Genetic structure of Ipomoea imperati (Convolvulaceae) in the Mediterranean region and implications for its conservation

Abstract

In this paper, we studied the relationships of the only surviving Italian population of Ipomoea imperati (Convolvulaceae), a pantropical sandy coastal species, in Sicily and other populations in the Mediterranean region. Herbarium samples which are representative of extinct populations growing in Campania (Italy) were also investigated together with populations from various Atlantic and Mediterranean localities. Chloroplast DNA microsatellites (cp-SSR) and nuclear ribosomal Internal Transcribed Spacer (ITS) sequences were jointly employed, in order to detect relationships among populations. Our aims were several-fold: (1) to clarify if the species is autochthonous in the Mediterranean basin or a post-Columbian introduction; (2) to investigate phylogeographic patterns in the species and (3) to establish the possible role of dispersal in explaining the patterns observed. Chloroplast microsatellite variation indicates that extinct Italian mainland populations of I. imperati from Campania are not closely related to the extant Sicilian one, as they do not share haplotypes. Chloroplast DNA microsatellite variation is largely between populations, and the within populations component accounts for only approximately 10%. CpDNA data is consistent with a single Mediterranean entry point hypothesis or with the notion that some populations display plesiomorphic variability. ITS data is congruent with the possibility that the presence of I. imperati in the Mediterranean is the result of transatlantic dispersal. The population from Sicily and extinct populations from Campania share an ITS type. A Bayesian analysis employing clock calibration data on an expanded ITS dataset with appropriate outgroups indicates that dates of transoceanic distribution are probably earlier than historical times.

Natural history of the narrow endemics Ipomoea cavalcantei and I. marabaensis from Amazon Canga savannahs

“…Next, we characterized the ribosomal RNA gene (rDNA) internal spacer ITS2 that is a standard type of the nuclear genome loci used in plant phylogenetic analysis and population genetics studies 17 , 18 . In all 217 analyzed sequences we did not detect insertions-deletions, thus ITS2 regions had the same length of 223 base pairs.…”

“…In contrast, little spatial structure was displayed by the distribution of the nuclear ITS2 polymorphisms. Thus, natural variation of plastome and ITS2 sequences suggested alternative demographic histories of Ipomoea populations in Carajás Cangas, which could reflect differences in gene allele dispersal by the seed or/and pollen 18 , 30 . Such contrasting genetic differentiations indicate maternally-biased plastome inheritance that limits plastome gene flow to the seed dispersal 30 .…”

Barcoding the kingdom Plantae: new PCR primers for ITS regions of plants with improved universality and specificity

“…The newly designed primer pairs are also expected to contribute to other applications such as conservation biology (Cennamo et al . ), forensic applications (Lee et al . ; Gausterer et al .…”

“…As most small-scale studies are more likely to suffer from fungus contamination instead of allelic variation, our plant-specific primers were designed to meet such requirements. The newly designed primer pairs are also expected to contribute to other applications such as conservation biology (Cennamo et al 2013), forensic applications (Lee et al 2010;Gausterer et al 2012) and market monitoring (Stoeckle et al 2011;Wallace et al 2012), in addition to the already-prevalent use of ITS for plant DNA barcoding, molecular phylogenetics and biodiversity studies.…”

Ipomoea imperati (Vahl) Griseb. (Convolvulaceae): nuevo xenófito invasor en la provincia de Cádiz (Sur de España)

“…), sureste de Sicilia (Turrisi, 2001), islas Azores y Cabo Verde (Hansen & Sunding, 1993), la isla de Porto Santo en el archipiélago de Madeira (Da Silva, 2002), y otros puntos de la Cuenca Mediterránea, especialmente hacia Oriente Medio (Turrisi, 2001(Turrisi, , 2007. Estudios genéticos recientes sugieren que la introducción de estas poblaciones en el Mediterráneo y Norte de África se produjo a raíz de una dispersión transoceánica relativamente antigua, seguida de dispersión secundaria hacia el Mediterráneo (Cennamo et al 2013).…”