M. Zanor | National Council of Scientific and Technological Research (CONICET) (original) (raw)

Papers by M. Zanor

Metabolomics, 2015

Elucidating the determinants of tomato nutritional value and fruit quality to introduce improved ... more Elucidating the determinants of tomato nutritional value and fruit quality to introduce improved varieties on the international market represents a major challenge for crop biotechnology. Different strategies can be undertaken to exploit the natural variability of Solanum to re-incorporate lost allelic diversity into commercial varieties. One of them is the characterization of selected germplasm for breeding programs. To achieve this goal, 18 RILs (S. lycopersicum x S. pimpinellifolium) were comprehensively phenotyped for fruit polar metabolites and quality associated traits. Metabolites were quantified by GC-MS and 1 H-NMR. Integrative analyses by neuronal clustering and network construction revealed that fruit properties are strongly associated with the metabolites aspartate, serine, glutamate and 2-oxoglutarate. Shelf life and firmness appeared to be linked to malate content. By a comparative analysis of the whole data set, ten RILs presented higher number of traits with positive effect than the S. lycopersicum x S. pimpinellifolium hybrid. Thus, these lines can be proposed as promising candidates for breeding programs aimed to improve fruit quality.

The Plant Journal, 2008

SummaryIn contrast to animal growth, plant growth is largely post‐embryonic. Therefore plants hav... more SummaryIn contrast to animal growth, plant growth is largely post‐embryonic. Therefore plants have developed new mechanisms to precisely regulate cell proliferation by means of internal and external stimuli whilst the general core cell cycle machinery is conserved between eukaryotes. In this work we demonstrate a role for the Arabidopsis thaliana DNA‐binding‐with‐one‐finger (DOF) transcription factor OBP1 in the control of cell division upon developmental signalling. Inducible overexpression of OBP1 resulted in a significant overrepresentation of cell cycle genes among the upregulated transcripts. Direct targets of OBP1, as verified by chromatin immunoprecipitation, include at least the core cell cycle gene CYCD3;3 and the replication‐specific transcription factor gene AtDOF2;3. Consistent with our molecular data, short‐term activation of OBP1 in cell cultures affected cell cycle re‐entry, shortening the duration of the G1 phase and the overall length of the cell cycle, whilst const...

The Plant Journal, 2006

SummaryGlucosinolates are a group of secondary metabolites that function as defense substances ag... more SummaryGlucosinolates are a group of secondary metabolites that function as defense substances against herbivores and micro‐organisms in the plant order Capparales. Indole glucosinolates (IGS), derivatives of tryptophan, may also influence plant growth and development. In Arabidopsis thaliana, indole‐3‐acetaldoxime (IAOx) produced from tryptophan by the activity of two cytochrome P450 enzymes, CYP79B2 and CYP79B3, serves as a precursor for IGS biosynthesis but is also an intermediate in the biosynthetic pathway of indole‐3‐acetic acid (IAA). Another cytochrome P450 enzyme, CYP83B1, funnels IAOx into IGS. Although there is increasing information about the genes involved in this biochemical pathway, their regulation is not fully understood. OBP2 has recently been identified as a member of the DNA‐binding‐with‐one‐finger (DOF) transcription factors, but its function has not been studied in detail so far. Here we report that OBP2 is expressed in the vasculature of all Arabidopsis organs...

Plant Physiology, 2006

New Phytologist, 2007

In a phenotypic screen of plants constitutively overexpressing DOF (DNA-binding-with-one-finger) ... more In a phenotypic screen of plants constitutively overexpressing DOF (DNA-binding-with-one-finger) transcription factors under the control of the Cauliflower mosaic virus 35S promoter, AtDOF4;2 was identified as a gene inducing a bushy plant phenotype and potentially being involved in the regulation of phenylpropanoid metabolism in Arabidopsis. Further molecular and biochemical characterization was performed in parallel using transgenic plants with enhanced and reduced AtDOF4;2 expression. The expression pattern of AtDOF4;2 was determined by quantitative real-time polymerase chain reaction (Q-RTPCR) and through promoter-beta-glucuronidase (GUS) fusions, indicating preferential transcriptional activity in axillary buds of the flower stalk, the hypocotyls periderm and in tapetum cells. Constitutive overexpression and RNAi-mediated silencing of AtDOF4;2 caused reciprocal changes in the expression of flavonoid biosynthetic genes and the accumulation of flavonoids under cold and high-light conditions. Moreover, tapetum-specific overexpression of AtDOF4;2 led to pollen grains devoid of flavonols. In contrast to its negative influence on flavonoid biosynthesis and coincident with high expression in the periderm and tapetum, AtDOF4;2 positively influences the production of hydroxycinnamic acids in the hypocotyl and flower buds, implicating its possible importance for suberin and sporopollenin production. These data provide evidence that AtDOF4;2, influences phenylpropanoid metabolism in an environmental and tissue-specific manner.

Protein array technology has emerged as a new tool to enable ordered screening of proteins for ex... more Protein array technology has emerged as a new tool to enable ordered screening of proteins for expression and molecular interactions in high throughput. Besides classical solid-phase substrates, such as micro-titre plates and membrane filters, protein arrays have recently been devised with chip-sized supports. Several applications on protein chips have been described, but to our knowledge no studies using plant protein chips were published so far. The aim of this study was to generate Arabidopsis protein chips and to demonstrate the feasibility of the protein chip technology for the investigation of antigen-antibody interactions. Therefore, Arabidopsis cDNAs encoding 95 different proteins were cloned into a GATEWAY-compatible Escherichia coli expression vector. RGS-His6-tagged recombinant proteins were purified in high throughput and robotically arrayed onto glass slides coated either with a nitrocellulose based polymer (FAST slides) or polyacrylamide (PAA slides). Using an anti-RGS...

Plant Molecular Biology, 2005

Despite the central importance of the TCA cycle in plant metabolism not all of the genes encoding... more Despite the central importance of the TCA cycle in plant metabolism not all of the genes encoding its constituent enzymes have been functionally identified. In yeast, the heterodimeric protein succinyl CoA ligase is encoded for by two single-copy genes. Here we report the isolation of two tomato cDNAs coding for a-and one coding for the b-subunit of succinyl CoA ligase. These three cDNAs were used to complement the respective Saccharomyces cerevisiae mutants deficient in the a-and b-subunit, demonstrating that they encode functionally active polypeptides. The genes encoding for the subunits were expressed in all tissues, but most strongly in floral and leaf tissues, with equivalent expression of the two a-subunit genes being expressed to equivalent levels in all tissues. In all instances GFP fusion expression studies confirmed an expected mitochondrial location of the proteins encoded. Following the development of a novel assay to measure succinyl CoA ligase activity, in the direction of succinate formation, the evaluation of the maximal catalytic activities of the enzyme in a range of tissues revealed that these paralleled those of mRNA levels. We also utilized this assay to perform a preliminary characterisation of the regulatory properties of the enzyme suggesting allosteric control of this enzyme which may regulate flux through the TCA cycle in a manner consistent with its position therein.

Journal of Experimental Botany, 2009

A beta-1,3-glucanase gene from Hordeum vulgare was isolated by a PCR strategy, cloned and subsequ... more A beta-1,3-glucanase gene from Hordeum vulgare was isolated by a PCR strategy, cloned and subsequently sequenced. The amplified sequence contained the entire coding region of the isoenzyme II, which is interrupted by a 165 bp intron at 73 bp downstream the starting codon. This intron contains all the elements required for the processing mechanism in monocots: a high A + U content, the appropriate splice sites in the 5' and 3' ends and four typical YUNAN consensus sequences. Transient transformation of wheat protoplasts with the complete beta-1,3-glucanase gene under the control of maize polyubiquitin promoter revealed that the intron sequence was spliced out. The gene was also expressed at high levels, probably due to an enhancer-like sequence found near the 3' end of the intron.

DNA sequence : the journal of DNA sequencing and mapping, 2000

Plant molecular biology, 2003

THE PLANT CELL ONLINE, 2012

The transition from juvenility through maturation to senescence is a complex process that involve... more The transition from juvenility through maturation to senescence is a complex process that involves the regulation of longevity. Here, we identify JUNGBRUNNEN1 (JUB1), a hydrogen peroxide (H 2 O 2 )-induced NAC transcription factor, as a central longevity regulator in Arabidopsis thaliana. JUB1 overexpression strongly delays senescence, dampens intracellular H 2 O 2 levels, and enhances tolerance to various abiotic stresses, whereas in jub1-1 knockdown plants, precocious senescence and lowered abiotic stress tolerance are observed. A JUB1 binding site containing a RRYGCCGT core sequence is present in the promoter of DREB2A, which plays an important role in abiotic stress responses. JUB1 transactivates DREB2A expression in mesophyll cell protoplasts and transgenic plants and binds directly to the DREB2A promoter. Transcriptome profiling of JUB1 overexpressors revealed elevated expression of several reactive oxygen species-responsive genes, including heat shock protein and glutathione S-transferase genes, whose expression is further induced by H 2 O 2 treatment. Metabolite profiling identified elevated Pro and trehalose levels in JUB1 overexpressors, in accordance with their enhanced abiotic stress tolerance. We suggest that JUB1 constitutes a central regulator of a finely tuned control system that modulates cellular H 2 O 2 level and primes the plants for upcoming stress through a gene regulatory network that involves DREB2A.

PLANT PHYSIOLOGY, 2006

Despite much study of the role of S-adenosylmethionine (SAM) in the methylation of DNA, RNA, and ... more Despite much study of the role of S-adenosylmethionine (SAM) in the methylation of DNA, RNA, and proteins, and as a cofactor for a wide range of biosynthetic processes, little is known concerning the intracellular transport of this essential metabolite. Screening of the Arabidopsis (Arabidopsis thaliana) genome yielded two potential homologs of yeast (Saccharomyces cerevisiae) and human SAM transporters, designated as SAMC1 and SAMC2, both of which belong to the mitochondrial carrier protein family. The SAMC1 gene is broadly expressed at the organ level, although only in specialized tissues of roots with high rates of cell division, and appears to be up-regulated in response to wounding stress, whereas the SAMC2 gene is very poorly expressed in all organs/tissues analyzed. Direct transport assays with the recombinant and reconstituted SAMC1 were utilized to demonstrate that this protein displays a very narrow substrate specificity confined to SAM and its closest analogs. Further experiments revealed that SAMC1 was able to function in uniport and exchange reactions and characterized the transporter as highly active, but sensitive to physiologically relevant concentrations of S-adenosylhomocysteine, S-adenosylcysteine, and adenosylornithine. Green fluorescent protein-based cell biological analysis demonstrated targeting of SAMC1 to mitochondria. Previous proteomic analyses identified this protein also in the chloroplast inner envelope. In keeping with these results, bioinformatics predicted dual localization for SAMC1. These findings suggest that the provision of cytosolically synthesized SAM to mitochondria and possibly also to plastids is mediated by SAMC1 according to the relative demands for this metabolite in the organelles.

PLANT PHYSIOLOGY, 2009

It has been previously demonstrated, utilizing intraspecific introgression lines, that Lycopersic... more It has been previously demonstrated, utilizing intraspecific introgression lines, that Lycopersicum Invertase5 (LIN5), which encodes a cell wall invertase, controls total soluble solids content in tomato (Solanum lycopersicum). The physiological role of this protein, however, has not yet been directly studied, since evaluation of data obtained from the introgression lines is complicated by the fact that they additionally harbor many other wild species alleles. To allow a more precise comparison, we generated transgenic tomato in which we silenced the expression of LIN5 using the RNA interference approach. The transformants were characterized by an altered flower and fruit morphology, displaying increased numbers of petals and sepals per flower, an increased rate of fruit abortion, and a reduction in fruit size. Evaluation of the mature fruit revealed that the transformants were characterized by a reduction of seed number per plant. Furthermore, detailed physiological analysis revealed that the transformants displayed aberrant pollen morphology and a reduction in the rate of pollen tube elongation. Metabolite profiling of ovaries and green and red fruit revealed that metabolic changes in the transformants were largely confined to sugar metabolism, whereas transcript and hormone profiling revealed broad changes both in the hormones themselves and in transcripts encoding their biosynthetic enzymes and response elements. These results are discussed in the context of current understanding of the role of sugar during the development of tomato fruit, with particular focus given to its impact on hormone levels and organ morphology.