Abstract
The transition from young carbon-importing sink leaves of higher plants to mature carbon-exporting source leaves is paralleled by a complete reversal of phloem function. While sink-leaf phloem mediates the influx of reduced carbon from older source leaves and the release of this imported carbon to the sink-leaf mesophyll, source-leaf phloem catalyzes the uptake of photoassimilates into companion cells (CCs) and sieve elements (SEs) and the net carbon export from the leaf. Phloem loading in source leaves with sucrose, the main or exclusive transport form for fixed carbon in most higher plants, is catalyzed by plasma membrane-localized sucrose transporters. Consistent with the described physiological switch from sink to source, the promoter of the Arabidopsis AtSUC2 gene is active only in source-leaf CCs of Arabidopsis or of transgenic tobacco (Nicotiana tabacum). For the identification of regulatory elements involved in this companion cell-specific and source-specific gene expression, we performed detailed analyses of the AtSUC2 promoter by truncation and mutagenesis. A 126-bp promoter fragment was identified, which seems to contain these fragments and which drives AtSUC2-typical expression when combined with a 35S minimal promoter. Within this fragment, linker-scanning analyses revealed two cis-regulatory elements that were further characterized as putative binding sites for transcription factors of the DNA-binding-with-one-finger or the homeo-domain-leucine-zipper families. Similar or identical binding sites are found in other genes and in different plant species, suggesting an ancient regulatory mechanism for this important physiological switch.
Similar content being viewed by others
Abbreviations
- AtSUC2 :
-
Arabidopsis thaliana SUCROSE TRANSPORTER 2 gene
- CC:
-
Companion cell
- CmGAS1 :
-
Cucumis melo GALACTIONOL SYNTHASE 1 gene
- DOF:
-
DNA-binding-with-one-finger
- GFP:
-
Green fluorescent protein
- GUS:
-
β-Glucuronidase
- HD-Zip:
-
Homeo-domain-leucine-zipper
- IC:
-
Intermediary cell
- nt:
-
Nucleotides
- ORF:
-
Open reading frame
- PCR:
-
Polymerase chain reaction
- RFOs:
-
Raffinose family oligosaccharides
- SE:
-
Sieve element
- wt:
-
Wild type
References
An H, Roussot C, Suarez-Lopez P, Corbesier L, Vincent C, Pineiro M, Hepworth S, Mouradov A, Justin S, Turnbull C, Coupland G (2004) CONSTANS acts in the phloem to regulate a systemic signal that induces photoperiodic flowering of Arabidopsis. Development 131:3615–3626
Ariel FD, Manavella PA, Dezar CA, Chan RL (2007) The true story of the HD-Zip family. Trends Plant Sci 12:419–426
Avery GS (1933) Structure and development of the tobacco leaf. Am J Bot 20:565–592
Ayre BG, Blair JE, Turgeon R (2003) Functional and phylogenetic analyses of a conserved regulatory program in the phloem of minor veins. Plant Physiol 133:1229–1239
Baima S, Nobili F, Sessa G, Lucchetti S, Ruberti I, Morelli G (1995) The expression of the Athb–8 homeobox gene is restricted to provascular cells in Arabidopsis thaliana. Development 121:4171–4182
Beebe DU, Turgeon R (1992) Localization of galactinol, raffinose, and stachyose synthesis in Cucurbita pepo leaves. Planta 188:354–361
Becker D, Kemper E, Schell J, Masterson R (1992) New plant binary vectors with selectable markers located proximal to the left T-DNA border. Plant Mol Biol 20:1195–1197
Brandt S, Kehr J, Walz C, Imlau A, Willmitzer L, Fisahn J (1999) Technical advance: A rapid method for detection of plant gene transcripts from single epidermal, mesophyll and companion cells of intact leaves. Plant J 20:245–250
Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16:735–743
Ding B, Parthasarathy MV, Niklas K, Turgeon R (1988) A morphometric analysis of the phloem-unloading pathway in developing tobacco leaves. Planta 176:307–318
Dunn MA, White AJ, Vural S, Hughes MA (1998) Identification of promoter elements in a low-temperature-responsive gene (blt4.9) from barley (Hordeum vulgare L.). Plant Mol Biol 38:551–564
Freitas RL, Carvalho CM, Fietto LG, Loureiro ME, Almeida AM, Fontes EP (2007) Distinct repressing modules on the distal region of the SBP2 promoter contribute to its vascular tissue-specific expression in different vegetative organs. Plant Mol Biol 65:603–614
Gatz C, Frohberg C, Wendenburg R (1992) Stringent repression and homogeneous de-repression by tetracycline of a modified CaMV 35S promoter in transgenic tobacco plants. Plant J 2:397–404
Haritatos E, Ayre BG, Turgeon R (2000) Identification of phloem involved in assimilate loading in leaves by the activity of the galactinol synthase promoter. Plant Physiol 123:929–937
Haupt S, Oparka KJ, Sauer N, Neumann S (2001) Macromolecular trafficking between Nicotiana tabacum and the holoparasite Cuscuta reflexa. J Exp Bot 52:173–177
Higo K, Ugawa Y, Iwamoto M, Korenaga T (1999) Plant cis-acting regulatory DNA elements (PLACE) database: 1999. Nucleic Acids Res 27:297–300
Hanahan D (1983) Studies on transformation of E. coli with plasmids. J Mol Biol 166:557–580
Holsters M, Silva B, Van Vliet F, Genetello C, De Block M, Dhaese P, Depicker A, Inze D, Engler G, Villarroel R, Van Montagu M, Schell J (1980) The functional organization of the nopaline Agrobacterium tumefaciens plasmid pTiC58. Plasmid 3:212–230
Hoth S, Schneidereit A, Lauterbach C, Scholz-Starke J, Sauer N (2005) Nematode infection triggers the de novo formation of unloading phloem that allows macromolecular trafficking of green fluorescent protein into syncytia. Plant Physiol 138:383–392
Imlau A, Truernit E, Sauer N (1999) Cell-to-cell and long-distance trafficking of the green fluorescent protein in the phloem and symplastic unloading of the protein into sink tissues. Plant Cell 11:309–322
Ivashikina N, Deeken R, Ache P, Kranz E, Pommerrenig B, Sauer N, Hedrich R (2003) Isolation of AtSUC2 promoter-GFP-marked companion cells for patch-clamp studies and expression profiling. Plant J 36:931–945
Juergensen K, Scholz-Starke J, Sauer N, Hess P, van Bel AJ, Grundler FM (2003) The companion cell-specific Arabidopsis disaccharide carrier AtSUC2 is expressed in nematode-induced syncytia. Plant Physiol 131:61–69
Keller F, Pharr DM (1996) Metabolism of carbohydrates in sinks and sources: galactosyl-sucrose oligosaccharides. In: Zamski E, Schaffer AA (eds) Photoassimilate distribution in plants and crops: source–sink relationships. Marcel Dekker, New York, pp 157–183
Lin MK, Belanger H, Lee Y-J, Varkonyi-Gasic E, Taoka K-I, Miura E, Xoconostle-Cázares B, Gendler K, Jorgensen RA, Phinney B, Lough TJ, Lucas WJ (2007) FLOWERING LOCUS T protein may act as the long-distance florigenic signal in the cucurbits. Plant Cell 19:1488–1506
Martens HJ, Roberts AG, Oparka KJ, Schulz A (2006) Quantification of plasmodesmatal ER coupling between sieve elements and companion cells using fluorescence redistribution after photobleaching (FRAP). Plant Physiol 142:471–480
Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15:473–497
Oparka KJ, Roberts AG, Boevink P, Santa Cruz S, Roberts IM, Pradel KS, Imlau A, Kotlizky G, Sauer N, Epel BL (1999) Simple, but not branched, plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves. Cell 97:743–754
Pommerrenig B, Barth I, Niedermeier M, Kopp S, Schmid J, Dwyer RA, McNair RJ, Klebl F, Sauer N (2006) Common plantain. A collection of expressed sequence tags from vascular tissue and a simple and efficient transformation method. Plant Physiol 142:1427–1441
Roberts AG, Santa Cruz S, Roberts IM, Prior DAM, Turgeon R, Oparka KJ (1997) Phloem unloading in sink leaves of Nicotiana benthamiana: comparison of a fluorescent solute with a fluorescent virus. Plant Cell 9:1381–1396
Sauer N, Stolz J (1994) SUC1 and SUC2: two sucrose transporters from Arabidopsis thaliana. Expression and characterization in baker’s yeast and identification of the histidine-tagged protein. Plant J 6:67–77
Searle I, He Y, Turck F, Vincent C, Fornara F, Krober S, Amasino RA, Coupland G (2006) The transcription factor FLC confers a flowering response to vernalization by repressing meristem competence and systemic signaling in Arabidopsis. Genes Dev 20:898–912
Sessa G, Morelli G, Ruberti I (1993) The Athb-1 and -2 HD-Zip domains homodimerize forming complexes of different DNA binding specificities. EMBO J 12:3507–3517
Sessa G, Steindler C, Morelli G, Ruberti I (1998) The Arabidopsis Athb-8, -9 and -14 genes are members of a small gene family coding for highly related HD-ZIP proteins. Plant Mol Biol 38:609–622
Skirycz A, Reichelt M, Burow M, Birkemeyer C, Rolcik J, Kopka J, Zanor MI, Gershenzon J, Strnad M, Szopa J, Mueller-Roeber B, Witt I (2006) DOF transcription factor AtDof1.1 (OBP2) is part of a regulatory network controlling glucosinolate biosynthesis in Arabidopsis. Plant J 47:10–24
Söderman E, Hjellström M, Fahleson J, Engström P (1999) The HD-Zip gene ATHB6 in Arabidopsis is expressed in developing leaves, roots and carpels and up-regulated by water deficit conditions. Plant Mol Biol 40:1073–1083
Stadler R, Lauterbach C, Sauer N (2005a) Cell-to-cell movement of GFP reveals post-phloem transport in the outer integument and identifies symplastic domains in Arabidopsis seeds and embryos. Plant Physiol 139:701–712
Stadler R, Sauer N (1996) The Arabidopsis thaliana AtSUC2 gene is specifically expressed in companion cells. Bot Acta 109:299–306
Stadler R, Wright KM, Lauterbach C, Amon G, Bahrtz M, Feuerstein A, Oparka KJ, Sauer N (2005b) Expression of GFP-fusions in Arabidopsis companion cells reveals non-specific protein trafficking into sieve elements and identifies a novel post-phloem domain in roots. Plant J 41:319–331
Thompson MV, Wolniak SM (2008) A plasma membrane-anchored fluorescent protein fusion illuminates sieve element plasma membranes in Arabidopsis thaliana and Nicotiana tabacum. Plant Physiol 146:1599–1610
Truernit E, Sauer N (1995) The promoter of the Arabidopsis thaliana SUC2 sucrose-H+ symporter gene directs expression of β-glucuronidase to the phloem: evidence for phloem loading and unloading by SUC2. Planta 196:564–570
Turgeon R (1984) Termination of nutrient import and development of vein loading capacity in albino tobacco leaves. Plant Physiol 76:45–48
Turgeon R (1987) Phloem unloading in tobacco sink leaves: insensitivity to anoxia indicates a symplastic pathway. Planta 171:73–81
Turgeon R (1989) The sink–source transition in leaves. Annu Rev Plant Physiol Plant Mol Biol 40:119–138
Ward JM, Cufr CA, Denzel MA, Neff MM (2005) The Dof transcription factor OBP3 modulates phytochrome and cryptochrome signaling in Arabidopsis. Plant Cell 17:475–485
Wright KM, Roberts AG, Martens HJ, Sauer N, Oparka KJ (2003) Structural and functional vein maturation in developing tobacco leaves in relation to AtSUC2 promoter activity. Plant Physiol 131:1555–1565
Yanagisawa S (1995) A novel DNA-binding domain that may form a single zinc finger motif. Nucleic Acids Res 23:3403–3410
Yanagisawa S, Izui K (1993) Molecular cloning of two DNA-binding proteins of maize that are structurally different but interact with the same sequence motif. J Biol Chem 268:16028–16036
Yanagisawa S, Schmidt RJ (1999) Diversity and similarity among recognition sequences of Dof transcription factors. Plant J 17:209–214
Zhang B, Chen W, Foley RC, Büttner M, Singh KB (1995) Interactions between distinct types of DNA binding proteins enhance binding to ocs element promoter sequences. Plant Cell 7:2241–2252
Zhao C, Craig JC, Petzold HE, Dickerman AW, Beers EP (2005) The xylem and phloem transcriptomes from secondary issues of the Arabidopsis root-hypocotyl. Plant Physiol 138:803–818
Zhao Y, Liu Q, Davis RE (2004) Transgene expression in strawberries driven by a heterologous phloem-specific promoter. Plant Cell Rep 23:224–230
Zhou DX (1999) Regulatory mechanism of plant gene transcription by GT-elements and GT-factors. Trends Plant Sci 4:210–214
Acknowledgments
This work was supported by the Deutsche Forschungsgemeinschaft (SFB473/A3) to N.S.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Schneidereit, A., Imlau, A. & Sauer, N. Conserved cis-regulatory elements for DNA-binding-with-one-finger and homeo-domain-leucine-zipper transcription factors regulate companion cell-specific expression of the Arabidopsis thaliana SUCROSE TRANSPORTER 2 gene. Planta 228, 651–662 (2008). https://doi.org/10.1007/s00425-008-0767-4
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00425-008-0767-4