title: A turanose-insensitive mutant suggests a role for WOX5 in auxin homeostasis in Arabidopsis thaliana.
abstract: Sugars acting as signalling molecules regulate many developmental processes in plants, including lateral and adventitious root production. Turanose, a non-metabolizable sucrose analogue, profoundly affects the growth pattern of Arabidopsis seedlings. Turanose-treated seedlings are characterized by a very short primary root and a short hypocotyl showing the production of adventitious roots. A turanose-insensitive (tin) mutant was identified and characterized. Because of a T-DNA insertion and a chromosomal translocation, tin expresses a chimeric form of WOX5, a gene known to be expressed in the root quiescent centre. The tin mutation can be complemented by overexpression of WOX5, suggesting it is a loss-of-function mutant. We found that WOX5 is both turanose- and auxin-inducible. Moreover, turanose insensitivity is associated with altered auxin homeostasis, as demonstrated by the constitutive activation of indole acetic acid (IAA) conjugation and SUPERROOT2 expression in tin. On the basis of turanose effects on wild-type seedlings and the tin molecular and hormonal phenotype, we propose a role for WOX5 in the root apical meristem as a negative trigger of IAA homeostatic mechanisms allowing the maintenance of a restricted area of auxin maximum, which is required for a correct root-formation pattern.
authors.affiliation: Department of Crop Plant Biology, University of Pisa, Via Mariscoglio 34, Pisa, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gonzali
authors.forename: Giacomo
authors.initials: G
authors.lastname: Novi
authors.forename: Elena
authors.initials: E
authors.lastname: Loreti
authors.forename: Fabio
authors.initials: F
authors.lastname: Paolicchi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Poggi
authors.forename: Amedeo
authors.initials: A
authors.lastname: Alpi
authors.forename: Pierdomenico
authors.initials: P
authors.lastname: Perata
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004187:Disaccharides / Q000494:pharmacology*; D004351:Drug Resistance / Q000235:genetics; D005030:Ethylenes / Q000378:metabolism; D015870:Gene Expression; D017343:Genes, Plant; D005816:Genetic Complementation Test; D006706:Homeostasis; D007210:Indoleacetic Acids / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D009154:Mutation; D030821:Plants, Genetically Modified; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014178:Translocation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D004187:Disaccharides; D005030:Ethylenes; D007210:Indoleacetic Acids; C036483:T-DNA; D014157:Transcription Factors; C029454:turanose; C036216:ethylene