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Nature Plants：拟南芥根组织维管形成层的转录调控网络

已有 4563 次阅读 2019-10-11 19:00 |个人分类:每日摘要|系统分类:论文交流|文章来源:转载

Transcriptional regulatory framework for vascular cambium development in Arabidopsis roots

First author: Jing Zhang; Affiliations: University of Helsinki (赫尔辛基大学): Helsinki, Finland

Corresponding author: Ykä Helariutta

Vascular cambium, a lateral plant meristem, is a central producer of woody biomass. Although a few transcription factors have been shown to regulate cambial activity, the phenotypes of the corresponding loss-of-function mutants are relatively modest, highlighting our limited understanding of the underlying transcriptional regulation. Here, we use cambium cell-specific transcript profiling followed by a combination of transcription factor network and genetic analyses to identify 62 new transcription factor genotypes displaying an array of cambial phenotypes. This approach culminated in virtual loss of cambial activity when both WUSCHEL-RELATED HOMEOBOX 4 (WOX4) and KNOTTED-like from Arabidopsis thaliana 1 (KNAT1; also known as BREVIPEDICELLUS) were mutated, thereby unlocking the genetic redundancy in the regulation of cambium development. We also identified transcription factors with dual functions in cambial cell proliferation and xylem differentiation, including WOX4, SHORT VEGETATIVE PHASE (SVP) and PETAL LOSS (PTL). Using the transcription factor network information, we combined overexpression of the cambial activator WOX4 and removal of the putative inhibitor PTL to engineer Arabidopsis for enhanced radial growth. This line also showed ectopic cambial activity, thus further highlighting the central roles of WOX4 and PTL in cambium development.

维管形成层是植物的侧生分生组织，对于木材生物量的生产至关重要。尽管已知有一些转录因子参与形成层活性的调控，但相应的功能缺失突变体的表型相对来说不太严重，所以对于形成层活性的转录调控机制还有待深入研究。本文中，作者利用形成层细胞特异性转录谱结合转录因子网络和遗传学分析鉴定了62个新的转录因子会影响形成层的活性。当拟南芥的WOX4和KNAT1基因同时被突变会导致形成层活性的完全丧失，从而揭示了形成层发育遗传调控的冗余性。作者还鉴定了一些转录因子在形成层细胞增殖和木质部分化中存在双重作用，包括WOX4、SVP以及PLT。利用转录因子网络的信息，作者结合了形成层激活因子WOX4基因的过表达和潜在的抑制因子PTL基因的敲除，成功增加了拟南芥的径向生长。该株系还显示出异位的形成层活性，进一步说明了WOX4和PTL基因在形成层发育过程中具有关键作用。