title: The rolB gene activates secondary metabolism in Arabidopsis calli via selective activation of genes encoding MYB and bHLH transcription factors.
abstract: It is known that the rolB gene of Agrobacterium rhizogenes increases the production of secondary metabolites in transformed plant cells, but its mechanism of action remains unclear. In this report, we demonstrate that rolB expression in Arabidopsis thaliana calli led to the activation of most genes encoding secondary metabolism-specific MYB and bHLH transcription factors (TFs), such as MYB11, MYB12, MYB28, MYB76, MYB34, MYB51, MYB122, TT2 and TT8. Accordingly, a higher transcript abundance of main biosynthetic genes related to these factors was detected. The rolB-transformed calli produced 3-fold higher levels of indolic glucosinolates (GSs) compared with normal calli but did not produce secondary metabolites from other groups. Enhanced accumulation of indolic GSs was caused by activation of MYB34, MYB51 and MYB122, and the absence of aliphatic GSs in transformed calli was caused by the inability of rolB to induce MYB29. The inability of rolB-calli to produce flavonoids was caused by the lack of MYB111 expression, induced by the rolB-mediated conversion of MYB expression from cotyledon-specific to root-specific patterns. The high specificity of rolB on secondary metabolism-specific TFs was demonstrated for the first time.
authors.affiliation: Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok 690022, Russia; Far Eastern Federal University, Vladivostok 690950, Russia. Electronic address: bulgakov@ibss.dvo.ru.
authors.forename: Victor P
authors.initials: VP
authors.lastname: Bulgakov
authors.affiliation: Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok 690022, Russia.
authors.forename: Galina N
authors.initials: GN
authors.lastname: Veremeichik
authors.affiliation: Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok 690022, Russia.
authors.forename: Valeria P
authors.initials: VP
authors.lastname: Grigorchuk
authors.affiliation: A.V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, 17 Palchevskogo Str., Vladivostok 690059, Russia.
authors.forename: Viacheslav G
authors.initials: VG
authors.lastname: Rybin
authors.affiliation: Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok 690022, Russia.
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Shkryl
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D014157:Transcription Factors; C500589:Myb protein, Arabidopsis
keywords: Arabidopsis thaliana; Flavonoids; Glucosinolates; MYB transcription factors; Plant cell culture; Regulation; rolB gene