JXB Advance Access originally published online on July 12, 2005
Journal of Experimental Botany 2005 56(419):2487-2494; doi:10.1093/jxb/eri241
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RESEARCH PAPER |
A versatile promoter for the expression of proteins in glandular and non-glandular trichomes from a variety of plants
1Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, CSIC-Universidad de Sevilla, Avda Américo Vespucio, 49, 41092-Sevilla, Spain
2Laboratoire BVpam (Biotechnologies Végétales, plantes aromatiques et médicinales), Faculté des Sciences et Techniques, Université Jean Monnet, 23, rue du Docteur Michelon, F-42023 Saint-Etienne Cedex 02, France
* To whom correspondence should be addressed. Fax: +34 954460065. E-mail: lromero{at}ibvf.csic.es
Received 18 March 2005; Accepted 2 June 2005
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Abstract |
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A DNA regulatory fragment was isolated from the promoter region of the OASA1 gene, encoding the cytosolic O-acetylserine(thiol)lyase enzyme that is highly expressed in Arabidopsis thaliana trichomes. This DNA fragment has been named an ATP fragment and comprises 1435 bp of the genomic region upstream of the OASA1 gene and 375 bp of the transcriptional initiation start site containing the first intron of the gene. The ATP fragment, fused to the green fluorescent protein (GFP) and ß-glucuronidase (GUS) reporter genes, is able to drive high-level gene expression in A. thaliana trichomes. Deletion analysis of the ATP fragment determined that the region from –266 to –66 contains regulatory elements required for trichome expression. In addition, the region from +112 to +375, comprising the first intronic region of the gene, is also essential for trichome gene expression. Expression of the full-length ATP fragment in tobacco and peppermint shows that this fragment is also able to drive expression in glandular trichomes and suggests additional biotechnological applications for this promoter.
Key words: Arabidopsis, confocal microscopy, peppermint, tobacco
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Introduction |
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TopAbstractIntroductionMaterials and methodsResults and discussionReferences |
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Trichomes are specialized unicellular or multicellular structures derived from the epidermal cell layer. Unicellular non-glandular trichomes, such as those present in A. thaliana, are not able to produce or secrete phytochemicals but may function as defensive physical structures against herbivores (Eisner et al., 1998
), as sinks for toxic heavy metals and xenobiotics (Gutiérrez-Alcalá et al., 2000; Domínguez-Solís et al., 2004), and in regulating water absorption (Werker, 2000). Biotechnological applications of non-glandular trichomes have not been widely explored except in the case of cotton ovule trichomes that have agricultural importance in the production of fibres with enormous commercial value (Kim and Triplett, 2001).
Multicellular trichomes can be found in many different species and often form glands that secrete phytochemical compounds (e.g. organic acids, polysaccharides, terpenes, or salt) as well as secondary compounds such as those produced in trichome exudates (e.g. terpenoids, flavonoids, and phenylpropanoids) (Duke et al., 2000). Glandular trichomes show variously forms and can be unicellular or multicellular and morphological distinction can be observed between the apical and the basal part of the glands (Werker, 2000). Glandular secretory trichomes have potential biotechnological applications as a result of the great variety of phytochemical molecules produced. Many of these molecules have significant commercial application in the production of flavours and fragrances, such as vanillin and benzaldehyde (Krings and Berger, 1998), the pharmaceutical industry, such as artemisinin (Mahlberg and Kim, 1992; Li et al., 2002), and in host defence or plant–plant allelopathy (Werker, 2000). Extensive references about secreted molecules from plant trichomes are available (Callow, 2000; Wagner et al., 2004). Approaches for the exploitation of trichomes, for both commercial and agronomic purposes, require the application of appropriate molecular tools to attempt to modify the metabolic pathways in trichome cells. One of these tools is the development of trichome-specific promoters to direct gene expression in these cells. Although strong and constitutive promoters, such as the 35S CaMV promoter are also highly expressed in trichomes, it could be problematic for expressing a potentially cytotoxic protein. The main advantage of a trichome-specific versus a constitutive promoter is the capability to bioengineer biochemical pathways present only in trichome cells without altering biochemical pathways in other tissues and to avoid affecting plant growth or productivity. This effect has recently been tested by the expression of a defence-related gene in wheat epidermis under the control of the epidermal-specific GstA1 promoter from wheat. In this work, it was observed that tissue-specific expression of a potentially harmful transgene was superior to ubiquitous expression throughout the plant body (Alpeter et al., 2005).
Obtaining a trichome-specific promoter has been attempted after isolation of the LTP3 gene promoter from cotton and the CYP71D16 gene promoter from tobacco. These promoters were able to direct GUS expression, the former in non-glandular and the latter in glandular trichomes (Liu et al., 2000; Wang et al., 2002). The CYP71D16 promoter was also successfully used to suppress cembratrieneols in trichome exudates and to reduce aphid infection in tobacco (Wang et al., 2004a). However, a universal trichome promoter, able to direct high-level expression in a wide range of trichomes and plant species, has not been reported.
In this work, the isolation of a DNA regulatory fragment, able preferentially to direct high-level expression of GFP and GUS reporter genes in non-glandular trichomes from A. thaliana, and in glandular trichomes from tobacco and peppermint, is reported. This trichome regulatory element was isolated from the OASA1 gene from A. thaliana, encoding the cytosolic O-acetylserine(thiol)lyase enzyme involved in cysteine biosynthesis (Barroso et al., 1995). This gene has been demonstrated, by in situ hybridization, to have high-level gene expression in A. thaliana trichomes (Gotor et al., 1997; Gutiérrez-Alcalá et al., 2000).
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Materials and methods |
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TopAbstractIntroductionMaterials and methodsResults and discussionReferences |
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Plant material and growth conditions
Wild-type Arabidopsis thaliana was grown on moist vermiculite supplemented with Hoagland medium or in soil media at 20 °C in the light and 18 °C in the dark, under a 16/8 h white light/dark photoperiod, as previously described by Dominguez-Solis et al. (2001)
. Transformed or wild-type tobacco (Nicotiana tabacum cv. W38) seeds were grown in soil media at 26 °C with a 16 h photoperiod. Peppermint (Menthaxpiperita L.) cultures were started from rhizome explants and maintained in growth chambers at 25 °C with a 16/8 h photoperiod.
DNA cloning and plasmid construction
The ATP regulatory sequence was isolated by screening an A. thaliana genomic DNA library (
500 000 pfu) constructed in the EMBL3 vector using [
-32P]dCTP-labelled OASA1 cDNA (Barroso et al., 1995). After analysis of several positive clones, a 2692-nucleotide DNA fragment, containing the promoter and 5' end of the gene, was isolated and cloned into the pBluescript KSII vector at the KpnI restriction site. This clone was used as a template for PCR to obtain a shortened DNA fragment using the following primers: forward primer (5'-ATGCCCGGGTACCTACTGCAGTCCGGT-3') containing a SmaI restriction site (underlined); reverse primer (5'-ATGGGATCCCGAGGCCATGATTCAAGC-3') containing a BamHI restriction site (underlined). The PCR-amplified fragment was digested with SmaI and BamHI and gel-purified. This fragment was ligated into the pBI121 vector (Clontech, USA), previously digested with HindIII, treated with Klenow enzyme, and digested again with BamHI to release the 35S promoter. The inserted DNA regulatory sequence consists of 1810 nucleotides and corresponds to the sequence between nucleotides 8 521 846 and 8 520 037 of A. thaliana chromosome 4. The resulting vector was named pATP-GUS. The GUS sequence was removed from the pATP-GUS vector by digestion with BamHI and SstI prior to replacement with the smGFP gene (Davis and Viestra, 1998) at the same restriction sites to yield pATP-GFP.
Primer extension analysis
Total A. thaliana RNA was extracted from root tissue by using the RNeasy Plant Mini Kit (Qiagen GmbH, Germany). The 5'-end of the RNA was mapped by combining 2.5 pmol PE primer (5'-GAAACCGGCAGAG GAATAAGCAAGTG-3') and 10 µg RNA in a 10 µl final volume containing 1 mM TRIS–HCl (pH 8), 1 mM EDTA, and 10 mM KCl. The mixture was incubated at 100 °C for 10 min, cooled to 47 °C, and further incubated for 1 h. The PE primer was extended using 500 U SuperScript II reverse transcriptase in the following reaction mix: 10 mM DTT, 25 µCi [-32P] dCTP (3000 Ci mmol–1), 0.18 mM of dNTP mix (dATP, dGTP, dTTP) and SuperScript II enzyme buffer. After an incubation of 1 h at 47 °C, 2 U of DNase-free RNase was added and the reaction incubated 15 min at 37 °C. The reaction product was separated on a denaturing sequencing gel (6% polyacrylamide) in parallel with the sequencing reaction products of the ATP fragment using the PE primer.
Transformation of Arabidopsis, tobacco, and peppermint plants
For plant transformation, the chimeric gene constructs were transformed into Agrobacterium tumefaciens strain C58pMP90 (Koncz and Schell, 1986). A. thaliana (ecotype Columbia) was transformed by dipping the developing floral tissues into a solution containing the A. tumefaciens strain, 5% sucrose, and 0.005% (v/v) surfactant Silwet L-77, as previously described by Clough and Bent (1998). Transgenic plants were recovered by selecting seeds on solid MS medium containing 50 mg l–1 kanamycin. Copy number was assessed by monitoring the segregation of resistance to kanamycin. T3, or subsequent generations of each line, were used for the experiments described in this paper.
M.xpiperita L. explants were also transformed with A. tumefaciens strain C58pMP90 containing the pATP-GUS or GFP constructs and generated according to the methods described by Diemer et al. (1998). Tobacco (N. tabacum cv. W38) leaf discs were used for transformation using standard procedures (Gotor et al., 1993).
Analysis of the GFP and GUS reporter genes
The accumulation of the GFP reporter protein was analysed in vivo by laser confocal microscopy. Leaves were carefully cut into small pieces (4–9 mm2) and mounted onto a slide using a spacer between the slide and coverslip to avoid crushing the trichomes. Samples were observed using Leica HCX PLAN-APO 63x 1.4 NA or HCX PLAN-APO 40x 1.25 NA oil immersion objectives attached to a Leica TCS SP2 spectral confocal microscope (Leica Microsystems, Germany). GFP was imaged using the 488 nm line of an argon ion laser, either in single confocal optical sections or serial optical sections of leaves. Emitted light was collected through a triple dichroic beam-splitter (TD 488/543/633) and simultaneously detected after spectral separation in the 493–540 nm range on the PMT1 for GFP imaging (pseudocoloured green) and in the 541–600 nm range on the PMT2 for chloroplast and cell wall autofluorescence (pseudocoloured red). Manual unmixing eliminated the strong chloroplast signal, which leaked from the red channel into the green. Image montages were assembled using PhotoshopTM (Adobe Systems, Mountain View, CA, USA).
The histochemical assay for GUS enzyme activity was carried out according to the procedure of Jefferson et al. (1987). Leaves were carefully cut into small pieces (4–9 mm2) and washed with 70% ethanol. The tissues were immersed in X-Gluc substrate solution containing 50 mM sodium phosphate buffer (pH 7.0), 0.5 mg ml–1 5-bromo-4-chloro-3–indolylglucuronide (X-Gluc), and 0.05% Triton X-100, and then incubated at 37 °C for 1 h (or overnight). After incubation, the stained tissues were washed several times with 70% ethanol to remove residual chlorophyll, and visualized using an Olympus SZ 4045TR stereomicroscope.
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Results and discussion |
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The ATP fragment is able to confer a high level of gene expression in trichomes
It has been observed that the ATCYS-3A gene (At4g14880) from A. thaliana was preferentially highly expressed in leaf and stem trichomes (Gotor et al., 1997
; Gutiérrez-Alcalá et al., 2000). Based on this observation, the DNA regulatory fragment of this gene was isolated. The ATCYS-3A gene has been renamed OASA1 by others, and therefore, this nomenclature has been selected in the present article (Jost et al., 2000). The DNA regulatory fragment is 1810 nucleotides in length and is named an ATP fragment. The isolated fragment consists of 1435 bp of the genomic region upstream of OASA1, and 375 bp of the 5'-UTR containing the first exon, the first intron, and 22 bp of the second exon of the gene (Fig. 1A). The transcription initiation site was determined by primer extension being the first nucleotide numbered +1 (Fig. 1B), and the intron/exon boundaries were determined by comparison with the cDNA sequence (Barroso et al., 1995). The ATP fragment was fused to the green fluorescent protein (GFP) and ß-glucuronidase (GUS) reporter genes and the constructs for plant transformation were named pATP-GFP and pATP-GUS, respectively. Several transgenic A. thaliana plants were obtained and homozygous lines analysed by laser confocal microscopy for in vivo GFP detection or by light microscopy for histochemical GUS detection. Intact leaves from 2-week-old A. thaliana plants were analysed and strong GFP fluorescent emissions (pseudocoloured green) were largely detected in the trichomes but not in control plants (Fig. 2A, B). GFP was observed inside the nuclei of trichomes in a thin layer of cytoplasm underneath the cell wall, and in cytoplasmic strands across the vacuoles. Weaker signals were also detected in a thin layer of cytoplasm in the epidermal cells, although at a lesser intensity than in trichomes (Fig. 2B, C). This observation is in agreement with studies of in situ localization of the OASA1 mRNA in leaves, showing a low constitutive expression in epidermal and mesophyll cells (Gotor et al., 1997). Wild-type plants did not show any fluorescence under GFP band detection (493–540 nm) and only showed autofluorescence in the cell walls of the epidermal and trichome cells and in the chloroplasts of mesophyll cells (pseudocoloured red) (Fig. 2A). The same results were obtained by histochemical staining of the ß-glucuronidase activity in the pATP-GUS transformed lines (Fig. 2D, E). High GUS activity was observed in the basal and central regions of the leaf trichomes and a very low activity was detected in a thin layer of cytoplasm in the epidermal cells. Therefore, the ATP fragment is largely expressed but is not trichome-specific in A. thaliana.
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ATP fragment deletion analysis
Database searches for regulatory elements in the ATP fragment by PLACE (http:://www.dna.affrc.go.jp/htdocs/PLACE/) revealed a putative TATA box at the –48 position, several MYB recognition sites, and other putative regulatory binding sites. MYB factors are transcriptional regulators involved in developmental control, cell fate, and identity, such as GLABROUS1, which control trichome formation (Oppenheimer et al., 1991
). These MYB recognition factors have been detected in the promoters of trichome-expressed genes, such as in cotton fibres LTP3 and RDL1 and tobacco CYP71D16 (Liu et al., 2000; Wang et al., 2002, 2004b). Although there are no studies about cis-responsive elements in the LTP3 and CYP71D16 promoters involved in trichome expression, the essential role of the L1 box and MYB binding motif in trichome expression, localized to the RDL1 promoter region, has previously been described (Wang et al., 2004b).
To identify the regulatory regions involved in trichome expression in the ATP fragment, successive 5' and 3' deletions of this fragment have been performed to generate seven fusion constructs of GFP (Fig. 3A). In the ATP2 deletion, a largely 5'-upstream fragment containing the adjacent genes of OASA1 has been removed. This deletion contains 419 bp of the intergenic region between the OASA1 and ferredoxin genes and 375 bp of the 5'-UTR. The ATP2I, ATP2II, and ATP6 constructs are additional deletions at the 5'-end. Fluorescence analyses in several transgenic lines of each deletion construct showed that ATP and ATP2 drive the same expression patterns in the A. thaliana trichome. ATP2I and ATP2II deletion constructs also showed similar GFP fluorescence intensities compared with the full-length promoter in trichomes, while for ATP6 lines, no detectable fluorescence was observed (Fig. 3). Therefore, the DNA region from –269 to –66 contains the regulatory elements required for trichome expression (Fig. 3Be). Deletion analysis at the 3'-end of the ATP fragment helped identify a domain from +112 to +375 that is also essential for trichome expression and is comprised mainly of the first intron localized in the 5'-UTR (Fig. 3Bf). This localization of regulatory elements in the ATP fragment is similar to that obtained in the promoter region of the RDL1 gene. Database searches for regulatory elements in these ATP regions by PLACE showed that the region between –268 to –66 contains four MYB motifs, two of which are separated by 16 nucleotides. However, this analysis does not predict any L1 box motif within the RDL1 promoter to be essential for trichome expression (Wang et al., 2004b).
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The presence of introns at the 5'-UTR region is a common feature of several A. thaliana trichome-expressed genes, such as the MADS-box AGL16 gene (Alvarez-Buylla et al., 2000
), the ionizing radiation-induced GR1 gene (Deveaux et al., 2000), the metallothionein MT2a gene (García-Hernández et al., 1998), and the wound-responsive WR3 gene (León et al., 1998). This 5'-UTR region can play an important role in the regulation of gene expression by regulating mRNA stability, the efficiency of translation, or can directly impact transcriptional regulation (Bailey-Serres and Gallie, 1998). It has been demonstrated that enhancer elements present in the introns of the 5'-UTR are involved in transcriptional regulation (Maas et al., 1991; Gidekel et al., 1996; Plesse et al., 2001; Morello et al., 2002). However, introns may influence and enhance eukaryotic gene expression by multiple mechanisms (Le Hir et al., 2003). The transcription factors GL1 and GaMYB2 contain a MYB motif that is present in the first intron of these genes that acts as an enhancer element in trichome cells (Wang et al., 2004b). The intron region of the OASA1 gene present in the ATP fragment also appears to be essential for trichome expression, since the ATP3 construct did not show GFP fluorescence (Fig. 3Bf). PLACE searches indicated that this intron region between +112 to +375 contains three putative MYB motifs, although the position of these motifs was not conserved when compared with the intronic elements of GL1 and GaMYB2 that are localized at the same position (i.e. 22–23 bp upstream of the second exon) (Wang et al., 2004b).
The Arabidopsis ATP fragment is functional in glandular trichomes
A. thaliana trichomes are unicellular, non-secretory structures. Despite their morphological differences with the glandular trichomes, the authors wanted to test whether the ATP fragment could drive high-level gene expression in these structures. M.xpiperita leaf discs were transformed with the pATP-GFP and pATP-GUS constructs (via A. tumefaciens) and several kanamycin-resistant peppermint plants were generated. Peppermint leaves contain two types of secretory trichomes, peltate and capitate glands. Peltate trichomes are composed of a basal cell, a short stalk cell, and a broad head that consists of eight secretory cells arranged in a single layer (Amelunxen, 1965). The capitate trichomes consist of a basal cell, one stalk cell, and a head composed of one or two cells (Fahn, 2000). GFP analysis of the transformed plants showed high levels of expression in the head and stalk cells of the capitate trichomes and in the head of the peltates. Other epidermal and mesophyll cells did not show detectable GFP fluorescence (Fig. 4A–H). Analysis of the pATP-GUS-transformed peppermint lines confirmed the same pattern of expression in capitate and peltate trichomes (Fig. 4I–K) with, sometimes, a little diffusion of the blue colour in the surrounding epidermis.
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N. tabacum plants containing glandular trichomes were also transformed with the two constructs. Such glandular trichomes comprise a very long-stalk and multicellular head. Due to the strong autofluorescence of these trichomes, in vivo analysis of the GFP reporter could not be performed. However, analysis of GUS activity in the transformed lines showed significant expression in all trichome cells with a very strong signal in the glandular head (Fig. 4L–M).
In conclusion, the isolated ATP fragment is able to confer high levels of gene expression in different types of plant trichomes. Biotechnological applications of this promoter on disease resistance have been attempted by expression of glucanase enzymes from Trichoderma harzianum, showing antifungal activities, under control of the ATP fragment. Stable high-level expression of these defence-related genes preferentially in the trichome shows increased resistance to necrotrophic fungi (L Calo et al., unpublished results). Its additional functionality in glandular trichomes suggests potential biotechnological applications for this regulatory DNA fragment. In peppermint, essential oils are stocked between the cell wall and the detached cuticle with a very low level of evaporation (Gershenzon et al., 2000). By contrast, in tobacco, essential oils and polysaccharides pour directly out of the head-cells, giving a resin-like liquid on the leaves. Such differences in the chemical secretion pathway could permit very fine-tuning of the biotechnological strategies.
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Acknowledgements |
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This work was funded by grants from DGI (BIO2000-0270 and BIO2003-0168) and the University of Seville (USE-Monte 2000/101) to LCR and a DGI grant (BOS2001-1084) to CG. LC is indebted to the MEC, CSIC, and COST-829 Action for fellowship support.
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References |
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TopAbstractIntroductionMaterials and methodsResults and discussionReferences |
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Alpeter F, Vershney A, Abderhalden O, Douchkov D, Sautter C, Kumlehn J, Dudler R, Schweizer P. 2005. Stable expression of a defense-related gene in wheat epidermis under transcriptional control of a novel promoter confers pathogen resistance. Plant Molecular Biology 57, 271–283.[CrossRef][ISI][Medline]
Alvarez-Buylla ER, Liljegren SJ, Pelaz S, Gold SE, Burgeff C, Ditta GS, Vergara-Silva F, Yanofsky MF. 2000. MADS-box gene evolution beyond flowers: expression in pollen, endosperm, guard cells, roots, and trichomes. The Plant Journal 24, 457–466.[CrossRef][ISI][Medline]
Amelunxen F. 1965. Elektronenmikroskopische Untersuchungen an des Drüsenschuppen von Mentha piperita L. Planta Medica 13, 457–473.
Bailey-Serres J, Gallie DR. 1998. A look beyond transcription. Mechanisms determining mRNA stability and translation in plants. American Society of Plant Biology, 1–183.
Barroso C, Vega JM, Gotor C. 1995. A new member of the cytosolic O-acetylserine(thiol)lyase gene family from Arabidopsis thaliana. FEBS Letters 363, 1–5.[CrossRef][ISI][Medline]
Callow JA. 2000. Plant trichomes. Advances in botanical research, Vol. 31 (Hallahan DL, Gray JC, eds). San Diego: Academic Press.
Clough SJ, Bent AF. 1998. Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. The Plant Journal 16, 735–743.[CrossRef][ISI][Medline]
Davis SJ, Viestra RD. 1998. Soluble, highly fluorescent variants of green fluorescent protein (GFP) for use in higher plants. Plant Molecular Biology 36, 521–528.[CrossRef][ISI][Medline]
Deveaux Y, Alonso B, Pierrugues O, Godon C, Kazmaier M. 2000. Molecular cloning and developmental expression of AtGR1, a new growth-related Arabidopsis gene strongly induced by ionizing radiation. Radiation Research 154, 355–364.[CrossRef][ISI][Medline]
Diemer F, Jullien F, Faure O, Moja S, Colson M, Matthys-Rochon E, Caissard JC. 1998. High efficiency transformation of peppermint (Menthaxpiperita L.) with Agrobacterium tumefaciens. Plant Science 136, 101–108.
Domínguez-Solís JR, Gutiérrez-Alcalá G, Vega JM, Romero LC, Gotor C. 2001. Cytosolic O-acetylserine(thiol)lyase is regulated by heavy metals and can function in cadmium tolerance. Journal of Biological Chemistry 276, 9297–9302.
Domínguez-Solís JR, López-Martín MC, Ager FJ, Ynsa MD, Romero LC, Gotor C. 2004. Increased cysteine availability is essential for cadmium tolerance and accumulation in Arabidopsis thaliana. Plant Biotechnology Journal 2, 469–476.[CrossRef][Medline]
Duke SO, Canel C, Rimando AM, Tellez MR, Duke MV, Paul RN. 2000. Current and potential exploitation of plant glandular trichome productivity. In: Hallahan DL, Gray JC, eds. Advances in botanical research, Vol. 31. San Diego: Academic Press, 121–151.
Eisner T, Eisner M, Hoebeke ER. 1998. When defense backfires: detrimental effect of a plant's protective trichome on an insect beneficial to the plant. Proccedings of the National Academy of Sciences, USA 95, 4410–4414.
Fahn A. 2000. Structure and function of secretory cells. In: Hallahan DL, Gray JC, eds. Advances in botanical research, Vol. 31. San Diego: Academic Press, 37–75.
García-Hernández M, Murphy A, Taiz L. 1998. Metallothioneins 1 and 2 have distinct but overlapping expression patterns in Arabidopsis. Plant Physiology 118, 387–397.
Gershenzon J, McConkey ME, Croteau RB. 2000. Regulation of monoterpene accumulation in leaves of peppermint. Plant Physiology 122, 205–213.
Gidekel M, Jimenez B, Herrera-Estrella L. 1996. The first intron of the Arabidopsis thaliana gene coding for elongation factor 1ß contains an enhancer-like element. Gene 170, 201–206.[CrossRef][ISI][Medline]
Gotor C, Cejudo FJ, Barroso C, Vega JM. 1997. Tissue specific expression of ATCYS-3A, a gene encoding the cytosolic isoform of O-acetylserine(thiol)lyase in Arabidopsis. The Plant Journal 11, 347–352.[CrossRef][ISI][Medline]
Gotor C, Romero LC, Inouye K, Lam E. 1993. Analysis of three tissue-specific elements from the wheat Cab-1 enhancer. The Plant Journal 3, 509–518.[CrossRef][ISI][Medline]
Gutiérrez-Alcalá G, Gotor C, Meyer AJ, Fricker M, Vega JM, Romero LC. 2000. Glutathione biosynthesis in Arabidopsis trichome cells. Proceedings of the National Academy of Sciences, USA 97, 11108–11113.
Jefferson RA, Kavanagh TA, Bevan MW. 1987. GUS fusions: ß-glucuronidase as a sensitive and versatile fusion marker in higher plants. EMBO Journal 6, 3901–3907.[ISI][Medline]
Jost R, Berkowitz O, Wirtz M, Hopkins L, Hawkesford MJ, Hell R. 2000. Genomic and functional characterization of the oas gene familyencoding O-acetylserine (thiol) lyases, enzymes catalysing the final step in cysteine biosynthesis in Arabidopsis thaliana. Gene 253, 237–247.[CrossRef][ISI][Medline]
Kim HJ, Triplett BA. 2001. Cotton fibre growth in planta and in vitro. Models for plant cell elongation and cell wall biogenesis. Plant Physiology 127, 1361–1366.
Koncz C, Schell J. 1986. The promoter of TL-DNA gene 5 controls the tissue-specific expression of chimaeric genes carried by a novel type of Agrobacterium binary vector. Molecular and General Genetics 204, 383–396.[CrossRef]
Krings U, Berger RG. 1998. Biotechnological production of flavours and fragrances. Applied Microbiology and Biotechnology 49, 1–8.[CrossRef][ISI][Medline]
Le Hir H, Nott A, Moore MJ. 2003. How introns influence and enhance eukaryotic gene expression. Trends in Biochemical Sciences 28, 215–220.[CrossRef][ISI][Medline]
León J, Rojo E, Titarenko E, Sanchez-Serrano JJ. 1998. Jasmonic acid-dependent and -independent wound signal transduction pathways are differentially regulated by Ca2+/calmodulin in Arabidopsis thaliana. Molecular and General Genetics 258, 412–419.
Li S, Yi Y, Wang Y, Zhang Z, Beasley RS. 2002. Camptothecin accumulation and variation in Camptotheca. Planta Medica 68, 1010–1016.[CrossRef][ISI][Medline]
Liu H-C, Creech R-G, Jenkins JN, Ma D-P. 2000. Cloning and promoter analysis of the cotton lipid transfer protein gene Ltp3. Biochimica et Biophysica Acta 1487, 106–111.[Medline]
Mahlberg PG, Kim ES. 1992. Secretory vesicle formation in glandular trichomes of Cannabis sativa (Cannabaceae). American Journal of Botany 79, 166–173.[CrossRef]
Maas C, Laufs J, Grant S, Korfhage C, Werr W. 1991. The combination of a novel stimulatory element in the first exon of the maize Shrunken-1 gene with the following intron 1 enhances reporter gene expression up to 1000-fold. Plant Molecular Biology 16, 199–207.[CrossRef][ISI][Medline]
Morello L, Bardini M, Sala F, Breviario D. 2002. A long leader intron of the Ostub16 rice ß-tubulin gene is required for high-level gene expression and can autonomously promote transcription both in vivo and in vitro. The Plant Journal 29, 33–44.[CrossRef][ISI][Medline]
Oppenheimer DG, Herman PL, Esch J, Sivakumaran S, Marks MD. 1991. A myb-related gene required for leaf trichome differentiation in Arabidopsis is expressed in stipules. Cell 67, 483–493.[CrossRef][ISI][Medline]
Plesse B, Criqui M-C, Durr A, Parmentier Y, Fleck J, Genschik P. 2001. Effects of the polyubiquitin gene Ubi.U4 leader intron and first ubiquitin monomer on reporter gene expression in Nicotiana tabacum. Plant Molecular Biology 45, 655–667.[CrossRef][ISI][Medline]
Wagner GJ, Wang E, Shepherd RW. 2004. New approaches for studying and exploiting an old protuberances, the plant trichome. Annals of Botany 93, 3–11.
Wang E, Gan S, Wagner GJ. 2002. Isolation and characterization of the CYP71D16 trichome-specific promoter from Nicotiana tabacum L. Journal of Experimental Botany 53, 1891–1897.
Wang E, Hall JT, Wagner GJ. 2004a. Transgenic Nicotiana tabacum L. with enhanced trichome exudates cembratrieneols has reduced aphid infection in the field. Molecular Breeding 13, 49–57.
Wang S, Wang J-W, Yu N, Li C-H, Gou J-Y, Wang L-J, Chen X-Y. 2004b. Control of plant trichome development by a cotton fibre MYB gene. The Plant Cell 16, 2323–2334.
Werker E. 2000. Trichome diversity and development. In: Hallahan DL, Gray JC, eds. Advances in botanical research, Vol. 31. San Diego: Academic Press, 37–75.
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