title: Strigolactones are positive regulators of light-harvesting genes in tomato.
abstract: Strigolactones are newly identified plant hormones, shown to participate in the regulation of lateral shoot branching and root development. However, little is known about their effects on biological processes, genes, and proteins. Transcription profiling of roots treated with GR24, a synthetic strigolactone with proven biological activity, and/or indole acetic acid (IAA) was combined with physiological and transcriptional analysis of a tomato mutant (Sl-ORT1) deficient in strigolactone production. GR24 treatment led to markedly induced expression of genes putatively involved in light harvesting. This was apparent in both the presence and absence of exogenously applied IAA, but not with IAA treatment alone. Following validation of the microarray results, transcriptional induction by light of the GR24-induced genes was demonstrated in leaves exposed to high or low light intensities. Sl-ORT1 contained less chlorophyll and showed reduced expression of light harvesting-associated genes than the wild type (WT). Moreover, perfusion of GR24 into WT and Sl-ORT1 leaves led to induction of most of the examined light harvesting-associated genes. Results suggest that GR24 treatment interferes with the root's response to IAA treatment and that strigolactones are potentially positive regulators of light harvesting in plants.
authors.affiliation: Institute of Plant Sciences, Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, Israel.
authors.forename: Einav
authors.initials: E
authors.lastname: Mayzlish-Gati
authors.forename: Sivarama P
authors.initials: SP
authors.lastname: LekKala
authors.forename: Nathalie
authors.initials: N
authors.lastname: Resnick
authors.forename: Smadar
authors.initials: S
authors.lastname: Wininger
authors.forename: Chaitali
authors.initials: C
authors.lastname: Bhattacharya
authors.forename: J Hugo
authors.initials: JH
authors.lastname: Lemcoff
authors.forename: Yoram
authors.initials: Y
authors.lastname: Kapulnik
authors.forename: Hinanit
authors.initials: H
authors.lastname: Koltai
mesh_terms: D002338:Carotenoids / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000235:genetics* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D002338:Carotenoids