Transcriptional regulatory framework for vascular cambium development in Arabidopsis roots.

Nature plants 2019 Oct

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Vascular cambium, a lateral plant meristem, is a central producer of woody biomass. Although a few transcription factors have been shown to regulate cambial activity1, 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.

Citation

Jing Zhang, Gugan Eswaran, Juan Alonso-Serra, Melis Kucukoglu, Jiale Xiang, Weibing Yang, Annakaisa Elo, Kaisa Nieminen, Teddy Damén, Je-Gun Joung, Jae-Young Yun, Jung-Hun Lee, Laura Ragni, Pierre Barbier de Reuille, Sebastian E Ahnert, Ji-Young Lee, Ari Pekka Mähönen, Ykä Helariutta. Transcriptional regulatory framework for vascular cambium development in Arabidopsis roots. Nature plants. 2019 Oct;5(10):1033-1042