Alessandra Gentile - Academia.edu (original) (raw)

Papers by Alessandra Gentile

Agriculture

The development of new seedless cultivar represents one of the most important goals in table grap... more The development of new seedless cultivar represents one of the most important goals in table grape breeding programmes worldwide. The most common technique to obtain new seedless cultivars is embryo rescue, an approach that allows the isolation of immature embryos and their cultivation in vitro. In this study, a total of 23 crosses (developed employing one seeded and one seedless parent) were performed during two seasons (2017 and 2018) for a total of 1140 seedlings. For each cross, the principal parameters related to the efficiency of the pollination were measured (harvested bunches, collected berries, recovered embryos/seeds and plants obtained). Based on these traits, statistical analyses were performed to calculate the female and male parental efficiency and to compare the two techniques of propagation employed: embryo rescue (7.8% of plants obtained) and gamic propagation (8.4%). Finally, the segregation of the SSR marker p3_VvAGL11 was evaluated on the progeny of four crosses ...

International Journal of Molecular Sciences

Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in ... more Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in the self-incompatibility process of clementine. The role of ASP-RICH is not known, but hypothetically they could sequester calcium ions (Ca2+) and affect Ca2+-dependent mechanisms. In this article, we analyzed the effects induced by clementine ASP-RICH proteins (CcASP-RICH) when expressed in the tobacco heterologous system, focusing on the male gametophyte. The aim was to gain insight into the mechanism of action of ASP-RICH in a well-known cellular system, i.e., the pollen tube. Pollen tubes of tobacco transgenic lines expressing CcASP-RICH were analyzed for Ca2+ distribution, ROS, proton gradient, as well as cytoskeleton and cell wall. CcASP-RICH modulated Ca2+ content and consequently affected cytoskeleton organization and the deposition of cell wall components. In turn, this affected the growth pattern of pollen tubes. Although the expression of CcASP-RICH did not exert a remarkable ...

Agriculture

Climate change (CC), which causes temperatures to rise steadily, is causing global warming. Risin... more Climate change (CC), which causes temperatures to rise steadily, is causing global warming. Rising temperatures can reduce plant yield and affect pollen characteristics. In particular, heat stress strongly influences pollen viability for its sensitivity to this extreme environmental condition. This work evaluated the effect of heat stress on olive pollen after in vitro incubation at different temperatures (20, 30, and 40 °C). Furthermore, the potential of selenium-methionine (Se-met) in mitigating the detrimental effects of heat stress on olive pollen was investigated. In particular, how thermal stress can affect pollen was evaluated by testing the effect of temperature on pollen germinability and morphology and cytosolic Ca2+ content. The results suggest that the heat stress at 40 °C caused a marked reduction in the germination rate, changes in the morphology of the external pollen wall, and a decreased response to Ca2+-agonist agents. On the contrary, in vitro treatment of pollen ...

Biology

The causal agent of mal secco disease is the fungus Plenodomus tracheiphilus, mainly affecting le... more The causal agent of mal secco disease is the fungus Plenodomus tracheiphilus, mainly affecting lemon tree survival in the Mediterranean area. Using a fully compatible host-pathogen interaction, the aim of our work was to retrieve the fungus transcriptome by an RNA seq approach during infection of rough lemon (Citrus jambhiri Lush.) to identify crucial transcripts for pathogenesis establishment and progression. A total of 2438 clusters belonging to P. tracheiphilus were retrieved and classified into the GO and KEGG categories. Transcripts were categorized mainly within the “membrane”, “catalytic activity”, and “primary metabolic process” GO terms. Moreover, most of the transcripts are included in the “ribosome”, “carbon metabolism”, and “oxidative phosphorylation” KEGG categories. By focusing our attention on transcripts with FPKM values higher than the median, we were able to identify four main transcript groups functioning in (a) fungus cell wall remodeling and protection, (b) dest...

Horticulturae

Not rinsing sodium bicarbonate (SBC) treated fruit with freshwater can reduce post-harvest decay,... more Not rinsing sodium bicarbonate (SBC) treated fruit with freshwater can reduce post-harvest decay, but it can also be phytotoxic to peel tissues. Film packaging delays the ageing of peel, due to the high in-package humidity, but this also stimulates the growth of pathogens. Thus, as stand-alone treatments, both SBC and film packaging present advantages, but also drawbacks. In this study, SBC phytotoxicity was effectively mitigated when ‘Simeto’ mandarins, subjected to a 2 min dip treatment in a 2% SBC solution, were packaged using Omni film (highly permeable to water vapor and gases) or Coralife SWAF 400 film (with a low permeability to water vapor, but moderately permeable to gases). In particular, the combination Coralife SWAF 400 film allowed the fruit to be stored for 7 d at 5 °C, or 14 d at 20 °C, with negligible changes in overall appearance, almost no loss caused by decay, and an average weight loss of 1.3%. The in-package air composition, similar to air in Omni packages, and ...

Horticulturae, 2021

In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species ar... more In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species are regulated by precise chilling and heating requirements. To investigate this aspect, sixty-one accessions of European pear (Pyrus communis L.) collected in Sicily were phenotyped for three consecutive years for harvest date, bud sprouting and blooming to determine both the chilling requirements and the threshold temperature using the Chill Days model. The whole germplasm collection was grown in two different experimental fields located at 10 and 850 m above sea level representing two Mediterranean-type climates in which pear is commonly cultivated. Results revealed a mean threshold temperature of 6.70 and 8.10 °C for the two experimental fields, respectively, with a mean chilling requirement ranging from −103 and −120 days. Through this approach, novel insights were gained on the differences in chilling requirement for early flowering cultivars to overcome dormancy. Furthermore, to bett...

Agronomy, 2021

The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with... more The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with early leaf removal (ELR) on the performance of the black grapevine variety Nerello Mascalese (Vitis vinifera L.). The research was carried out from 2015 to 2018 in a vineyard located in the Mount Etna area, East Sicily, Southern Italy. An average of about 8000 cm2 of leaves were removed from the ELR vines, corresponding to a canopy defoliation of 44% in 2017 and 30% in 2018. As for the stem water potential of both primary and lateral leaves, ELR-MT treatment showed the best performance (up to −0.4 MPa) among the four combinations. In 2017, no differences in yield/vine were found among treatments, whereas in 2018 the yield was significantly lower in ELR treatments. Among the different treatments performed, the ELR-MT showed the best results both in terms of physiological plant parameters (water status and photosynthetic activity) and fruit quality (higher concentration of sugars and tota...

Journal of Plant Pathology, 2008

SUMMARY To determine if rolABC genes of Agrobacterium rhizogenes could modify the susceptibility ... more SUMMARY To determine if rolABC genes of Agrobacterium rhizogenes could modify the susceptibility of Troyer citrange to dry root rot, conidial suspensions of a Fusarium solani strain isolated from citrus roots (PVCT1A) were used in cutting, leaf midrib and root inoculation assays of wild type (wt) and rolABC Troyer citrange. In all assays, the pathogen was reisolated equally well from wt and transformant. Interveinal chlorosis, wilt and defoliation of inoculated cuttings and leaf midribs, observed both in rolABC and wt, were more severe in transgenic lines. Two months after root inoculation with the pathogen, root weight was significantly reduced in transgenic lines. No root rot symptoms were observed on rolABC or wt lines, but wilting was more severe on wt. Cell-free fungal culture filtrate induced leaf wilt and defoliation within 10 days from immersion in the filtrate, without any significant difference between rolABC and wt lines. Scanning electron microscopy observations of infec...

Journal of Plant Pathology, 2005

To study the influence of rolABC Troyer citrange plants on potentially beneficial root-associated... more To study the influence of rolABC Troyer citrange plants on potentially beneficial root-associated bacteria, transgenic and non-transgenic plant lines were monitored over the course of one year. Culturable bacterial populations were not significantly different between rolABC and wild type lines, whereas the population of fluorescent pseudomonads varied according to the plant lines and the date of sampling. A total of 321 representative fluorescent pseudomonads were investigated to determine antagonistic activity against Fusarium solani and Phoma tracheiphila, and two different antagonistic groups were identified. IAA-producing Pseudomonas fluorescens strains were well distributed among transgenic and non-transgenic plant lines. A subset of 42 representative antagonistic P. fluorescens strains, characterized by ARDRA and ERIC-PCR, showed a high degree of DNA heterogeneity. Four main groups were identified. Three groups were heterogeneous and contained isolates from transgenic and non-...

Horticulturae, 2021

Rootstock choice has important effects on the horticultural and pathological traits of the citrus... more Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock effects has been a relevant research topic in citrus for many years, the main body of such study has been conducted at the biochemical level, while little effort has been directed to the determination of the rootstock influences at the molecular level. A comparative study of three combinations of scion and rootstock shows a positive correlation between the regulation of the fruit quality-related genes and the accumulations of bioactive compounds, as well as with acid degradation. Monitoring the anthocyanin accumulation during ripening shows the scion/rootstock combination can increase anthocyanin synthesis in the fruit, as well as vitamin C accumulation and acid degradation. Our result...

Agriculture, 2021

In Citrus, flower induction represents the transition from vegetative to reproductive growth. The... more In Citrus, flower induction represents the transition from vegetative to reproductive growth. The regulation of flower induction is mainly triggered by exposure to low temperatures and water-deficit stress, which activates the signaling cascade leading to an increased expression of the citrus orthologs of the FLOWERING LOCUS T (CiFT). In this study, the relationship between rootstock and flower induction under Mediterranean field conditions was investigated by monitoring the expression levels of the floral promoter CiFT2 in leaves of the pigmented sweet orange “Tarocco Scirè” grafted onto “C35” citrange and “Swingle” citrumelo rootstocks. The latter two are known to confer, respectively, high and low yield efficiency to the scion. In both rootstock/scion combinations, CiFT2 showed a seasonal expression with a peak during the inductive period in January triggered by cold temperature. The “Tarocco Scirè”/”C35” citrange combination showed the highest expression levels for CiFT2; this i...

Genes, 2020

Pink lemon is a spontaneous bud mutation of lemon (Citrus limon, L. Burm. f) characterized by the... more Pink lemon is a spontaneous bud mutation of lemon (Citrus limon, L. Burm. f) characterized by the production of pink-fleshed fruits due to an unusual accumulation of lycopene. To elucidate the genetic determinism of the altered pigmentation, comparative carotenoid profiling and transcriptional analysis of both the genes involved in carotenoid precursors and metabolism, and the proteins related to carotenoid-sequestering structures were performed in pink-fleshed lemon and its wild-type. The carotenoid profile of pink lemon pulp is characterized by an increased accumulation of linear carotenoids, such as lycopene, phytoene and phytofluene, from the early stages of development, reaching their maximum in mature green fruits. The distinctive phenotype of pink lemon is associated with an up-regulation and down-regulation of the genes upstream and downstream the lycopene cyclase, respectively. In particular, 9-cis epoxycarotenoid dioxygenase genes were overexpressed in pink lemon compared ...

Forests, 2020

The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) syst... more The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) system, a mechanism that promotes outbreeding and prevents self-fertilization. While the S-genotype of the most widely known pear cultivars was already described, little is known on the S-allele variability within local accessions. The study was conducted on 86 accessions encompassing most of the local Sicilian varieties selected for their traits of agronomic interest and complemented with some accessions of related wild species (P. pyrifolia Nakai, P. amygdaliformis Vill.) and some national and international cultivars used as references. The employment of consensus and specific primers enabled the detection of 24 S-alleles combined in 48 S-genotypes. Results shed light on the distribution of the S-alleles among accessions, with wild species and international cultivars characterized by a high diversity and local accessions showing a more heterogeneous distribution of the S-alleles, likely re...

Plants, 2020

Citrus is one of the most important fruit crops in the world. This review will discuss the recent... more Citrus is one of the most important fruit crops in the world. This review will discuss the recent findings related to citrus transformation and regeneration protocols of juvenile and adult explants. Despite the many advances that have been made in the last years (including the use of inducible promoters and site-specific recombination systems), transformation efficiency, and regeneration potential still represent a bottleneck in the application of the new breeding techniques in commercial citrus varieties. The influence of genotype, explant type, and other factors affecting the regeneration and transformation of the most used citrus varieties will be described, as well as some examples of how these processes can be applied to improve fruit quality and resistance to various pathogens and pests, including the potential of using genome editing in citrus. The availability of efficient regeneration and transformation protocols, together with the availability of the source of resistance, ...

Journal of the American Society for Horticultural Science, 1995

Protoplasts isolated from an embryogenic callus line of `Femminello siracusano' lemon [Citrus... more Protoplasts isolated from an embryogenic callus line of `Femminello siracusano' lemon [Citrus limon (L.) Burm. f.] were incubated with 0.5 μm toxin of Phoma tracheiphila (Petri) Kanc. et Ghik., the pathogen of the mal secco disease, which seriously damages most commercial lemon cultivars. Two toxin-tolerant cell lines were obtained, and plants were regenerated from each line. The selected protoclones were tested for their tolerance by exposing callus and protoplasts to the toxin and detecting chitinase (a pathogenesis-related protein) among the intra- and extracellular proteins extracted from leaves of regenerated plants and suspension culture, respectively. The tolerance of the protoclones in these tests was equivalent to the tolerant lemon cultivar Monachello, and they were substantially more tolerant than their mother cultivar Femminello siracusano.

Journal of the American Society for Horticultural Science, 2009

Seedlessness is an important trait in the evaluation of commercial mandarin for fresh consumption... more Seedlessness is an important trait in the evaluation of commercial mandarin for fresh consumption. However, in the last decade, the presence of seeds in fruit of cultivars considered as seedless has become a problem in different citrus-growing areas because the commercial value is depreciated. Seeds have appeared concomitantly with the introduction of new cultivars that appear to be cross-compatible. To overcome this problem, different strategies have been explored, but a definitive answer is still elusive. The search for alternatives contrasts with how little is known about the basis of the problem: the pollen-pistil incompatibility reaction in mandarin, and the intercompatibility relationship between different cultivars. In this work, we characterized the pollen-pistil incompatibility in the two commonly grown mandarin cultivars Fortune and Nova, and evaluated the intercompatibility relationship between six cultivars with different genetic origins; these cultivars included Fortune...

PloS one, 2018

The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in tempe... more The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in temperate climates. The Mount Etna area claims a large number of pear varieties differentiated due to a long history of cultivation and environmental variability, making this area particularly suitable for genetic studies. Ninety-five pear individuals were genotyped using the simple sequence repeat (SSR) methodology interrogating both the nuclear (nDNA) and chloroplast DNA (cpDNA) to combine an investigation of maternal inheritance of chloroplast SSRs (cpSSRs) with the high informativity of nuclear SSRs (nSSRs). The germplasm was selected ad hoc to include wild genotypes, local varieties, and national and international cultivated varieties. The objectives of this study were as follows: (i) estimate the level of differentiation within local varieties; (ii) elucidate the phylogenetic relationships between the cultivated genotypes and wild accessions; and (iii) estimate the potential genetic flo...

Tree Genetics & Genomes, 2008

Carob (Ceratonia siliqua L.) is a caesalpinoid legume tree showing labile sex expression. With th... more Carob (Ceratonia siliqua L.) is a caesalpinoid legume tree showing labile sex expression. With the main aims of identifying flower-expressed genes and of developing specific markers, 1,056 clones from a complementary DNA library of carob flowers were bidirectionally sequenced. A total of 1,377 high-quality expressed sequence tags were clustered into 1,096 unigenes. Basic Local Alignment Search Tool and Gene Ontology functional annotation allowed to identify several agronomically important genes, such as those involved in flower development and sexual reproduction, response to stress, galactomannan synthesis, and hormone pathways. Genes involved in the ethylene biosynthesis and response were quantified in developing flowers of three sex genotypes (male, female, and hermaphrodite) using quantitative reverse transcription polymerase chain reaction. The transcript levels of 1-aminocyclopropane-1-carboxylic acid oxidase, acting downstream in ethylene pathway, and Ethylene Insensitive 3 (EIN3)-like, a transcription factor involved in ethylene signaling, were directly correlated with maleness, indicating a possible role of ethylene in carob sex expression. Furthermore, the first set of carob genic microsatellites was developed, which might be useful for genotyping and genetic diversity analysis.

Theoretical and Applied Genetics, 1992

Nucellar calli from two citrus cultivars with known tolerance to real secco disease were chosen a... more Nucellar calli from two citrus cultivars with known tolerance to real secco disease were chosen as experimental material, to test the pathogen's response to culture filtrate (CF) and partially purified toxin (PPT), The response of the two calli to the CF was in reverse order to the known response of the two cultivars to natural and artificial inoculations with Phoma tracheiphila. HPLC analysis of P. tracheiphila CF indicated the presence of a relatively high level of indole acetic acid (IAA). The response of the two calli and protoplasts derived from these calli to increasing amounts of IAA in the culture media was in the same order as that of calli and protoplasts to CK In contrast, the responses to PPT of calli and protoplasts from these two types confirmed the relative tolerance of 'Femminello' lemon and 'Tarocco' orange trees to mal secco disease.

Journal of Agricultural and Food Chemistry, 2004

The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selecte... more The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selected accessions of Latinissima were evaluated in terms of yield, rheological properties, and sugar composition of the endosperm (LBG). The separation of the seed components in Latinissima and its seedlings yielded meanly 52.2% gum, 17.4% germ, and 30.5% tegument, whereas Tantillo furnished a lower gum yield (38.5%) and a higher yield of tegument (45.8%). The viscosity of 1% LBG aqueous solutions was measured at different shear rates (3-60 rpm), pH values (3.0-6.0), and temperatures (10-60°C). The best results were shown by Latinissima, whereas Tantillo provided always the poorest thickening capacity. The content of free simple sugars and sucrose in the raw flours, the total monosaccharide residues after acidic hydrolysis, the mannose/galactose ratio, and the distribution of polysaccharides by size exclusion chromatography accounted for the observed viscosities. The seeds of Latinissima showed the highest technological potential.

Agriculture

The development of new seedless cultivar represents one of the most important goals in table grap... more The development of new seedless cultivar represents one of the most important goals in table grape breeding programmes worldwide. The most common technique to obtain new seedless cultivars is embryo rescue, an approach that allows the isolation of immature embryos and their cultivation in vitro. In this study, a total of 23 crosses (developed employing one seeded and one seedless parent) were performed during two seasons (2017 and 2018) for a total of 1140 seedlings. For each cross, the principal parameters related to the efficiency of the pollination were measured (harvested bunches, collected berries, recovered embryos/seeds and plants obtained). Based on these traits, statistical analyses were performed to calculate the female and male parental efficiency and to compare the two techniques of propagation employed: embryo rescue (7.8% of plants obtained) and gamic propagation (8.4%). Finally, the segregation of the SSR marker p3_VvAGL11 was evaluated on the progeny of four crosses ...

International Journal of Molecular Sciences

Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in ... more Low-molecular-weight, aspartic-acid-rich proteins (ASP-RICH) have been assumed to be involved in the self-incompatibility process of clementine. The role of ASP-RICH is not known, but hypothetically they could sequester calcium ions (Ca2+) and affect Ca2+-dependent mechanisms. In this article, we analyzed the effects induced by clementine ASP-RICH proteins (CcASP-RICH) when expressed in the tobacco heterologous system, focusing on the male gametophyte. The aim was to gain insight into the mechanism of action of ASP-RICH in a well-known cellular system, i.e., the pollen tube. Pollen tubes of tobacco transgenic lines expressing CcASP-RICH were analyzed for Ca2+ distribution, ROS, proton gradient, as well as cytoskeleton and cell wall. CcASP-RICH modulated Ca2+ content and consequently affected cytoskeleton organization and the deposition of cell wall components. In turn, this affected the growth pattern of pollen tubes. Although the expression of CcASP-RICH did not exert a remarkable ...

Agriculture

Climate change (CC), which causes temperatures to rise steadily, is causing global warming. Risin... more Climate change (CC), which causes temperatures to rise steadily, is causing global warming. Rising temperatures can reduce plant yield and affect pollen characteristics. In particular, heat stress strongly influences pollen viability for its sensitivity to this extreme environmental condition. This work evaluated the effect of heat stress on olive pollen after in vitro incubation at different temperatures (20, 30, and 40 °C). Furthermore, the potential of selenium-methionine (Se-met) in mitigating the detrimental effects of heat stress on olive pollen was investigated. In particular, how thermal stress can affect pollen was evaluated by testing the effect of temperature on pollen germinability and morphology and cytosolic Ca2+ content. The results suggest that the heat stress at 40 °C caused a marked reduction in the germination rate, changes in the morphology of the external pollen wall, and a decreased response to Ca2+-agonist agents. On the contrary, in vitro treatment of pollen ...

Biology

The causal agent of mal secco disease is the fungus Plenodomus tracheiphilus, mainly affecting le... more The causal agent of mal secco disease is the fungus Plenodomus tracheiphilus, mainly affecting lemon tree survival in the Mediterranean area. Using a fully compatible host-pathogen interaction, the aim of our work was to retrieve the fungus transcriptome by an RNA seq approach during infection of rough lemon (Citrus jambhiri Lush.) to identify crucial transcripts for pathogenesis establishment and progression. A total of 2438 clusters belonging to P. tracheiphilus were retrieved and classified into the GO and KEGG categories. Transcripts were categorized mainly within the “membrane”, “catalytic activity”, and “primary metabolic process” GO terms. Moreover, most of the transcripts are included in the “ribosome”, “carbon metabolism”, and “oxidative phosphorylation” KEGG categories. By focusing our attention on transcripts with FPKM values higher than the median, we were able to identify four main transcript groups functioning in (a) fungus cell wall remodeling and protection, (b) dest...

Horticulturae

Not rinsing sodium bicarbonate (SBC) treated fruit with freshwater can reduce post-harvest decay,... more Not rinsing sodium bicarbonate (SBC) treated fruit with freshwater can reduce post-harvest decay, but it can also be phytotoxic to peel tissues. Film packaging delays the ageing of peel, due to the high in-package humidity, but this also stimulates the growth of pathogens. Thus, as stand-alone treatments, both SBC and film packaging present advantages, but also drawbacks. In this study, SBC phytotoxicity was effectively mitigated when ‘Simeto’ mandarins, subjected to a 2 min dip treatment in a 2% SBC solution, were packaged using Omni film (highly permeable to water vapor and gases) or Coralife SWAF 400 film (with a low permeability to water vapor, but moderately permeable to gases). In particular, the combination Coralife SWAF 400 film allowed the fruit to be stored for 7 d at 5 °C, or 14 d at 20 °C, with negligible changes in overall appearance, almost no loss caused by decay, and an average weight loss of 1.3%. The in-package air composition, similar to air in Omni packages, and ...

Horticulturae, 2021

In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species ar... more In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species are regulated by precise chilling and heating requirements. To investigate this aspect, sixty-one accessions of European pear (Pyrus communis L.) collected in Sicily were phenotyped for three consecutive years for harvest date, bud sprouting and blooming to determine both the chilling requirements and the threshold temperature using the Chill Days model. The whole germplasm collection was grown in two different experimental fields located at 10 and 850 m above sea level representing two Mediterranean-type climates in which pear is commonly cultivated. Results revealed a mean threshold temperature of 6.70 and 8.10 °C for the two experimental fields, respectively, with a mean chilling requirement ranging from −103 and −120 days. Through this approach, novel insights were gained on the differences in chilling requirement for early flowering cultivars to overcome dormancy. Furthermore, to bett...

Agronomy, 2021

The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with... more The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with early leaf removal (ELR) on the performance of the black grapevine variety Nerello Mascalese (Vitis vinifera L.). The research was carried out from 2015 to 2018 in a vineyard located in the Mount Etna area, East Sicily, Southern Italy. An average of about 8000 cm2 of leaves were removed from the ELR vines, corresponding to a canopy defoliation of 44% in 2017 and 30% in 2018. As for the stem water potential of both primary and lateral leaves, ELR-MT treatment showed the best performance (up to −0.4 MPa) among the four combinations. In 2017, no differences in yield/vine were found among treatments, whereas in 2018 the yield was significantly lower in ELR treatments. Among the different treatments performed, the ELR-MT showed the best results both in terms of physiological plant parameters (water status and photosynthetic activity) and fruit quality (higher concentration of sugars and tota...

Journal of Plant Pathology, 2008

SUMMARY To determine if rolABC genes of Agrobacterium rhizogenes could modify the susceptibility ... more SUMMARY To determine if rolABC genes of Agrobacterium rhizogenes could modify the susceptibility of Troyer citrange to dry root rot, conidial suspensions of a Fusarium solani strain isolated from citrus roots (PVCT1A) were used in cutting, leaf midrib and root inoculation assays of wild type (wt) and rolABC Troyer citrange. In all assays, the pathogen was reisolated equally well from wt and transformant. Interveinal chlorosis, wilt and defoliation of inoculated cuttings and leaf midribs, observed both in rolABC and wt, were more severe in transgenic lines. Two months after root inoculation with the pathogen, root weight was significantly reduced in transgenic lines. No root rot symptoms were observed on rolABC or wt lines, but wilting was more severe on wt. Cell-free fungal culture filtrate induced leaf wilt and defoliation within 10 days from immersion in the filtrate, without any significant difference between rolABC and wt lines. Scanning electron microscopy observations of infec...

Journal of Plant Pathology, 2005

To study the influence of rolABC Troyer citrange plants on potentially beneficial root-associated... more To study the influence of rolABC Troyer citrange plants on potentially beneficial root-associated bacteria, transgenic and non-transgenic plant lines were monitored over the course of one year. Culturable bacterial populations were not significantly different between rolABC and wild type lines, whereas the population of fluorescent pseudomonads varied according to the plant lines and the date of sampling. A total of 321 representative fluorescent pseudomonads were investigated to determine antagonistic activity against Fusarium solani and Phoma tracheiphila, and two different antagonistic groups were identified. IAA-producing Pseudomonas fluorescens strains were well distributed among transgenic and non-transgenic plant lines. A subset of 42 representative antagonistic P. fluorescens strains, characterized by ARDRA and ERIC-PCR, showed a high degree of DNA heterogeneity. Four main groups were identified. Three groups were heterogeneous and contained isolates from transgenic and non-...

Horticulturae, 2021

Rootstock choice has important effects on the horticultural and pathological traits of the citrus... more Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock effects has been a relevant research topic in citrus for many years, the main body of such study has been conducted at the biochemical level, while little effort has been directed to the determination of the rootstock influences at the molecular level. A comparative study of three combinations of scion and rootstock shows a positive correlation between the regulation of the fruit quality-related genes and the accumulations of bioactive compounds, as well as with acid degradation. Monitoring the anthocyanin accumulation during ripening shows the scion/rootstock combination can increase anthocyanin synthesis in the fruit, as well as vitamin C accumulation and acid degradation. Our result...

Agriculture, 2021

In Citrus, flower induction represents the transition from vegetative to reproductive growth. The... more In Citrus, flower induction represents the transition from vegetative to reproductive growth. The regulation of flower induction is mainly triggered by exposure to low temperatures and water-deficit stress, which activates the signaling cascade leading to an increased expression of the citrus orthologs of the FLOWERING LOCUS T (CiFT). In this study, the relationship between rootstock and flower induction under Mediterranean field conditions was investigated by monitoring the expression levels of the floral promoter CiFT2 in leaves of the pigmented sweet orange “Tarocco Scirè” grafted onto “C35” citrange and “Swingle” citrumelo rootstocks. The latter two are known to confer, respectively, high and low yield efficiency to the scion. In both rootstock/scion combinations, CiFT2 showed a seasonal expression with a peak during the inductive period in January triggered by cold temperature. The “Tarocco Scirè”/”C35” citrange combination showed the highest expression levels for CiFT2; this i...

Genes, 2020

Pink lemon is a spontaneous bud mutation of lemon (Citrus limon, L. Burm. f) characterized by the... more Pink lemon is a spontaneous bud mutation of lemon (Citrus limon, L. Burm. f) characterized by the production of pink-fleshed fruits due to an unusual accumulation of lycopene. To elucidate the genetic determinism of the altered pigmentation, comparative carotenoid profiling and transcriptional analysis of both the genes involved in carotenoid precursors and metabolism, and the proteins related to carotenoid-sequestering structures were performed in pink-fleshed lemon and its wild-type. The carotenoid profile of pink lemon pulp is characterized by an increased accumulation of linear carotenoids, such as lycopene, phytoene and phytofluene, from the early stages of development, reaching their maximum in mature green fruits. The distinctive phenotype of pink lemon is associated with an up-regulation and down-regulation of the genes upstream and downstream the lycopene cyclase, respectively. In particular, 9-cis epoxycarotenoid dioxygenase genes were overexpressed in pink lemon compared ...

Forests, 2020

The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) syst... more The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) system, a mechanism that promotes outbreeding and prevents self-fertilization. While the S-genotype of the most widely known pear cultivars was already described, little is known on the S-allele variability within local accessions. The study was conducted on 86 accessions encompassing most of the local Sicilian varieties selected for their traits of agronomic interest and complemented with some accessions of related wild species (P. pyrifolia Nakai, P. amygdaliformis Vill.) and some national and international cultivars used as references. The employment of consensus and specific primers enabled the detection of 24 S-alleles combined in 48 S-genotypes. Results shed light on the distribution of the S-alleles among accessions, with wild species and international cultivars characterized by a high diversity and local accessions showing a more heterogeneous distribution of the S-alleles, likely re...

Plants, 2020

Citrus is one of the most important fruit crops in the world. This review will discuss the recent... more Citrus is one of the most important fruit crops in the world. This review will discuss the recent findings related to citrus transformation and regeneration protocols of juvenile and adult explants. Despite the many advances that have been made in the last years (including the use of inducible promoters and site-specific recombination systems), transformation efficiency, and regeneration potential still represent a bottleneck in the application of the new breeding techniques in commercial citrus varieties. The influence of genotype, explant type, and other factors affecting the regeneration and transformation of the most used citrus varieties will be described, as well as some examples of how these processes can be applied to improve fruit quality and resistance to various pathogens and pests, including the potential of using genome editing in citrus. The availability of efficient regeneration and transformation protocols, together with the availability of the source of resistance, ...

Journal of the American Society for Horticultural Science, 1995

Protoplasts isolated from an embryogenic callus line of `Femminello siracusano' lemon [Citrus... more Protoplasts isolated from an embryogenic callus line of `Femminello siracusano' lemon [Citrus limon (L.) Burm. f.] were incubated with 0.5 μm toxin of Phoma tracheiphila (Petri) Kanc. et Ghik., the pathogen of the mal secco disease, which seriously damages most commercial lemon cultivars. Two toxin-tolerant cell lines were obtained, and plants were regenerated from each line. The selected protoclones were tested for their tolerance by exposing callus and protoplasts to the toxin and detecting chitinase (a pathogenesis-related protein) among the intra- and extracellular proteins extracted from leaves of regenerated plants and suspension culture, respectively. The tolerance of the protoclones in these tests was equivalent to the tolerant lemon cultivar Monachello, and they were substantially more tolerant than their mother cultivar Femminello siracusano.

Journal of the American Society for Horticultural Science, 2009

Seedlessness is an important trait in the evaluation of commercial mandarin for fresh consumption... more Seedlessness is an important trait in the evaluation of commercial mandarin for fresh consumption. However, in the last decade, the presence of seeds in fruit of cultivars considered as seedless has become a problem in different citrus-growing areas because the commercial value is depreciated. Seeds have appeared concomitantly with the introduction of new cultivars that appear to be cross-compatible. To overcome this problem, different strategies have been explored, but a definitive answer is still elusive. The search for alternatives contrasts with how little is known about the basis of the problem: the pollen-pistil incompatibility reaction in mandarin, and the intercompatibility relationship between different cultivars. In this work, we characterized the pollen-pistil incompatibility in the two commonly grown mandarin cultivars Fortune and Nova, and evaluated the intercompatibility relationship between six cultivars with different genetic origins; these cultivars included Fortune...

PloS one, 2018

The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in tempe... more The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in temperate climates. The Mount Etna area claims a large number of pear varieties differentiated due to a long history of cultivation and environmental variability, making this area particularly suitable for genetic studies. Ninety-five pear individuals were genotyped using the simple sequence repeat (SSR) methodology interrogating both the nuclear (nDNA) and chloroplast DNA (cpDNA) to combine an investigation of maternal inheritance of chloroplast SSRs (cpSSRs) with the high informativity of nuclear SSRs (nSSRs). The germplasm was selected ad hoc to include wild genotypes, local varieties, and national and international cultivated varieties. The objectives of this study were as follows: (i) estimate the level of differentiation within local varieties; (ii) elucidate the phylogenetic relationships between the cultivated genotypes and wild accessions; and (iii) estimate the potential genetic flo...

Tree Genetics & Genomes, 2008

Carob (Ceratonia siliqua L.) is a caesalpinoid legume tree showing labile sex expression. With th... more Carob (Ceratonia siliqua L.) is a caesalpinoid legume tree showing labile sex expression. With the main aims of identifying flower-expressed genes and of developing specific markers, 1,056 clones from a complementary DNA library of carob flowers were bidirectionally sequenced. A total of 1,377 high-quality expressed sequence tags were clustered into 1,096 unigenes. Basic Local Alignment Search Tool and Gene Ontology functional annotation allowed to identify several agronomically important genes, such as those involved in flower development and sexual reproduction, response to stress, galactomannan synthesis, and hormone pathways. Genes involved in the ethylene biosynthesis and response were quantified in developing flowers of three sex genotypes (male, female, and hermaphrodite) using quantitative reverse transcription polymerase chain reaction. The transcript levels of 1-aminocyclopropane-1-carboxylic acid oxidase, acting downstream in ethylene pathway, and Ethylene Insensitive 3 (EIN3)-like, a transcription factor involved in ethylene signaling, were directly correlated with maleness, indicating a possible role of ethylene in carob sex expression. Furthermore, the first set of carob genic microsatellites was developed, which might be useful for genotyping and genetic diversity analysis.

Theoretical and Applied Genetics, 1992

Nucellar calli from two citrus cultivars with known tolerance to real secco disease were chosen a... more Nucellar calli from two citrus cultivars with known tolerance to real secco disease were chosen as experimental material, to test the pathogen's response to culture filtrate (CF) and partially purified toxin (PPT), The response of the two calli to the CF was in reverse order to the known response of the two cultivars to natural and artificial inoculations with Phoma tracheiphila. HPLC analysis of P. tracheiphila CF indicated the presence of a relatively high level of indole acetic acid (IAA). The response of the two calli and protoplasts derived from these calli to increasing amounts of IAA in the culture media was in the same order as that of calli and protoplasts to CK In contrast, the responses to PPT of calli and protoplasts from these two types confirmed the relative tolerance of 'Femminello' lemon and 'Tarocco' orange trees to mal secco disease.

Journal of Agricultural and Food Chemistry, 2004

The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selecte... more The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selected accessions of Latinissima were evaluated in terms of yield, rheological properties, and sugar composition of the endosperm (LBG). The separation of the seed components in Latinissima and its seedlings yielded meanly 52.2% gum, 17.4% germ, and 30.5% tegument, whereas Tantillo furnished a lower gum yield (38.5%) and a higher yield of tegument (45.8%). The viscosity of 1% LBG aqueous solutions was measured at different shear rates (3-60 rpm), pH values (3.0-6.0), and temperatures (10-60°C). The best results were shown by Latinissima, whereas Tantillo provided always the poorest thickening capacity. The content of free simple sugars and sucrose in the raw flours, the total monosaccharide residues after acidic hydrolysis, the mannose/galactose ratio, and the distribution of polysaccharides by size exclusion chromatography accounted for the observed viscosities. The seeds of Latinissima showed the highest technological potential.