Premium
MEDIATOR18 influences Arabidopsis root architecture, represses auxin signaling and is a critical factor for cell viability in root meristems
Author(s) -
RayaGonzález Javier,
OropezaAburto Araceli,
LópezBucio Jesús S.,
GuevaraGarcía Ángel A.,
Veylder Lieven,
LópezBucio José,
HerreraEstrella Luis
Publication year - 2018
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.14114
Subject(s) - meristem , biology , auxin , microbiology and biotechnology , arabidopsis , root hair , lateral root , arabidopsis thaliana , root cap , programmed cell death , botany , shoot , genetics , mutant , gene , apoptosis
Summary The Mediator ( MED ) complex plays a key role in the recruitment and assembly of the transcription machinery for the control of gene expression. Here, we report on the role of MEDIATOR 18 ( MED 18) subunit in root development, auxin signaling and meristem cell viability in Arabidopsis thaliana seedlings. Loss‐of‐function mutations in MED 18 reduce primary root growth, but increase lateral root formation and root hair development. This phenotype correlates with alterations in cell division and elongation likely caused by an increased auxin response and transport at the root tip, as evidenced by DR 5: GFP , pPIN 1:: PIN 1‐ GFP , pPIN 2:: PIN 2‐ GFP and pPIN 3:: PIN 3‐ GFP auxin‐related gene expression. Noteworthy, med18 seedlings manifest cell death in the root meristem, which exacerbates with age and/or exposition to DNA ‐damaging agents, and display high expression of the cell regeneration factor ERF 115 . Cell death in the root tip was reduced in med18 seedlings grown in darkness, but remained when only the shoot was exposed to light, suggesting that MED 18 acts to protect root meristem cells from local cell death, and/or in response to root‐acting signal(s) emitted by the shoot in response to light stimuli. These data point to MED 18 as an important component for auxin‐regulated root development, cell death and cell regeneration in root meristems.