Plant Breeding Systems.

Speciation and Cytogenetics

Colonization and isolation are critical events in the evolutionary dynamics of plant populations. In this paper I review how spatial population structure of genetic markers provides insights into the evolutionary significance of episodes of colonization and isolation in the Mediterranean flora. I use as themes to structure my review the following topics: spatial structure induced by historical associations among populations of widespread species; population differentiation in relation to the evolution of closely related species with disjunct distributions; the potential effect of founder events during colonization on character evolution; and the conservation implications of spatial population structure. My review illustrates that the Mediterranean flora is full of examples that provide key insights into such evolutionary and conservation issues.

/pdf/population-differentiation-in-mediterranean-plants-insights-1nccdhlzrx.pdf

Population differentiation in mediterranean plants: insights into colonization history and the evolution and conservation of endemic species

Restriction map variation has been assayed in the slowly evolving chloroplast DNA (cpDNA) inverted repeat regions of 43 genera of the large and economically important legume tribe Phaseoleae and representatives of several allied tribes. Cladistic analyses of these data indicate that several plastome groups correspond well to subtribes recognized largely on the basis of mor- phological variation. Based on these cpDNA data, the tribe as a whole does not appear to be monophyletic, a result in accordance with current, morphologically-based hypotheses. Plastomes of several genera belonging to subtribes considered basal within Phaseoleae have as their sister groups plastomes of non-Phaseoleae tribes, notably Millettieae, the tribe considered to represent the ancestral stock from which diverse elements of Phaseoleae were derived. More unexpectedly, plastomes of the tribe Desmodieae fall within the clade that includes the most derived chloroplast genomes of Phaseoleae.

Chloroplast DNA Phylogeny of the Papilionoid Legume Tribe Phaseoleae

https://bibliotecadigital.ipb.pt/bitstream/10198/7048/1/Identification%20of%20phenolic%20constituents%20of%20Cytisus%20multiflorus.pdf

Identification of phenolic constituents of Cytisus multiflorus

Primula apennina Widmer is endemic to the North Apennines (Italy). ISSR were used to detect the genetic diversity within and among six populations representative of the species distribution range. High levels of genetic diversity were revealed both at population percentage of polymorphic band (PPB = 75.92%, H
 S = 0.204, H
 pop = 0.319) and at species level (PPB = 96.95%, H
 T = 0.242, H
 sp = 0.381). Nei gene diversity statistics (15.7%), Shannon diversity index (16.3%) and AMOVA (14%) detected a moderate level of interpopulation diversity. Principal coordinate and Bayesian analyses clustered the populations in three major groups along a geographic gradient. The correlation between genetic and geographic distances was positive (Mantel test, r = 0.232). All together, these analyses revealed a weak but significant spatial genetic structure in P. apennina, with gene flow acting as a homogenizing force that prevents a stronger differentiation of populations. Conservation measures are suggested based on the observed pattern of genetic variability.

High genetic diversity detected in the endemic Primula apennina Widmer (Primulaceae) using ISSR fingerprinting

https://digilander.libero.it/angelotroia/docs/withania_NPR_2007.pdf

Genetic and phytochemical difference between some Indian and Italian plants of Withania somnifera (L.) Dunal

Cytisus aeolicus Guss, is an endemic plant restricted to the isles of Vulcano, Stromboli and Alicudi in the Aeolian archipelago. All known populations were assayed for genetic variability using enzyme polymorphism. Allozyme variation at 16 loci coding for 10 enzyme systems was examined. The great majority of loci turned out to be monomorphic or fixed heterozygous. The observed genetic depauperation is indicative of historical factors, such as the bottleneck effect associated with migration, and the founder effect in population re-establishment. The low genetic diversity is largely partitioned within rather than among populations, indicating that extant populations have not been established long enough for divergence to have occurred. The genetic uniformity, combined with the scattered distribution of small populations, and the negative shift of population size point to a critically endangered species. Strategies for conservation are considered.

Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora

Viola pumila Chaix is a rare violet with a Eurasian-continental distribution. It has undergone a severe population decline during the last decades, and is endangered in Europe. Its southernmost extrazonal occurrence is in northern Italy, with only four populations. Inter-simple sequence repeat markers were used to detect genetic diversity level and distribution in the Italian stand and to compare it to a small sample from Germany. Estimates of genetic diversity revealed retention of genetic variation and weak genetic structure in the Italian populations of V. pumila. Comparable levels of genetic variation were detected in the German population. Principal component and cluster analyses on the whole data-set grouped individuals regardless of their geographical distribution, pointing out that genetic diversity in the V. pumila populations surveyed is homogeneously distributed. Analysis of molecular variance showed that most of the genetic variation is within populations rather than among them. Our results in...

Genetic diversity of the rare and endangered meadow violet (Viola pumila Chaix) at the southern margin of its range

https://onlinelibrary.wiley.com/doi/pdf/10.1111/oik.08176

Lucia Conte

Papers

High genetic diversity detected in the endemic Primula apennina Widmer (Primulaceae) using ISSR fingerprinting

Genetic and phytochemical difference between some Indian and Italian plants of Withania somnifera (L.) Dunal

Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora

Genetic diversity of the rare and endangered meadow violet (Viola pumila Chaix) at the southern margin of its range

Nectar chemistry is not only a plant's affair: floral visitors affect nectar sugar and amino acid composition