Papers by Egizia Falistocco
Frontiers in Plant Science, Jan 3, 2024
Advances in the study of polyploid evolution in wild populations Polyploidy is one of the most im... more Advances in the study of polyploid evolution in wild populations Polyploidy is one of the most important evolutionary events in plants and a major factor in speciation and plant diversification. About half of all higher plant species are categorized as recent polyploids; in addition, all species in which the genomes have been sequenced, have had in their ancestry at least one polyploidy event, a phenomenon known as whole-genome duplication (WGD) . The importance of polyploidy in plant evolution is well expressed with the concept "life on earth is predominantly a polyploid phenomenon" and largely confirmed by research in the past decades. Polyploidy is particularly frequent in wild species and in natural habitats. In this Research Topic "Advances in the Study of Polyploid Evolution in Wild Populations" seven articles have been published which cover major themes of this Research Topic: the emergence and establishment of polyploid taxa, cytotype distribution, polyploid complexes, mixed-ploidy populations, and chromosome rearrangement after polyploidization. The appearance and the success of polyploid lineages is often associated with the ability of polyploid individuals to adapt to various stress conditions and to colonize habitats unsuitable for the diploid ancestors. Thus, the frequency and the geographical distribution of polyploids in given areas should be closely related to the climatic history and ecogeographical heterogeneity of these areas. The study of Afonso et al. on Linum suffruticosum s.l. (Linaceae), a polyploid complex distributed throughout the western Mediterranean basin, revealed that the mosaic distribution of cytotypes is not fully explained by the environmental conditions. Reproductive and competitive interactions among cytotypes could have determined their current diversity and distribution. This study provides relevant information on mechanisms underlying the formation and persistence of polyploids. Jasione maritima (Campanulaceae) offers an interesting case study of the adaptive significance of polyploidy and the spatial distribution of cytotypes. J. maritima is a dune species with a parapatric distribution of diploid and tetraploid populations: Frontiers in Plant Science frontiersin.org 01
Caryologia
Foeniculum vulgare Mill. (2n=22) is an herbaceous species native to the Mediterranean region and ... more Foeniculum vulgare Mill. (2n=22) is an herbaceous species native to the Mediterranean region and naturalized in many temperate areas around the world. It includes subsp. piperitum and subsp. vulgare which are, respectively, the wild and cultivated forms. Fennel is of economic importance both as a vegetable crop and for its wide use in the food and pharmaceutical industries. In recent years, the therapeutic and pharmacological potential of this species has been widely analyzed, its cytogenetic traits have aroused less interest. Therefore, the intention of this study was to reduce this gap by investigating some aspects, such as the variations in its chromosome number and the occurrence of polyploidization events, so far neglected. By means of extensive chromosome counting, the presence of tetraploid cytotypes has been discovered both in the wild and cultivated fennel. Moreover, the analysis of pollen and PMCs at the tetrad stage provided evidence for spontaneous sexual polyploidizatio...
Caryologia
Apomixis is a rather widespread phenomenon in plants. It is defined as the asexual formation of a... more Apomixis is a rather widespread phenomenon in plants. It is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization. Some species are facultative apomicts and form seeds by means of sexual and apomictic pathways to different extents. This is the case of Poa pratensis, the Kentucky bluegrass, which reproduces by aposporous pseudogamous facultative apomixis. This grass is one of the most studied apomictic systems, however some aspects, such as the male meiotic behavior, have not been so far investigated. In this study the process of microsporogenesis in genotypes of P. pratensis with a different mode of reproduction was investigated. The analysis revealed an almost regular meiosis in the sexual plants whereas apomictic genotypes exhibited different levels of meiotic irregularities, mainly due to cell fusion and irregular segregation in I and II division. Our data did not reveal evident connections between t...
Valutazione dei rischi mutageno/cancerogeni relativi ad emissioni di fornelli a gas mediante test di mutagenesi su batteri e piante
La valorizzazione delle risorse genetiche agrarie della regione Umbria: la biodiversità vegetale in Umbria e la sua conservazione
Valutazione della cessione di sostanze genotossiche in acque minerali da contenitori in PET mediante test batterici ed organismi vegetali
The common fig (Ficus carica L.), a typical fruit tree of the Mediterranean area, is characterize... more The common fig (Ficus carica L.), a typical fruit tree of the Mediterranean area, is characterized by a complex breeding system which consists of two forms of tree, three functional floral forms and the symbiosis with the agaonid Blastophaga psenes, the wasp pollinator. The relationship between the reproduction of the plant and that of the insect is mutually obligatory because the pollen grains are transferred to the female flowers, only by the pollinator. On the other hand the wasps depend on the figs for their reproductive sites. Although genetic studies on common fig are recent, they allowed a rapid progress in the knowledge of biodiversity and germplasm characterization. Instead, the cytogenetics of the species is still unknown. The results of a research project dealing with the study of the biological diversity of F. carica following the cytogenetic approach are reported. Forty four genotypes, including wild plants, either caprifigs and female plants and cultivated common figs were examined. The chromosome count revealed that the majority of plants were 2n=26, as expected, but three were triploid with 2n=39. This result suggests that variations of the chromosome number could play a role in the evolution of the fig germplasm and induces to consider the important function of the wild forms as source of variability. This appears not only as genetic recombinants but also as polyploid variants. The analysis of pollen grains collected from caprifigs provided evidences in favour of this hypothesis with twice larger pollen grains found, as an indication of unreduced gametes. Moreover, the spreading of the mutants are facilitated by the vegetative propagation normally used by man in this fruit crop. This study contributed also to gain knowledge on the cytogenetics of F. carica by means the karyomorphological analysys and FISH mapping of rDNA sequences.
La storia millenaria del fico domestico
Preliminary trials on the characterization of Italian ecotypes of Dactylis glomerata L
Prime indagini di citogenetica in Bellis perennis, Bunias erucago, Chondrilla juncea, Sanguisorba minor
Advances in Agriculture, Horticulture and Entomology, 2020
Ficus carica L. is a classical fruit tree of antiquity, it goes back to the beginning of horticul... more Ficus carica L. is a classical fruit tree of antiquity, it goes back to the beginning of horticulture in the Mediterranean basin. Domestication produced substantial modifications on the primitive characteristics of the plant, for example by increasing the sugar content and the size of the fruit and determining a gradual shift toward vegetative propagation. However in the wild the spreading of the species is entirely dependent on seed. A very particular feature of this species is the reproductive biology which is regulated by a mechanism of extraordinary complexity based on the mutual symbiosis between the plant and its pollinator wasp Blastophaga psenes. This review provides the description of the intertwined life cycle plant-insect, of the floral biology and of the genetic control determining the different floral forms and the two sexual forms of tree. A part of this review is dedicated to the cytogenetic background of F. carica emphasizing the importance of recent investigations revealing the presence of polyploid cytotypes within wild and cultivated Italian populations. Considerations on the sexual reproduction and the genetic constitution of the fig cultivars are also reported.
Advances in the cytogenetics of Annonaceae, the case of Annona cherimola L
Genome, 2020
Annonaceae represent the largest extant family among the early divergent angiosperms. Despite the... more Annonaceae represent the largest extant family among the early divergent angiosperms. Despite the long-standing interest in its evolutionary and taxonomic aspects, cytogenetic studies on this family remain extremely few even on economically important species. With this study, we realized a detailed characterization of the chromosomes of Annona cherimola (2n = 14) by a combination of in situ hybridization techniques, fluorochrome banding, and karyomorphological analysis. FISH revealed that 45S and 5S rDNA sites are co-localized in correspondence to the secondary constrictions of the SAT-chromosome pair. Some hypotheses on the organization of the linked 45S and 5S rDNA repeats have been made. FISH with Arabidopsis-type telomeric arrays demonstrated that the A. cherimola telomeres are constituted by TTTAGGG sequences and that they are exclusively localized at the extremities of chromosomes. An insight into the chromosome structure of A. cherimola was obtained by the self-GISH procedure...
Plants, 2020
Cytogenetic research in Medicago sativa subsp. sativa L., the cultivated tetraploid alfalfa (2n =... more Cytogenetic research in Medicago sativa subsp. sativa L., the cultivated tetraploid alfalfa (2n = 4x = 32), has lagged behind other crops mostly due to the small size and the uniform morphology of its chromosomes. However, in the last decades, the development of molecular cytogenetic techniques based on in situ hybridization has largely contributed to overcoming these limitations. The purpose of this study was to extend our knowledge about the chromosome structure of alfalfa by using a combination of genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) techniques. The results of self-GISH (sGISH) suggested that a substantial part of the repetitive fraction of the genome of subsp. sativa is constituted by tandem repeats typical of satellite DNA. The coincidence of sGISH and C-banding patterns supported this assumption. The FISH mapping of the Arabidopsis-type TTTAGGG telomeric repeats demonstrated, for the first time, that the alfalfa telomeres consist o...
Phenotypic variation and performance of diploid subspecies of Dactylis glomerata L
Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2014
ABSTRACT Dactylis glomerata L. is one of the best known examples of a polyploid complex that incl... more ABSTRACT Dactylis glomerata L. is one of the best known examples of a polyploid complex that includes diploid (2n = 14), tetraploid (2n = 28) and hexaploid (2n = 42) types. The diploids, descending from the ancestors of the genus, are numerous, distinctforms adapted to specific environments and include all the morphological variation and ecological adaptation found in Dactylis. The objective of the present study was to shed more light on the differentiation of diploids and to obtain information for better exploiting the genetic resources of this species. To this end we carried out a discriminant analysis in the most widespread diploid subspecies based on a large number of morpho-physiological traits. We found that some characteristics, such as time to heading, time to flowering, vegetative regrowth, plant height and seed shattering are the most discriminant and enabled us to realize a more exact differentiation of the diploids with respect to the morphological criterion generally adopted. The results demonstrated that diploid taxa offer an interesting combination of relevant agronomical and ecological characteristics which could be useful in breeding programs to promote the use of this species in sustainable agriculture systems. We also performed cytological investigations and defined a general karyotype representative of the diploid Dactylis considered in this study.
Journal of Heredity, 2000
pigmentation pattern of the species ( Figure 1C,D;. There is, however, a range of phenotypes exhi... more pigmentation pattern of the species ( Figure 1C,D;. There is, however, a range of phenotypes exhibited by snakes possessing Sa and Ss alleles. Primarily affected are the size and pattern of dorsal and lateral body blotches, and the degree to which melanin is expressed in scales. Undoubtedly pigmentation pattern in Sa and Ss individuals is influenced by modifiers and/or the environment. Future work includes performing crosses between individuals possessing both the salmon (Sa and Ss) and albinism (Al) trait, and those that are homozygotes, Ss ϫ Ss. It is known that the Sa trait we report in captive B. constrictor occurs in certain populations from Panama (Porras 1999; Hardy D Sr, personal communication). According to Porras (1999, personal communication), B. constrictor from Isla Taboguilla ( Bahia de Panama) show the Sa trait (p. 60), and some individuals bear a strong resemblance to the Ss phenotype (pp. 51-52). D. Hardy, Sr. (personal communication) collected a juvenile female B. constrictor from the region of Gamboa, Panama, that showed the Sa condition. Because we have limited information on the Sa trait in B. constrictor, the extent of its geographic distribution remains to be established. Nonetheless, at present we are aware of no other localities than those provided above (Porras L, personal communication), and thus tentatively conclude that the Sa mutation has a limited geographic distribution in B. constrictor. Of importance, these data provide information that will be of utility to systematists and taxonomists working on this species. Based on our findings, populations of B. constrictor expressing the Sa or Ss pigmentation pattern should not be considered as distinct geographic races or other type of evolutionary unit. Rather it is our opinion that these populations show polymorphism with respect to pigmentation pattern.
Cytogenetic Investigations and Karyological Relationships of twoMedicago: M. SativaL. (Alfalfa) andM. ArboreaL
Caryologia, 1987
ABSTRACT A karyological survey with the purpose of comparing the chromosome complement of two tet... more ABSTRACT A karyological survey with the purpose of comparing the chromosome complement of two tetraploid species, Medicago sativa (alfalfa) and M. arborea, was undertaken as the two species will be used in a programme of breeding including somatic hybridization. The study of the karyotypes has shown that the two species could be easly separated on the basis of chromosome morphology. This will allow the indendification of heterokaryons in somatic hybrids. The karyological study allowed for some interesting hypotheses on the origin of the two species.
Cytotaxonomy ofTrifolium SubterraneumL
Caryologia, 1987
ABSTRACT Two subspecies (subterraneum and brachycalycinum) and one variety (yanninicum) of Trifol... more ABSTRACT Two subspecies (subterraneum and brachycalycinum) and one variety (yanninicum) of Trifolium subterraneum were studied. The analysis of the chromosome complements made using conventional staining techniques allowed to three different karyotypes to be distinguished. The main differences are the size of the satellite and of the nucleolar organizer region. The Hy-banding technique established the presence of large heterochromatic bands in the centromeric regions of each chromosome of the three taxa. On the bases of these results, subterraneum, brachycalycinum and yannicum can be considered as three different subspecies.
Monitoring of mutagens in urban air samples
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1999
This research was designed to examine the presence of mutagenic/carcinogenic compounds in urban a... more This research was designed to examine the presence of mutagenic/carcinogenic compounds in urban airborne particulates sampled with the inhalable PM-10 high volume sampler in two different streets of Brescia, a heavily industrialized town in northern Italy, using the Tradescantia/micronucleus test and a bacterial mutagenicity test (Kado test, a more sensitive version of the Ames test). In addition, the Tradescantia/micronucleus test was used for in situ monitoring of gaseous pollutants in other urban areas of Brescia and in two car tunnels, one with heavy car traffic in Perugia, a town in central Italy, and one in Brescia with moderate traffic. The Tradescantia-micronucleus test carried out on extracts of airborne particulates gave positive results only for the sample collected in the traffic-congested street where also higher bacterial mutagenicity was found. The in situ monitoring of the urban areas with the Tradescantia/micronucleus test always gave negative results. Monitoring carried out in the two car tunnels showed a significant increase in micronuclei frequency only in flowers exposed in the smaller and more polluted tunnel.
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Papers by Egizia Falistocco