TY - JOUR
T1 - MEDIATOR18 influences Arabidopsis root architecture, represses auxin signaling and is a critical factor for cell viability in root meristems
AU - Raya-González, Javier
AU - Oropeza-Aburto, Araceli
AU - López-Bucio, Jesús S.
AU - Guevara-García, Ángel A.
AU - de Veylder, Lieven
AU - López-Bucio, José
AU - Herrera-Estrella, Luis
N1 - Publisher Copyright:
© 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd
PY - 2018/12
Y1 - 2018/12
N2 - 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 MEDIATOR18 (MED18) subunit in root development, auxin signaling and meristem cell viability in Arabidopsis thaliana seedlings. Loss-of-function mutations in MED18 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 DR5:GFP, pPIN1::PIN1-GFP, pPIN2::PIN2-GFP and pPIN3::PIN3-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 ERF115. 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 MED18 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 MED18 as an important component for auxin-regulated root development, cell death and cell regeneration in root meristems.
AB - 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 MEDIATOR18 (MED18) subunit in root development, auxin signaling and meristem cell viability in Arabidopsis thaliana seedlings. Loss-of-function mutations in MED18 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 DR5:GFP, pPIN1::PIN1-GFP, pPIN2::PIN2-GFP and pPIN3::PIN3-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 ERF115. 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 MED18 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 MED18 as an important component for auxin-regulated root development, cell death and cell regeneration in root meristems.
KW - Arabidopsis thaliana
KW - auxin signaling
KW - cell death
KW - regeneration
KW - root development
UR - http://www.scopus.com/inward/record.url?scp=85057090640&partnerID=8YFLogxK
U2 - 10.1111/tpj.14114
DO - 10.1111/tpj.14114
M3 - Article
C2 - 30270572
AN - SCOPUS:85057090640
SN - 0960-7412
VL - 96
SP - 895
EP - 909
JO - Plant Journal
JF - Plant Journal
IS - 5
ER -