The TORNADO1 and TORNADO2 genes function in several patterning processes during early leaf development in Arabidopsis thaliana.
In multicellular organisms, patterning is a process that generates axes in the primary body plan, creates domains upon organ formation, and finally leads to differentiation into tissues and cell types. We identified the Arabidopsis thaliana TORNADO1 (TRN1) and TRN2 genes and their role in leaf patterning processes such as lamina venation, symmetry, and lateral growth. In trn mutants, the leaf venation network had a severely reduced complexity: incomplete loops, no tertiary or quaternary veins, and vascular islands. The leaf laminas were asymmetric and narrow because of a severely reduced cell number. We postulate that the imbalance between cell proliferation and cell differentiation and the altered auxin distribution in both trn mutants cause asymmetric leaf growth and aberrant venation patterning. TRN1 and TRN2 were epistatic to ASYMMETRIC LEAVES1 with respect to leaf asymmetry, consistent with their expression in the shoot apical meristem and leaf primordia. TRN1 codes for a large plant-specific protein with conserved domains also found in a variety of signaling proteins, whereas TRN2 encodes a transmembrane protein of the tetraspanin family whose phylogenetic tree is presented. Double mutant analysis showed that TRN1 and TRN2 act in the same pathway.
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, B-9052 Gent, Belgium.
Gerda
G
Cnops
Pia
P
Neyt
Jeroen
J
Raes
Marica
M
Petrarulo
Hilde
H
Nelissen
Nenad
N
Malenica
Christian
C
Luschnig
Olaf
O
Tietz
Franck
F
Ditengou
Klaus
K
Palme
Abdelkrim
A
Azmi
Els
E
Prinsen
Mieke
M
Van Lijsebettens
D017360:Arabidopsis / Q000145:classification / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics*; D017124:Conserved Sequence; D018548:Cotyledon / Q000033:anatomy & histology / Q000502:physiology; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental; D017343:Genes, Plant; D006706:Homeostasis; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development*; D016133:Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D017931:DNA Primers; D007210:Indoleacetic Acids