A novel aux/IAA28 signaling cascade activates GATA23-dependent specification of lateral root founder cell identity.
BACKGROUND
Lateral roots are formed at regular intervals along the main root by recurrent specification of founder cells. To date, the mechanism by which branching of the root system is controlled and founder cells become specified remains unknown.


RESULTS
Our study reports the identification of the auxin regulatory components and their target gene, GATA23, which control lateral root founder cell specification. Initially, a meta-analysis of lateral root-related transcriptomic data identified the GATA23 transcription factor. GATA23 is expressed specifically in xylem pole pericycle cells before the first asymmetric division and is correlated with oscillating auxin signaling maxima in the basal meristem. Also, functional studies revealed that GATA23 controls lateral root founder cell identity. Finally, we show that an Aux/IAA28-dependent auxin signaling mechanism in the basal meristem controls GATA23 expression.


CONCLUSIONS
We have identified the first molecular components that control lateral root founder cell identity in the Arabidopsis root. These include an IAA28-dependent auxin signaling module in the basal meristem region that regulates GATA23 expression and thereby lateral root founder cell specification and root branching patterns.
De Rybel
Bert
B
Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Ghent, Belgium.
Vassileva
Valya
V
Parizot
Boris
B
Demeulenaere
Marlies
M
Grunewald
Wim
W
Audenaert
Dominique
D
Van Campenhout
Jelle
J
Overvoorde
Paul
P
Jansen
Leentje
L
Vanneste
Steffen
S
Möller
Barbara
B
Wilson
Michael
M
Holman
Tara
T
Van Isterdael
Gert
G
Brunoud
Géraldine
G
Vuylsteke
Marnik
M
Vernoux
Teva
T
De Veylder
Lieven
L
Inzé
Dirk
D
Weijers
Dolf
D
Bennett
Malcolm J
MJ
Beeckman
Tom
T
D050980:GATA Transcription Factors / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D063245:Plant Development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development*; D010944:Plants / Q000033:anatomy & histology / Q000235:genetics; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D050980:GATA Transcription Factors; D007210:Indoleacetic Acids; D010940:Plant Proteins