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1.  CRY1a influences the diurnal transcription of photoreceptor genes in tomato plants after gibberellin treatment 
Plant Signaling & Behavior  2012;7(8):1034-1036.
Light is one of the most important environmental signal for plants. Involvement of hormones, such as gibberellic acid, in light regulated development has been known for many years, though the molecular mechanisms remain still largely unknown. To shed light on possible interactions between phyto-hormones and photoperceptive photoreceptors of tomato, in a recent work we investigated the molecular effects of exogenous gibberellin to cryptochrome and phytochrome transcripts in wild type tomato as well as in a mutant genotype with a non-functional cryptochrome 1a and in a transgenic line overexpressing cryptochrome 2. Results highlight that following addition of gibberellin, cryptochrome and phytochrome transcription patterns are strongly modified, especially in cryptochrome 1a deficient plants. Our results suggest that cryptochrome mediated light responses can be modulated by gibberellin accumulation level, in tomato plants.
PMCID: PMC3474674  PMID: 22827952
cryptochromes; gibberellin; light; phytochromes; tomato
2.  Proteome Regulation during Olea europaea Fruit Development 
PLoS ONE  2013;8(1):e53563.
Widespread in the Mediterranean basin, Olea europaea trees are gaining worldwide popularity for the nutritional and cancer-protective properties of the oil, mechanically extracted from ripe fruits. Fruit development is a physiological process with remarkable impact on the modulation of the biosynthesis of compounds affecting the quality of the drupes as well as the final composition of the olive oil. Proteomics offers the possibility to dig deeper into the major changes during fruit development, including the important phase of ripening, and to classify temporal patterns of protein accumulation occurring during these complex physiological processes.
Methodology/Principal Findings
In this work, we started monitoring the proteome variations associated with olive fruit development by using comparative proteomics coupled to mass spectrometry. Proteins extracted from drupes at three different developmental stages were separated on 2-DE and subjected to image analysis. 247 protein spots were revealed as differentially accumulated. Proteins were identified from a total of 121 spots and discussed in relation to olive drupe metabolic changes occurring during fruit development. In order to evaluate if changes observed at the protein level were consistent with changes of mRNAs, proteomic data produced in the present work were compared with transcriptomic data elaborated during previous studies.
This study identifies a number of proteins responsible for quality traits of cv. Coratina, with particular regard to proteins associated to the metabolism of fatty acids, phenolic and aroma compounds. Proteins involved in fruit photosynthesis have been also identified and their pivotal contribution in oleogenesis has been discussed. To date, this study represents the first characterization of the olive fruit proteome during development, providing new insights into fruit metabolism and oil accumulation process.
PMCID: PMC3547947  PMID: 23349718
3.  Olive phenolic compounds: metabolic and transcriptional profiling during fruit development 
BMC Plant Biology  2012;12:162.
Olive (Olea europaea L.) fruits contain numerous secondary metabolites, primarily phenolics, terpenes and sterols, some of which are particularly interesting for their nutraceutical properties. This study will attempt to provide further insight into the profile of olive phenolic compounds during fruit development and to identify the major genetic determinants of phenolic metabolism.
The concentration of the major phenolic compounds, such as oleuropein, demethyloleuropein, 3–4 DHPEA-EDA, ligstroside, tyrosol, hydroxytyrosol, verbascoside and lignans, were measured in the developing fruits of 12 olive cultivars. The content of these compounds varied significantly among the cultivars and decreased during fruit development and maturation, with some compounds showing specificity for certain cultivars. Thirty-five olive transcripts homologous to genes involved in the pathways of the main secondary metabolites were identified from the massive sequencing data of the olive fruit transcriptome or from cDNA-AFLP analysis. Their mRNA levels were determined using RT-qPCR analysis on fruits of high- and low-phenolic varieties (Coratina and Dolce d’Andria, respectively) during three different fruit developmental stages. A strong correlation was observed between phenolic compound concentrations and transcripts putatively involved in their biosynthesis, suggesting a transcriptional regulation of the corresponding pathways. OeDXS, OeGES, OeGE10H and OeADH, encoding putative 1-deoxy-D-xylulose-5-P synthase, geraniol synthase, geraniol 10-hydroxylase and arogenate dehydrogenase, respectively, were almost exclusively present at 45 days after flowering (DAF), suggesting that these compounds might play a key role in regulating secoiridoid accumulation during fruit development.
Metabolic and transcriptional profiling led to the identification of some major players putatively involved in biosynthesis of secondary compounds in the olive tree. Our data represent the first step towards the functional characterisation of important genes for the determination of olive fruit quality.
PMCID: PMC3480905  PMID: 22963618
Olea europaea; Phenolics; Secoiridoids; RT-qPCR; Transcriptome; Secondary metabolism
4.  Gibberellin and Auxin Influence the Diurnal Transcription Pattern of Photoreceptor Genes via CRY1a in Tomato 
PLoS ONE  2012;7(1):e30121.
Plant photoreceptors, phytochromes and cryptochromes, regulate many aspects of development and growth, such as seed germination, stem elongation, seedling de-etiolation, cotyledon opening, flower induction and circadian rhythms. There are several pieces of evidence of interaction between photoreceptors and phyto-hormones in all of these physiological processes, but little is known about molecular and genetic mechanisms underlying hormone-photoreceptor crosstalk.
Methodology/Principal Findings
In this work, we investigated the molecular effects of exogenous phyto-hormones to photoreceptor gene transcripts of tomato wt, as well as transgenic and mutant lines with altered cryptochromes, by monitoring day/night transcript oscillations. GA and auxin alter the diurnal expression level of different photoreceptor genes in tomato, especially in mutants that lack a working form of cryptochrome 1a: in those mutants the expression of some (IAA) or most (GA) photoreceptor genes is down regulated by these hormones.
Our results highlight the presence of molecular relationships among cryptochrome 1a protein, hormones, and photoreceptors' gene expression in tomato, suggesting that manipulation of cryptochromes could represent a good strategy to understand in greater depth the role of phyto-hormones in the plant photoperceptive mechanism.
PMCID: PMC3260215  PMID: 22272283
5.  First Survey of the Wheat Chromosome 5A Composition through a Next Generation Sequencing Approach 
PLoS ONE  2011;6(10):e26421.
Wheat is one of the world's most important crops and is characterized by a large polyploid genome. One way to reduce genome complexity is to isolate single chromosomes using flow cytometry. Low coverage DNA sequencing can provide a snapshot of individual chromosomes, allowing a fast characterization of their main features and comparison with other genomes. We used massively parallel 454 pyrosequencing to obtain a 2x coverage of wheat chromosome 5A. The resulting sequence assembly was used to identify TEs, genes and miRNAs, as well as to infer a virtual gene order based on the synteny with other grass genomes. Repetitive elements account for more than 75% of the genome. Gene content was estimated considering non-redundant reads showing at least one match to ESTs or proteins. The results indicate that the coding fraction represents 1.08% and 1.3% of the short and long arm respectively, projecting the number of genes of the whole chromosome to approximately 5,000. 195 candidate miRNA precursors belonging to 16 miRNA families were identified. The 5A genes were used to search for syntenic relationships between grass genomes. The short arm is closely related to Brachypodium chromosome 4, sorghum chromosome 8 and rice chromosome 12; the long arm to regions of Brachypodium chromosomes 4 and 1, sorghum chromosomes 1 and 2 and rice chromosomes 9 and 3. From these similarities it was possible to infer the virtual gene order of 392 (5AS) and 1,480 (5AL) genes of chromosome 5A, which was compared to, and found to be largely congruent with the available physical map of this chromosome.
PMCID: PMC3196578  PMID: 22028874
6.  Comparative 454 pyrosequencing of transcripts from two olive genotypes during fruit development 
BMC Genomics  2009;10:399.
Despite its primary economic importance, genomic information on olive tree is still lacking. 454 pyrosequencing was used to enrich the very few sequence data currently available for the Olea europaea species and to identify genes involved in expression of fruit quality traits.
Fruits of Coratina, a widely cultivated variety characterized by a very high phenolic content, and Tendellone, an oleuropein-lacking natural variant, were used as starting material for monitoring the transcriptome. Four different cDNA libraries were sequenced, respectively at the beginning and at the end of drupe development. A total of 261,485 reads were obtained, for an output of about 58 Mb. Raw sequence data were processed using a four step pipeline procedure and data were stored in a relational database with a web interface.
Massively parallel sequencing of different fruit cDNA collections has provided large scale information about the structure and putative function of gene transcripts accumulated during fruit development. Comparative transcript profiling allowed the identification of differentially expressed genes with potential relevance in regulating the fruit metabolism and phenolic content during ripening.
PMCID: PMC2748093  PMID: 19709400
7.  Diurnal and Circadian Rhythms in the Tomato Transcriptome and Their Modulation by Cryptochrome Photoreceptors 
PLoS ONE  2008;3(7):e2798.
Circadian clocks are internal molecular time-keeping mechanisms that provide living organisms with the ability to adjust their growth and physiology and to anticipate diurnal environmental changes. Circadian clocks, without exception, respond to light and, in plants, light is the most potent and best characterized entraining stimulus. The capacity of plants to respond to light is achieved through a number of photo-perceptive proteins including cryptochromes and phytochromes. There is considerable experimental evidence demonstrating the roles of photoreceptors in providing light input to the clock.
In order to identify genes regulated by diurnal and circadian rhythms, and to establish possible functional relations between photoreceptors and the circadian clock in tomato, we monitored the temporal transcription pattern in plants entrained to long-day conditions, either by large scale comparative profiling, or using a focused approach over a number of photosensory and clock-related genes by QRT-PCR. In parallel, focused transcription analyses were performed in cry1a- and in CRY2-OX tomato genotypes.
We report a large series of transcript oscillations that shed light on the complex network of interactions among tomato photoreceptors and clock-related genes. Alteration of cryptochrome gene expression induced major changes in the rhythmic oscillations of several other gene transcripts. In particular, over-expression of CRY2 had an impact not only on day/night fluctuations but also on rhythmicity under constant light conditions. Evidence was found for widespread diurnal oscillations of transcripts encoding specific enzyme classes (e.g. carotenoid biosynthesis enzymes) as well as for post-transcriptional diurnal and circadian regulation of the CRY2 transcript.
PMCID: PMC2474677  PMID: 18665253

Results 1-7 (7)