title: Auxin synthesis gene tms1 driven by tuber-specific promoter alters hormonal status of transgenic potato plants and their responses to exogenous phytohormones.
abstract: Ectopic auxin overproduction in transgenic potato leads to enhanced productivity accompanied with concerted and occasional changes in hormonal status, and causing altered response of transformants to exogenous auxin or cytokinin. Previously, we generated potato transformants expressing Agrobacterium-derived auxin synthesis gene tms1 driven by tuber-specific patatin gene promoter (B33-promoter). Here, we studied the endogenous hormonal status and the response to exogenous phytohormones in tms1 transformants cultured in vitro. Adding indole-3-acetic acid (IAA) or kinetin to culture medium affected differently tuberization of tms1-transformed and control plants, depending also on sucrose content in the medium. Exogenous phytohormones ceased to stimulate the tuber initiation in transformants at high (5-8%) sucrose concentration, while in control plants the stimulation was observed in all experimental settings. Furthermore, exogenous auxin partly inhibited the tuber initiation, and exogenous cytokinin reduced the average tuber weight in most transformants at high sucrose content. The elevated auxin level in tubers of the transformants was accompanied with a decrease in content of cytokinin bases and their ribosides in tubers and most shoots. No concerted changes in contents of abscisic, jasmonic, salicylic acids and gibberellins in tubers were detected. The data on hormonal status indicated that the enhanced productivity of tms1 transformants was due to auxin and not mediated by other phytohormones. In addition, exogenous cytokinin was shown to upregulate the expression of genes encoding orthologs of auxin receptors. Overall, the results showed that tms1 expression and local increase in IAA level in transformants affect both the balance of endogenous cytokinins and the dynamics of tuberization in response to exogenous hormones (auxin, cytokinin), the latter reaction depending also on the carbohydrate supply. We introduce a basic model for the hormonal network controlling tuberization.
authors.affiliation: Laboratory of Signaling Systems, Institute of Plant Physiology RAS, Moscow, 127276, Russia.
authors.forename: Oksana O
authors.initials: OO
authors.lastname: Kolachevskaya
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, 6708 PB, Wageningen, The Netherlands.
authors.forename: Lidiya I
authors.initials: LI
authors.lastname: Sergeeva
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, 6708 PB, Wageningen, The Netherlands.
authors.forename: Kristyna
authors.initials: K
authors.lastname: Floková
authors.affiliation: Laboratory of Signaling Systems, Institute of Plant Physiology RAS, Moscow, 127276, Russia.
authors.forename: Irina A
authors.initials: IA
authors.lastname: Getman
authors.affiliation: Laboratory of Signaling Systems, Institute of Plant Physiology RAS, Moscow, 127276, Russia.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Lomin
authors.affiliation: Plant Biotechnology Laboratory, Branch of Institute of Bioorganic Chemistry RAS, Pushchino, 142290, Russia.
authors.forename: Valeriya V
authors.initials: VV
authors.lastname: Alekseeva
authors.affiliation: Plant Biotechnology Laboratory, Branch of Institute of Bioorganic Chemistry RAS, Pushchino, 142290, Russia.
authors.forename: Elena B
authors.initials: EB
authors.lastname: Rukavtsova
authors.affiliation: Plant Biotechnology Laboratory, Branch of Institute of Bioorganic Chemistry RAS, Pushchino, 142290, Russia.
authors.forename: Yaroslav I
authors.initials: YI
authors.lastname: Buryanov
authors.affiliation: Laboratory of Signaling Systems, Institute of Plant Physiology RAS, Moscow, 127276, Russia. gromanov@yahoo.com.|Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia. gromanov@yahoo.com.
authors.forename: Georgy A
authors.identifier: http://orcid.org/0000-0001-6090-6427
authors.initials: GA
authors.lastname: Romanov
mesh_terms: D018533:Biomass; D003583:Cytokinins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D007701:Kinetin / Q000494:pharmacology; D009928:Organ Specificity / Q000187:drug effects; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D035281:Plant Tubers / Q000187:drug effects / Q000235:genetics*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D011198:Solanum tuberosum / Q000187:drug effects / Q000235:genetics*; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D003583:Cytokinins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; D007701:Kinetin
keywords: Auxin; Cytokinin; Hormonal status; Phytohormones; Potato; Solanum tuberosum; Transformants; Tuberization