Salomé Prat | Universidad Autónoma de Madrid (original) (raw)

Papers by Salomé Prat

Cell elongation during seedling development is antagonistically regulated by light and gibberelli... more Cell elongation during seedling development is antagonistically regulated by light and gibberellins (GAs) 1,2 . Light induces photomorphogenesis, leading to inhibition of hypocotyl growth, whereas GAs promote etiolated growth, characterized by increased hypocotyl elongation. The mechanism underlying this antagonistic interaction remains unclear. Here we report on the central role of the Arabidopsis thaliana nuclear transcription factor PIF4 (encoded by PHYTOCHROME INTERACTING FACTOR 4) 3 in the positive control of genes mediating cell elongation and show that this factor is negatively regulated by the light photoreceptor phyB (ref. 4) and by DELLA proteins that have a key repressor function in GA signalling 5 . Our results demonstrate that PIF4 is destabilized by phyB in the light and that DELLAs block PIF4 transcriptional activity by binding the DNA-recognition domain of this factor. We show that GAs abrogate such repression by promoting DELLA destabilization, and therefore cause a concomitant accumulation of free PIF4 in the nucleus. Consistent with this model, intermediate hypocotyl lengths were observed in transgenic plants over-accumulating both DELLAs and PIF4. Destabilization of this factor by phyB, together with its inactivation by DELLAs, constitutes a protein interaction framework that explains how plants integrate both light and GA signals to optimize growth and development in response to changing environments.

Article Title: Genes driving potato tuber initiation and growth: identification based on transcri... more Article Title: Genes driving potato tuber initiation and growth: identification based on transcriptional changes using the POCI array Year of publication: 2008 Link to published version:http://dx.

Transgenic research, 2003

The increasing presence of transgenic plant derivatives in a wide range of animal and human consu... more The increasing presence of transgenic plant derivatives in a wide range of animal and human consumables has provoked in western Europe a strong demand for appropriate detection methods to evaluate the existence of transgenic elements. Among the different techniques currently used, the real-time quantitative PCR is a powerful technology well adapted to the mandatory labeling requirements in the European Union (EU). The use of transgene flanking genomic sequences has recently been suggested as a means to avoid ambiguous results both in qualitative and quantitative PCR-based technologies. In this study we report the identification of genomic sequences adjacent to the 3'-integration site of event MON810 in transgenic maize. This genetically modified crop contains transgene sequences leading to ectopic expression of a synthetic CryIA(b) endotoxin which confers resistance to lepidopteran insects especially against the European corn borer. The characterization of the genome-transgene j...

Current Opinion in Genetics & Development, 2008

The Plant Journal, 2012

Arabidopsis seedlings display rhythmic growth when grown under diurnal conditions, with maximal e... more Arabidopsis seedlings display rhythmic growth when grown under diurnal conditions, with maximal elongation rates occurring at the end of the night under short-day photoperiods. Current evidence indicates that this behavior involves the action of the growth-promoting bHLH factors PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) and PHYTOCHROME-INTERACTING FACTOR 5 (PIF5) at the end of the night, through a coincidence mechanism that combines their transcriptional regulation by the circadian clock with control of protein accumulation by light. To assess the possible role of PIF3 in this process, we have analyzed hypocotyl responses and marker gene expression in pif single-and higher-order mutants. The data show that PIF3 plays a prominent role as a promoter of seedling growth under diurnal light/dark conditions, in conjunction with PIF4 and PIF5. In addition, we provide evidence that PIF3 functions in this process through its intrinsic transcriptional regulatory activity, at least in part by directly targeting growth-related genes, and independently of its ability to regulate phytochrome B (phyB) levels. Furthermore, in sharp contrast to PIF4 and PIF5, our data show that the PIF3 gene is not subject to transcriptional regulation by the clock, but that PIF3 protein abundance oscillates under diurnal conditions as a result of a progressive decline in PIF3 protein degradation mediated by photoactivated phyB, and consequent accumulation of the bHLH factor during the dark period. Collectively, the data suggest that phyB-mediated, post-translational regulation allows PIF3 accumulation to peak just before dawn, at which time it accelerates hypocotyl growth, together with PIF4 and PIF5, by directly regulating the induction of growth-related genes.

The Plant Journal, 2000

Gene StGA20ox1 encoding potato GA 20-oxidase is expressed to relatively high levels in leaves and... more Gene StGA20ox1 encoding potato GA 20-oxidase is expressed to relatively high levels in leaves and regulated by daylength. To investigate whether this gene is involved in photoperiodic regulation of tuber formation, we have obtained transgenic potato plants expressing sense and antisense copies of the StGA20ox1 cDNA. Over-expression of this cDNA resulted in taller plants that required a longer duration of a short day photoperiod (SD) to tuberize. Tubers from these plants had a decreased time of dormancy and developed sprouts with elongated internodes. Plants expressing antisense copies of the StGA20ox1 cDNA had shorter stems, a decreased length of the internodes and tuberized earlier than control plants, showing increased tuber yields. Antisense inhibition of this gene had no visible effect on the time of dormancy of the tubers, although at the end of dormancy these formed sprouts with shortened internodes. Decreased levels of endogenous GA 20 and GA 1 were detected in the apex and ®rst leaves of the antisense lines. These results demonstrate the involvement of the GA 20-oxidase activity encoded by StGA20ox1 in the control of stem elongation and in tuber induction but not in tuber dormancy, indicating that the latter may be regulated by another member of the gene family.

The Plant Journal, 1999

Comparative analysis by differential RNA display (DDRT± PCR) of the expression patterns of potato... more Comparative analysis by differential RNA display (DDRT± PCR) of the expression patterns of potato plants induced and non-induced to tuberize, led to the isolation of a cDNA clone, C40.4, that is strongly upregulated in the leaves of tuberizing plants. Leaf expression of this transcript was shown to be light-dependent, with increased levels of mRNA and protein being detected during the light hours. Sequence analysis revealed near complete identity to potato CDSP34, a thylakoid protein induced by drought stress, and strong homology to the carotenoid-associated proteins ®brillin, ChrB and PAP from pepper fruit, and CHRC from cucumber¯owers. By using an antibody against pepper ®brillin, we were able to demonstrate a chloroplastic location of the C40.4 protein in association with the thylakoid membranes. Two-dimensional analysis of thylakoid pigment±protein complexes showed a speci®c association of the protein with the photosystem II (PSII) multi-subunit complex. Antisense plants with reduced levels of accumulation of C40.4 showed a stunted growth and decreased tuber yield and exhibited reduced values of non-photochemical quenching of chlorophyll a¯uorescence. Altogether, these results indicate a preferential association of the C40.4 protein with the light harvesting complex of photosystem II (LHCII) antenna pigment complexes, and suggest a functional role of this protein in photosynthesis, by modulating photosynthetic ef®ciency and dissipation of excess absorbed light energy within the antenna complex.

by David Alabadi, Federico Valverde, Salomé Prat, Raquel Martín, Crisanto Gutierrez, Montserrat Pagès, Berta Sotillo, Eugenio Minguet, Julio Muñoz, Jose Pardo, and Sanna Olsson

The Plant Journal, 2014

Proceedings of the National Academy of Sciences, 1990

Potato nuclear proteins specifically bind to a DNA sequence at the most 5' distal region of the p... more Potato nuclear proteins specifically bind to a DNA sequence at the most 5' distal region of the promoter of a potato proteinase inhibitor H gene. Binding studies using the electrophoretic mobility-shift assay showed the appearance of two protein-DNA complexes in the presence of both tuber and leaf nuclear protein extracts. Mechanical wounding of the leaves had no effect on the amount of specific protein-DNA complexes formed. DNase I protection analysis and binding to synthetic oligonucleotides identified the sequence 5'-GAGGGT-ATTTTCGTAA-3' as the target for the noncooperative binding of two potato nuclear proteins to the upstream element.

Proceedings of the National Academy of Sciences, 1989

Plants respond to wounding or pathogen attack by a variety of biochemical reactions, involving in... more Plants respond to wounding or pathogen attack by a variety of biochemical reactions, involving in some instances gene activation in tissues far apart from the actual site of wounding or pathogen invasion. One of the best analyzed examples for such a systemic reaction is the wound-induced expression of proteinase inhibitor genes in tomato and potato leaves. Local wounding of potato or tomato plants results in the accumulation of proteinase inhibitors I and II throughout the aerial part of the plant. In contrast to wild-type plants, abscisic acid-deficient mutants of potato (droopy) and tomato (sit) show a drastically reduced induction of these genes in response to plant wounding. High levels of proteinase inhibitor II gene expression are obtained in mutant and wild-type plants upon exogenous application of abscisic acid. Measurements of the endogenous abscisic acid levels in wild-type plants show that wounding results in increased levels of this phytohormone in wounded and nonwounded systemically induced leaves. Thus these results show that the plant hormone abscisic acid is involved in the wound-induced activation of the proteinase inhibitor II gene. Furthermore, -they are compatible with a model assuming this hormone to be the actual mediator of the systemic wound response.

PLoS ONE, 2011

Some potato species require a short-day (SD) photoperiod for tuberization, a process that is nega... more Some potato species require a short-day (SD) photoperiod for tuberization, a process that is negatively affected by gibberellins (GAs). Here we report the isolation of StGA3ox2, a gene encoding a GA 3-oxidase, whose expression is increased in the aerial parts and is repressed in the stolons after transfer of photoperiod-dependent potato plants to SD conditions. Over-expression of StGA3ox2 under control of constitutive or leaf-specific promoters results in taller plants which, in contrast to StGA20ox1 over-expressers previously reported, tuberize earlier under SD conditions than the controls. By contrast, StGA3ox2 tuber-specific over-expression results in non-elongated plants with slightly delayed tuber induction. Together, our experiments support that StGA3ox2 expression and gibberellin metabolism significantly contribute to the tuberization time in strictly photoperiod-dependent potato plants.

Nucleic Acids Research, 1985

The cDNA coding for a glutelin-2 protein from maize endosperm has been cloned and the complete am... more The cDNA coding for a glutelin-2 protein from maize endosperm has been cloned and the complete amino acid sequence of the protein derived for the first time. An immature maize endosperm cDNA bank was screened for the expression of a beta-lactamase:glutelin-2 (G2) fusion polypeptide by using antibodies against the purified 28 kd G2 protein. A clone corresponding to the 28 kd G2 protein was sequenced and the primary structure of this protein was derived. Five regions can be defined in the protein sequence: an 11 residue N-terminal part, a repeated region formed by eight units of the sequence Pro-Pro-Pro-Val-His-Leu, an alternating Pro-X stretch 21 residues long, a Cys rich domain and a C-terminal part rich in Gln. The protein sequence is preceded by 19 residues which have the characteristics of the signal peptide found in secreted proteins. Unlike zeins, the main maize storage proteins, 28 kd glutelin-2 has several homologous sequences in common with other cereal storage proteins.

Nature, 2008

MGG Molecular & General Genetics, 1989

Proteins present in tobacco nuclear extracts bind to a truncated cauliflower mosaic virus (CaMV) ... more Proteins present in tobacco nuclear extracts bind to a truncated cauliflower mosaic virus (CaMV) 35S promoter fragment (from -90 to + 2 relative to the transcription start site) in a sequence specific manner. Gel mobility shift assays show the presence of two protein-DNA complexes that are not competed by a -47/+ 2 promoter fragment. DNAse I protection and DNA methylation interference reveal two protected sites in the slower migrating complex; both include the pentamer TGACG, separated by a stretch of eight nucleotides where G methylation does not prevent the binding of the proteins. The faster complex is the prevalent form at low protein concentrations. As the protein concentration increases a non-linear rise in the amount of the slower migrating complex relative to the faster one is seen suggesting that cooperative effects are involved in the binding to the second site.

MGG Molecular & General Genetics, 1990

The 5'-upstream region of the class I patatin gene B33 directs strong expression of the b... more The 5'-upstream region of the class I patatin gene B33 directs strong expression of the beta-glucuronidase (GUS) reporter gene in potato tubers and in leaves treated with sucrose. Cis-acting elements affecting specificity and level of expression were identified by deletion analysis in transgenic potato plants. A putative tuber-specific element is located downstream from position -195. Nuclear proteins present in leaf and tuber extracts bind specifically to a conserved AT rich motif within this region. A DNA fragment between -183 and -143, including the binding site is, however, not able to enhance the expression of a truncated 35S promoter from cauliflower mosaic virus. Independent positive elements contributing to a 100-fold increase relative to the basic tuber-specific element are located between -228 and -195; -736 and -509, -930 and -736 and -1512 and -951. Sucrose inducibility is controlled by sequences downstream of position -228, indicating that the tuber-specific and sucrose-inducible elements are in close proximity.

Journal of Plant Growth Regulation, 2001

Solanum tuberosum ssp. andigena plants require a short-day (SD) photoperiod for tuber formation, ... more Solanum tuberosum ssp. andigena plants require a short-day (SD) photoperiod for tuber formation, a process that is also affected by gibberellins (GAs). Grafting experiments have con®rmed that the photoperiod is perceived in the leaves. Tuber formation, however, usually takes place in the underground stolons. In this review, photoperioddependent tuberization has been divided into ®ve chronological events: SD photoperiod perception, short-term adaptive responses to SD conditions, generation and transport of tuber-inducing signal(s), tuber formation, and long-term adaptive responses to tuber growth. Within this frame of study, the interaction of GAs and photoperiod is revised. Similar to the¯owering process in Arabidopsis, we suggest the existence of two independent pathways that control tuber formation: a photoperiod-dependent pathway and a GA-dependent pathway. Nevertheless, photoperiod-dependent tuber formation requires the action of GAs at speci®c stages to orchestrate this complex process of development.

Journal of Agricultural and Food Chemistry, 2005

The number of cultured hectares and commercialized genetically modified organisms (GMOs) has incr... more The number of cultured hectares and commercialized genetically modified organisms (GMOs) has increased exponentially in the past 9 years. Governments in many countries have established a policy of labeling all food and feed containing or produced by GMOs. Consequently, versatile, laboratorytransferable GMO detection methods are in increasing demand. Here, we describe a qualitative PCRbased multiplex method for simultaneous detection and identification of four genetically modified maize lines: Bt11, MON810, T25, and GA21. The described system is based on the use of five primers directed to specific sequences in these insertion events. Primers were used in a single optimized multiplex PCR reaction, and sequences of the amplified fragments are reported. The assay allows amplification of the MON810 event from the 35S promoter to the hsp intron yielding a 468 bp amplicon. Amplification of the Bt11 and T25 events from the 35S promoter to the PAT gene yielded two different amplicons of 280 and 177 bp, respectively, whereas amplification of the 5′ flanking region of the GA21 gave rise to an amplicon of 72 bp. These fragments are clearly distinguishable in agarose gels and have been reproduced successfully in a different laboratory. Hence, the proposed method comprises a rapid, simple, reliable, and sensitive (down to 0.05%) PCR-based assay, suitable for detection of these four GM maize lines in a single reaction.

Gene, 1987

A collection of cDNA clones, corresponding to a group of maize endosperm proteins classified in t... more A collection of cDNA clones, corresponding to a group of maize endosperm proteins classified in the glutelin-2 (or reduced soluble proteins) and in the zein-2 subfractions, has been identified and characterized. The nucleotide sequence of three of these clones has been obtained and the amino acid sequence deduced. They appear to correspond to a small family of genes that are specifically expressed in immature endosperm simultaneously to zeins, the best characterized proteins from this tissue. Unlike zeins, the proteins of the glutelin-2 and zein-2 family contain sequences homologous to storage proteins from other cereals such as gliadins or hordeins. The cDNA clones encoding for the two types of proteins have been compared, and a high degree of homology has been observed for both the nucleotide and amino acid sequences. The differences existing in both the coding and non-coding regions allow the definition of multiple types of variability in their sequence. An hypothesis is proposed on how sequence diversity may have been generated in this particular class of plant proteins.

Hepatology, 1987

This work was supported in part by a grant from the Fondo de Investigaciones Sanitarias de la Seg... more This work was supported in part by a grant from the Fondo de Investigaciones Sanitarias de la Seguridad Social (86/1191), Ministerio de Educacidn y Ciencia, Spain. Addrees reprint requests to: J. Ceneeca, M.D., Department of Internal Medicine, Hospital General Val1 d'Hebron, Paseo Val1 d'Hebron s/n, Barcelona 08035, Spain. 16. Genesca J, Jardi R, Prat S, et al. Valor de la determinacion serica del DNA del virus de La hepatitis B como marcador de replicacion virica. Med Clin 1986,87:665-668. 17. Caredda F, Rossi E, Monforte AA, et al. Hepatitis B virus-associated coinfection and superinfection with delta agent: indistinguishable disease with different outcome. J Infect Dis 1985, 151:925-928. 18. Amoroso P, Giorgio A, Fico P, et al. Delta infection in the Naples area. Epidemiologic and clinical significance. J Hepatoll986 311-18.