title: Strigolactone signaling in the endodermis is sufficient to restore root responses and involves SHORT HYPOCOTYL 2 (SHY2) activity.
abstract: Strigolactones (SLs) are plant hormones and regulators of root development, including lateral root (LR) formation, root hair (RH) elongation and meristem cell number, in a MORE AXILLARY GROWTH 2 (MAX2)-dependent way. However, whether SL signaling is acting cell-autonomously or in a non-cell-autonomous way in roots is unclear. We analyzed root phenotype, hormonal responses and gene expression in multiple lines of Arabidopsis thaliana max2-1 mutants expressing MAX2 under various tissue-specific promoters and shy2 mutants. The results demonstrate for the first time that expression of MAX2 under the SCARECROW (SCR) promoter, expressed mainly in the root endodermis, is sufficient to confer SL sensitivity in the root for RH, LR and meristem cell number. Moreover, loss of function mutation of SHORT HYPOCOTYL 2 (SHY2), a key component in auxin and cytokinin regulation of meristem size, has been found to be insensitive to SLs in relation to LR formation and meristem cell number. Endodermal SL signaling, mediated by MAX2, is sufficient to confer SL sensitivity in root, and SHY2 may participate in SL signaling to regulate meristem size and LR formation. These SL signaling pathways thus may act through modulation of auxin flux in the root tip, and may indicate a root-specific, yet non-cell-autonomous regulatory mode of action.
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Dikla
authors: D
authors: Koren
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Nathalie
authors: N
authors: Resnick
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Einav Mayzlish
authors: EM
authors: Gati
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Eduard
authors: E
authors: Belausov
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Smadar
authors: S
authors: Weininger
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Yoram
authors: Y
authors: Kapulnik
authors: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, PO Box 6, Bet Dagan, 50250, Israel.
authors: Hinanit
authors: H
authors: Koltai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D007783:Lactones / Q000378:metabolism / Q000494:pharmacology; D018519:Meristem / Q000166:cytology / Q000235:genetics; D009154:Mutation; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D003583:Cytokinins; C507382:GR24 compound; D007783:Lactones; C435920:MAX2 protein, Arabidopsis; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; C100978:SCR protein, Arabidopsis; C117994:SHY2 protein, Arabidopsis