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Incipient stem cell niche conversion in tissue culture: using a systems approach to probe early events in WUSCHEL ‐dependent conversion of lateral root primordia into shoot meristems
Author(s) -
Chatfield Steven P.,
Capron Resmi,
Severino Andre,
Penttila PierAndree,
Alfred Simon,
Nahal Hardeep,
Provart Nicholas J.
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12085
Subject(s) - meristem , biology , cytokinin , primordium , microbiology and biotechnology , reporter gene , shoot , gene , gene expression , auxin , botany , genetics
Summary Adventitious shoot organogenesis contributes to the fitness of diverse plant species, and control of this process is a vital step in plant transformation and in vitro propagation. New shoot meristems ( SM s) can be induced by the conversion of lateral root primorida/meristems ( LRP / LRM s) or callus expressing markers for this identity. To study this important and fascinating process we developed a high‐throughput methodology for the synchronous initiation of LRP by auxin, and subsequent cytokinin‐induced conversion of these LRP to SM s. Cytokinin treatment induces the expression of the shoot meristematic gene WUSCHEL ( WUS ) in converting LRP ( cLRP ) within 24–30 h, and WUS is required for LRP → SM conversion. Subsequently, a transcriptional reporter for CLAVATA3 ( CLV3 ) appeared 32–48 h after transfer to cytokinin, marking presumptive shoot stem cells at the apex of cLRP . Thus the spatial expression of these two components ( WUS and CLV3 ) of a regulatory network maintaining SM stem cells already resembles that seen in a vegetative shoot apical meristem ( SAM ), suggesting the very rapid initiation and establishment of the new SM s. Our high‐throughput methodology enabled us to successfully apply a systems approach to the study of plant regeneration. Herein we characterize transcriptional reporter expression and global gene expression changes during LRP → SM conversion, elaborate the role of WUS and WUS ‐responsive genes in the conversion process, identify and test putative functional targets, perform a comparative analysis of domain‐specific expression in cLRP and SM tissue, and develop a bioinformatic tool for examining gene expression in diverse regeneration systems.