Vincenzo Viscosi

The proteome of lentil (Lens culinaris Medik.) seeds: Discriminating between landraces

Lentil (Lens culinaris Medik.) is one of the most ancient crops of the Mediterranean region used for human nutrition; an extensive differentiation of L. culinaris over millennia has resulted in a number of different landraces. As a consequence of environmental and socio‐economic issues, the disappearance of many of them occurred in more recent times. To investigate the potential of proteomics as a tool in phylogenetic studies, testing the possibility to identify specific markers of different plant landraces, 2‐D gel electrophoretic maps of mature seeds were obtained from seven lentil populations belonging to a local ecotype (Capracotta) and five commercial varieties (Turca Rossa, Canadese, Castelluccio di Norcia, Rascino and Colfiorito). 2‐DE analysis resolved hundreds of protein species in each lentil sample, among which only 122 were further identified by MALDI‐TOF PMF and/or nanoLC‐ESI‐LIT‐MS/MS, probably as a result of the poor information available on L. culinaris genome. A comparison of these maps revealed that 103 protein spots were differentially expressed within and between populations. The multivariate statistical analyses carried out on these variably expressed spots showed that 24 protein species were essential for population discrimination, thus determining their proposition as landrace markers. Besides providing the first reference map of mature lentil seeds, our data confirm previous studies based on morphological/genetic observations and further support the valuable use of proteomic techniques as phylogenetic tool in plant studies.

Leaf morphological analyses in four European oak species (Quercus) and their hybrids: A comparison of traditional and geometric morphometric methods

Abstract In this study, leaf morphology was assessed in a mixed oak stand (western France) using two geometric morphometric (landmark and outline) datasets and one dataset of 19 leaf measures. Adult oaks (817 oaks), comprising four white oak species (Quercus petraea, Q. robur, Q. pubescens and Q. pyrenaica), were sampled for DNA extraction and genetic analysis (nuclear microsatellites). Leaf morphology was assessed on 336 oaks, comprising pure species and hybrids as determined by genetic assignment. This comparative study of oak leaf morphology, based on the use of two free size geometric morphometric methods and a set of leaf measurements, combined with the genetic assignment of individuals to pure species or hybrids, provided information about the differences among species and the intermediate leaf morphology of their hybrids.

Proteomic analysis of apricot fruit during ripening.

Ripening of climacteric fruits involves a complex network of biochemical and metabolic changes that make them palatable and rich in nutritional and health-beneficial compounds. Since fruit maturation has a profound impact on human nutrition, it has been recently the object of increasing research activity by holistic approaches, especially on model species. Here we report on the original proteomic characterization of ripening in apricot, a widely cultivated species of temperate zones appreciated for its taste and aromas, whose cultivation is yet hampered by specific limitations. Fruits of Prunus armeniaca cv. Vesuviana were harvested at three ripening stages and proteins extracted and resolved by 1D and 2D electrophoresis. Whole lanes from 1D gels were subjected to shot-gun analysis that identified 245 gene products, showing preliminary qualitative differences between maturation stages. In parallel, differential analysis of 2D proteomic maps highlighted 106 spots as differentially represented among variably ripen fruits. Most of these were further identified by means of MALDI-TOF-PMF and nanoLC-ESI-LIT-MS/MS as enzymes involved in main biochemical processes influencing metabolic/structural changes occurring during maturation, i.e. organic acids, carbohydrates and energy metabolism, ethylene biosynthesis, cell wall restructuring and stress response, or as protein species linkable to peculiar fruit organoleptic characteristics. In addition to originally present preliminary information on the main biochemical changes that characterize apricot ripening, this study also provides indications for future marker-assisted selection breeding programs aimed to ameliorate fruit quality.

Comparative leaf surface morphology and molecular data of five oaks of the subgenus Quercus Oerst (Fagaceae)

Abstract Comparisons between different data sets are important in taxonomic studies, particularly for complex taxa such as the genus Quercus. However, there is scarce literature on comparative morphological and molecular analyses in oaks. Here we describe an experimental approach based on the correlation between micromorphological features and molecular data in order to characterize and discriminate among five closely related species: Q. robur, Q. petraea, Q. frainetto, Q. pubescens and Q. virgiliana.

The proteome of Populus nigra woody root: response to bending

BACKGROUND AND AIMS Morphological and biomechanical alterations occurring in woody roots of many plant species in response to mechanical stresses are well documented; however, little is known about the molecular mechanisms regulating these important alterations. The first forest tree genome to be decoded is that of Populus, thereby providing a tool with which to investigate the mechanisms controlling adaptation of woody roots to changing environments. The aim of this study was to use a proteomic approach to investigate the response of Populus nigra woody taproot to mechanical stress. METHODS To simulate mechanical perturbations, the taproots of 30 one-year-old seedlings were bent to an angle of 90 ° using a steel net. A spatial and temporal two-dimensional proteome map of the taproot axis was obtained. We compared the events occurring in the above-bending, central bending and below-bending sectors of the taproot. KEY RESULTS The first poplar woody taproot proteome map is reported here; a total of 207 proteins were identified. Spatial and temporal proteomic analysis revealed that factors involved in plant defence, metabolism, reaction wood formation and lateral root development were differentially expressed in the various sectors of bent vs. control roots, seemingly in relation to the distribution of mechanical forces along the stressed woody taproots. A complex interplay among different signal transduction pathways involving reactive oxygen species appears to modulate these responses. CONCLUSIONS Poplar woody root uses different temporal and spatial mechanisms to respond to mechanical stress. Long-term bending treatment seem to reinforce the defence machinery, thereby enabling the taproot to better overcome winter and to be ready to resume growth earlier than controls.

Leaf Shape and Size Differentiation in White Oaks: Assessment of Allometric Relationships among Three Sympatric Species and Their Hybrids

A combined genetic and morphometric approach was used to study leaf shape and size variability among three sympatric and interfertile white oak species (Quercus frainetto, Quercus petraea, and Quercus pubescens) sampled in a mixed forest in central Italy. Leaf shape and size were analyzed separately to discriminate species, to identify unique leaf shape traits, and to analyze the relationships between hybrid phenotypes and their parental species. In addition, the covariation of leaf shape and size (i.e., allometry) was tested at the intraspecific level, and the differences in allometric trajectories were compared among species and hybrids. Finally, size correction of leaf shape data allowed quantification of the contribution of allometry to total variability and testing of its effect on species differentiation. Within pure oak species, leaf allometry was a significant component of leaf variation related to environmental variability, while when hybridization occurred leaf allometry was affected by the inheritability of both shape and size leaf traits. This study highlights the role of size and shape leaf covariation in the evolutionary processes of white oaks.

Temporal analysis of poplar woody root response to bending stress

Temperate perennial woody plants use different environmental signals to coordinate their growth and development in relation to seasonal changes. Preliminary evidences suggest that, even during dormancy, plants maintain effective metabolic activities and molecular mechanisms ensuring them an eventual recording of mechanical loads during winter times. Despite their great importance for productivity and survival, plant biology investigations have poorly characterized the root growth cycle and its response to environmental stresses. In this study, we describe the proteomic changes occurring over the time in poplar root either in the absence or in response to a bending stress; corresponding expression of cell cycle regulator and auxin transporter genes was also evaluated by reverse transcription polymerase chain reaction analysis. Our results confirm previous evidences on the effect of the bending stress on the anticipation of root growth resumption, providing additional insights on a temporal modulation of various plant metabolic processes involved in dormancy break, growth resumption and stress response in the bent root; these events seem related to the differential compression and tension force distribution occurring over the plant taproot.

An integrated approach to the characterization of two autochthonous lentil ( Lens culinaris ) landraces of Molise (south-central Italy)

Plant biodiversity must be safeguarded because it constitutes a resource of genes that may be used, for instance, in breeding programs. Lentil (Lens culinaris Medik.) is one of the most ancient crops of the Mediterranean region. Extensive differentiation of L. culinaris over millennia has resulted in a myriad of different landraces. However, in more recent times many landraces have disappeared consequent to environmental and socioeconomic changes. To promote the survival of endangered lentil landraces, we have investigated the genetic relationship between two ancient landrace cultivated in Capracotta and Conca Casale (Molise, south-central Italy) and widely spread commercial varieties using an integrated approach consisting of studies at morphological, DNA and protein level. Seeds of these two landraces were collected from local farmers and conserved in the Molise germoplasm bank. The two local landraces were well differentiated from each other, and the Conca Casale landrace was separated from the commercial varieties at morphological, protein and DNA level. The Capracotta landrace, was well separated from the commercial varieties, except Castelluccio di Norcia, at DNA level showing a more complex and heterogeneous segregation at morphological and biochemical level. The correlation between morphological, DNA and protein data, illustrates that proteomics is a powerful tool with which to complement the analysis of biodiversity in ecotypes of a single plant species and to identify physiological and/or environmental markers.

Role of micromorphological leaf traits and molecular data in taxonomy of three sympatric white oak species and their hybrids (Quercus L.)

Hybridisation and introgression occur with high frequency in the genus Quercus and interspecific hybrid individuals show patterns of morphological traits that might be influenced in different ways. Micromorphological leaf traits appear to be positive and stable in Quercus species, and by combining genetic and micromorphological analyses, it is possible to compare the patterns of variation in micromorphological leaf traits of pure and hybrid individuals. Trichomes and stomatal traits were examined using scanning electron microscopy at 150–2000 × magnification in sympatric oak species collected in a natural deciduous wood. Q. frainetto, Q. petraea and Q. pubescens appear to have a relatively predictable complement of trichome types. Both the pattern and quantitative values of each micromorphological trait examined (stomata and trichomes) have an important role in identifying hybrids and pure species; putative hybrids show a pattern of trichomes that is a combination of the parental types. These results, combined with the fact that micromorphological traits generally exhibit higher consistency, indicate that this source of information can be an excellent clue to hybridisation and introgression and useful in taxonomical, systematic and evolutionary studies on the European white oaks.

A statistical approach to species identification on morphological traits of European white oaks: evidence of morphological structure in Italian populations of Quercus pubescens sensu lato

Abstract Statistical analyses are applied to investigate morphological relationships among 309 oak trees belonging to European white oaks. The method is based on discriminant analysis for the species assignment, using several morphological features of young twigs, buds, leaves and fruits. Discriminant functions are then used to compute the probability of each individual belonging to a species. The results indicate that Quercus frainetto, Q. petraea and Q. robur are clearly discriminated; Q. virgiliana and Q. pubescens are more related, but well distinguishable; for Q. dalechampii an own morphological pattern is not obtained. Subsequently the work focuses on the distribution of Q. pubescens and Q. virgiliana in central—southern Italy and on the morphological structure of their populations. It results that Q. pubescens is dominant in east—northern district of Italian peninsula, while Q. virgiliana dominates in the west—southern district.