identify potential regulators of vascular identity. Network and functional analysis of suggest that vascular identity is under robust, complex control. We found that one candidate regulator, the G-class bZIP transcription factor GBF2, can modulate vascular gene expression by tuning MP output through direct interaction. Our work uncovers components of a gene regulatory network that controls the initial specification of vascular tissue identity.

植物维管组织的发育涉及到组织特性（tissue identity）特化（specification）、生长、模式形成（pattern formation）以及细胞类型（cell type）分化（differentiation）。目前，我们对于后续的进程已经有了大致的了解，但对于最初组织是如何特化的还不清楚。本文中，作者利用早期的拟南芥胚胎作为研究模型，来探索最初的组织特化过程。利用大量的标记基因，作者发现拟南芥胚胎发生早期的组织特化发生在16细胞期。经过一个短暂的前体状态，并没有长期存在的、统一的组织特性。维管组织的发育与生长素密切相关。作者发现生长素相应因子ARF5/MP依赖型的生长素响应是拟南芥胚胎发育早期组织特化的必要条件，但并不是组织特化的充分条件。因此，作者通过大规模的改良酵母单杂实验鉴定了维管特性的潜在调控因子。网络和功能分析显示维管特性受到了非常稳健且复杂的控制。作者发现一个潜在的调控因子，G类bZIP转录因子GBF2可以通过直接的互作调控MP的输出，从而调节维管基因的表达。本文的工作揭示了控制拟南芥胚胎发生早期维管组织特性最初特化的基因调控网络的组分。

通讯：Dolf Weijers (https://f1000.com/prime/thefaculty/member/1058938112246895)

个人简介：1997年，荷兰恩斯赫德，生物化学学士；2002年，荷兰莱顿大学，发育遗传学博士；2002-2006年，德国图宾根大学，Gerd Jürgens实验室博士后。

研究方向：以拟南芥早期胚胎为材料研究细胞如何获取其特性。

doi: 10.1242/dev.186130

Journal: Development

Published date: March 20, 2020

p.s. 通讯往期文章链接：

实验室介绍：Dolf Weijers Lab (荷兰瓦赫宁根大学)

Cell：动、植物细胞极性的共同起源

Developmental Cell：植物胚胎发生综述

Nature Plants：SOSEKI蛋白影响拟南芥植株整体极性

Plant Cell：bHLH转录因子调控网络介导拟南芥胚和胚柄发育

eLife：核生长素响应系统的起源与演化

Nature Plants：拟南芥早期胚胎动态转录组研究