Isolation of a cDNA clone for a cytokinin-repressed gene in excised cucumber cotyledons

Arabidopsis thaliana plants treated with exogenous cytokinins accumulate anthocyanin pigments. We have characterized this response because it is potentially useful as a genetic marker for cytokinin responsiveness. Levels of mRNAs for four genes of the anthocyanin biosynthesis pathway, phenylalanine ammonia lyase 1 (PAL1 ), chalcone synthase (CHS), chalcone isomerase (CHI), and dihydroflavonol reductase (DFR) were shown to increase coordinately in response to benzyladenine (BA). However, nuclear run-on transcription experiments suggested that although CHS and DFR are controlled by BA at the transcriptional level, PALl and CHI are controlled by BA posttranscriptionally. CHS mRNA levels increased within 2 h of BA spray application, and peaked by 3 h. Levels of PALl mRNA did not increase within 6 h of BA spray. We also showed that PAL1, CHS, CHI, and DFR mRNA levels fluctuate during a 24-h period and appear to be controlled by a circadian clock. The relation between cytokinin regulation and light regulation of CHS gene transcription is discussed.Cytokinins are important regulators of many aspects of plant development, including cell division, nutrient mobilization, senescence, chloroplast development, and apical dominance (Binns, 1994). Despite the widely acknowledged importance of cytokinin in plant development, very little is known about its mechanism of action at the molecular level.Cytokinins have been shown to affect the expression of specific genes by both increasing and decreasing the abundance of particular proteins or "As.A partia1 list of genes that are up-regulated by cytokinin includes nitrate reductase, rbcS, cab, hydroxypyruvate reductase in excised pumpkin cotyledons, a "multiple stimulus response" gene in Nicotiana plumbaginifolia cells, the early nodulin gene SrEnod2 from Sesbania rostrata, and a number of unidentified cDNAs from cultured soybean cells (Flores and Tobin, 1986;Chen, 1989;Crowell et al., 1990;Stabel et al., 1990;Dehio and de Bruijn, 1992;Dominov et al., 1992). Expression of phytochrome and a cucumber gene encoding a cDNA called CR9 are repressed by cytokinin (Cotton et al., 1990;Teramoto et al., 1994).

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“…Expression of phytochrome and a cucumber gene encoding a cDNA called CR9 are repressed by cytokinin (Cotton et al, 1990;Teramoto et al, 1994).…”

mentioning

confidence: 99%

Induction of Anthocyanin Accumulation by Cytokinins in Arabidopsis thaliana

Deikman¹,

Hammer²

1995

Plant Physiol.

242

154

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“…A BLAST search of the protein databases using the Os-LIR1 gene as a query showed that, in addition to the previously reported LIR1 orthologs in various vascular plant species (Reimmann and Dudler, 1993;Teramoto et al, 1994;Abied and Holland, 1994;Quigley et al, 1996;Ciannamea et al, 2007), LIR1 orthologs are also found in mosses (Sphagnum lescurii and Takakia lepidozioides), liverworts (Bazzania trilobata and Schistochila sp), and algae (Chara vulgaris and Chlorokybus atmophyticus), but none was identified in cyanobacteria (Supplemental Figure 6). The LIR1 domain (Reimmann and Dudler, 1993;Ciannamea et al, 2007), with two repeated motifs (SVFXXEACXXXGGEAC-TVFXXEACXXXGGEFC) separated by 35 to 53 amino acids, shows a high degree of conservation among the species (Supplemental Figure 7).…”

Section: The Function Of Lir1 Is Conserved In Several Dicotyledonsmentioning

confidence: 91%

“…The orthologs of LIGHT-INDUCED RICE1 (LIR1), which encodes a 13-kD protein with two almost identical repeated motifs of 16 amino acids (Supplemental Figure 1; Reimmann and Dudler, 1993;Ciannamea et al, 2007), have been identified in various angiosperm and gymnosperm species (Reimmann and Dudler, 1993;Abied and Holland, 1994;Teramoto et al, 1994;Quigley et al, 1996;Ciannamea et al, 2007). Both LIR1 motifs contain two highly conserved cysteine residues (Reimmann and Dudler, 1993;Ciannamea et al, 2007) and show a high degree of conservation among plant species, suggesting an important but yet uncharacterized functional role for the motifs.…”

Section: Introductionmentioning

confidence: 99%

“…LIR1 is expressed in a circadian manner, with transcript levels increasing during the light period, reaching a maximum at the end of the day and diminishing in the dark (Reimmann and Dudler, 1993;Hayama et al, 2002;Bläsing et al, 2005;Ciannamea et al, 2007). Moreover, LIR1 expression is induced by low temperature (Ciannamea et al, 2007) and repressed by cytokinins (Teramoto et al, 1994) and soluble sugars (Bläsing et al, 2005). Based on the diurnal rhythm of LIR1 expression and a minor delay in flowering time of Arabidopsis thaliana plants heterologously expressing ryegrass (Lolium perenne) LIR1, the LIR1 protein has been speculated to participate in the photoperiodic regulation of flowering (Hayama et al, 2002;Ciannamea et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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LIGHT-INDUCED RICE1 Regulates Light-Dependent Attachment of LEAF-TYPE FERREDOXIN-NADP⁺ OXIDOREDUCTASE to the Thylakoid Membrane in Rice and Arabidopsis

Yang

Ren

et al. 2016

Plant Cell

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LIR1 (LIGHT-INDUCED RICE1) encodes a 13-kD, chloroplast-targeted protein containing two nearly identical motifs of unknown function. LIR1 is present in the genomes of vascular plants, mosses, liverworts, and algae, but not in cyanobacteria. Using coimmunoprecipitation assays, pull-down assays, and yeast two-hybrid analyses, we showed that LIR1 interacts with LEAF-TYPE FERREDOXIN-NADP + OXIDOREDUCTASE (LFNR), an essential chloroplast enzyme functioning in the last step of photosynthetic linear electron transfer. LIR1 and LFNR formed high molecular weight thylakoid protein complexes with the TIC62 and TROL proteins, previously shown to anchor LFNR to the membrane. We further showed that LIR1 increases the affinity of LFNRs for TIC62 and that the rapid light-triggered degradation of the LIR1 coincides with the release of the LFNR from the thylakoid membrane. Loss of LIR1 resulted in a marked decrease in the accumulation of LFNR-containing thylakoid protein complexes without a concomitant decrease in total LFNR content. In rice (Oryza sativa), photosynthetic capacity of lir1 plants was slightly impaired, whereas no such effect was observed in Arabidopsis thaliana knockout mutants. The consequences of LIR1 deficiency in different species are discussed.

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“…the onset of senescence. Severa1 genes have already been shown to be down-regulated by cytokinins, but their association with a biological response controlled by cytokinins remains unclear (Crowell and Amasino, 1991;Watillon et al, 1991;Binns, 1994;Teramoto et al, 1994). It is interesting to note that SAM22, a gene induced by cytokinin starvation in soybean cells (Crowell and Amasino, 1991), was also the most expressed in senescing leaves, in addition to be developmentally and stress regulated (Crowell et al, 1992).…”

Section: P21 and P17 Are Early Markers Of A Senescence Program Triggementioning

confidence: 97%

A Thiol Protease and an Anionic Peroxidase Are Induced by Lowering Cytokinins during Callus Growth in Petunia

et al. 1996

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We previously identified a group of proteins that increase early i n Petunia hybrida calli subcultured on a low-cytokinin medium, unlike the calli subcultured on a high-cytokinin medium. The calli on the low-cytokinin medium do not regenerate (J.-P. Renaudin, C. Tournaire, B. Teyssendier de Ia Serve [1991] Physiol Plant 82: 48-56). Two of these proteins, P21 and P17, have been identified by peptide sequencing and cloned. P21 is highly homologous to a group of thiol proteases, including barley aleurain, rice oryzain y, Arabidopsis SACZ, and mammalian cathepsin H. P17 is highly homologous to a group of anionic peroxidases from potato and tomato. A study of their expression in t w o P. hybrida lines, PC6 and St40, which differ in their ability to regenerate, showed that the genes for P21 and P17 are differentially expressed depending on the type and the age of the organ, with the highest expression in senescing leaves and in aged calli. The data are in favor of these genes being associated with an early step of senescence, which may be due, i n part, to a reduction i n total cytokinin. The two fetunia lines are, thus, functionally different concerning the action of cytokinin in two developmental phenomena: in vitro organogenesis and senescence.In vitro organogenesis is a complex, developmental pathway of plant tissues under the control of a large range of effectors, including, notably, growth substances, nutrients, and light (Thorpe, 1980). The duration of the biological response, spanning days and even weeks, and the paucity of genetic studies have notably contributed to our limited understanding of the control of in vitro organogenesis. Cytokinins are considered key regulators of the formation of vegetative buds in vitro, both when they are added in vitro (Skoog and Miller, 1957) and when they are synthesized endogenously (Estruch et al., 1991; Li et al., 1992). Our knowledge of cytokinin function still lags behind that of the other plant growth substances, although some progress has been made in this area recently (Binns, 1994).We have developed a biological system to search for molecular markers of cytokinin action during in vitro organogenesis (Renaudin et al., 1990). Microcalli grown from Petunia kybrida mesophyll protoplasts were induced to regenerate * Corresponding author; e-mail renaudin@msdos.ensam.inra.fr; fax 33-67-52-57-37. buds, roots, or further calli according to the absolute concentrations of auxin and cytokinin added to the culture medium, and the effect of cytokinin on vegetative bud formation was studied (Renaudin et al., 1990;Traas et al., 1990). The continuous presence of cytokinin was required for 2 weeks, until bud primordia were formed. Vegetative buds became visible at the end of the 3rd week of culture. The growth of calli during the first 2 weeks occurred to the same extent when the cytokinin concentration was lowered 10-fold, but primordium induction and vegetative bud regeneration were triggered only by the highest cytokinin concentration.2D SDS-PAGE patterns of total protein of Petu...

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Isolation of a cDNA clone for a cytokinin-repressed gene in excised cucumber cotyledons

Cited by 19 publications

References 25 publications

Induction of Anthocyanin Accumulation by Cytokinins in Arabidopsis thaliana

Induction of Anthocyanin Accumulation by Cytokinins in Arabidopsis thaliana

LIGHT-INDUCED RICE1 Regulates Light-Dependent Attachment of LEAF-TYPE FERREDOXIN-NADP⁺ OXIDOREDUCTASE to the Thylakoid Membrane in Rice and Arabidopsis

A Thiol Protease and an Anionic Peroxidase Are Induced by Lowering Cytokinins during Callus Growth in Petunia

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Isolation of a cDNA clone for a cytokinin-repressed gene in excised cucumber cotyledons

Cited by 19 publications

References 25 publications

Induction of Anthocyanin Accumulation by Cytokinins in Arabidopsis thaliana

Induction of Anthocyanin Accumulation by Cytokinins in Arabidopsis thaliana

LIGHT-INDUCED RICE1 Regulates Light-Dependent Attachment of LEAF-TYPE FERREDOXIN-NADP+ OXIDOREDUCTASE to the Thylakoid Membrane in Rice and Arabidopsis

A Thiol Protease and an Anionic Peroxidase Are Induced by Lowering Cytokinins during Callus Growth in Petunia

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LIGHT-INDUCED RICE1 Regulates Light-Dependent Attachment of LEAF-TYPE FERREDOXIN-NADP⁺ OXIDOREDUCTASE to the Thylakoid Membrane in Rice and Arabidopsis