INVESTIGADORES
CHAN Raquel Lia
artículos
Título:
A role for LAX2 in regulating xylem development and lateral-vein symmetry in the leaf
Autor/es:
MORENO-PIOVANO, GUILLERMO S.; MORENO, JAVIER E.; CABELLO, JULIETA V.; ARCE, AGUSTÍN L.; OTEGUI, MARÍA E.; CHAN, RAQUEL L.
Revista:
ANNALS OF BOTANY
Editorial:
OXFORD UNIV PRESS
Referencias:
Año: 2017
ISSN:
0305-7364
Resumen:
Background and Aims The symmetry of venation patterning in leaves is highly conservedwithin a plant species. Auxins are involved in this process and also in xylemvasculature development. Studying transgenic Arabidopsis plants ectopicallyexpressing the sunflower transcription factor HaHB4, we observed a significantlateral-vein asymmetry in leaves and in xylem formation compared to wild typeplants. In order to unravel the molecular mechanisms behind this phenotype,genes differentially expressed in these plants and related to auxininflux/efflux were investigated.Methods Candidate genes responsible for the observed phenotypes wereselected using a co-expression analysis.Single and multiple mutants in auxin influx/efflux carriers were characterizedby morphological, physiological and molecular techniques. The analysis was furthercomplemented by restoring the wild type phenotype by mutant complementationstudies and using transgenic soybean plants ectopically expressing HaHB4.Key Results LAX2, down-regulated in HaHB4transgenic plants, wasbioinformatically chosen as a candidate gene. The quadruple mutant aux1 lax1lax2 lax3 and the single mutants, except lax1, presented an enhanced asymmetry in the venation patterning. Additionally,the xylem vasculature of the lax2-mutantand the HaHB4-expressing plantsdiffered from the WT vasculature, including increased xylem length and numberof xylem cell rows. The complementation of lax2mutant with the LAX2 gene restoredboth lateral-vein symmetry and xylem/stem area ratio in the stem, showing thatauxin homeostasis is required to achieve normal vascular development.Interestingly, soybean plants ectopically expressing HaHB4 also showed an increased asymmetry in the venationpatterning, accompanied by the repression of several GmLAX genes.Conclusions Auxin influx carriers have asignificant role in leaf venation pattering in leaves and, in particular, LAX2is required for normal xylem development likely controlling auxin homeostasis.