Paolo De Luca

Analysis of the genus Petagnaea Caruel (Apiaceae), using new molecular and literature data

In Southern Italy, an endemic monotypic genus belonging to family Apiaceae occurs: Petagnaea (P. gussonei), relict of Tertiary flora, belonging to subfamily Saniculoideae. At present, P. gussonei is an endangered species and is included in various lists of species deserving special protection. The genus belongs to scapose hemicryptophytes and shares a sciaphilous habitat (hygrophilous woodland). This study is aimed at doing a complete contribution about the evolutionary history of Petagnaea, using molecular markers as plastidial DNA (cpDNA), nuclear ribosomal DNA (rDNA) and data present in literature. We used nucleotide sequences from four regions of the chloroplast genome (rps16 intron, trnL(UAA) intron, atpB-rbcL intergenic spacer, and partial matK gene) to investigate possible haplotypes in Petagnaea populations. To have an idea of the molecular relationships of all populations of P. gussonei, the internal transcribed spacer (ITS) sequences, already employed in recent studies, were obtained for 18 populations. These sequences in combination with other Saniculoideae ITS sequences available from GenBank have been used for a further phylogenetic analysis. The results agree with the current classification of Saniculoideae in placing P. gussonei in tribe Saniculeae, since P. gussonei is in basal position to Sanicula. According to intraspecific chloroplast DNA diversity, no different haplotypes were detected. In addition to molecular data, morphology, cytology, phytochemistry and conservation status have been considered in the discussion.

Plastid DNA sequencing and nuclear SNP genotyping help resolve the puzzle of central American Platanus.

BACKGROUND AND AIMS Recent research on the history of Platanus reveals that hybridization phenomena occurred in the central American species. This study has two goals: to help resolve the evolutive puzzle of central American Platanus, and to test the potential of real-time polymerase chain reaction (PCR) for detecting ancient hybridization. METHODS Sequencing of a uniparental plastid DNA marker [psbA-trnH((GUG)) intergenic spacer] and qualitative and quantitative single nucleotide polymorphism (SNP) genotyping of biparental nuclear ribosomal DNA (nrDNA) markers [LEAFY intron 2 (LFY-i2) and internal transcribed spacer 2 (ITS2)] were used. KEY RESULTS Based on the SNP genotyping results, several Platanus accessions show the presence of hybridization/introgression, including some accessions of P. rzedowskii and of P. mexicana var. interior and one of P. mexicana var. mexicana from Oaxaca (= P. oaxacana). Based on haplotype analyses of the psbA-trnH spacer, five haplotypes were detected. The most common of these is present in taxa belonging to P. orientalis, P. racemosa sensu lato, some accessions of P. occidentalis sensu stricto (s.s.) from Texas, P. occidentalis var. palmeri, P. mexicana s.s. and P. rzedowskii. This is highly relevant to genetic relationships with the haplotypes present in P. occidentalis s.s. and P. mexicana var. interior. CONCLUSIONS Hybridization and introgression events between lineages ancestral to modern central and eastern North American Platanus species occurred. Plastid haplotypes and qualitative and quantitative SNP genotyping provide information critical for understanding the complex history of Mexican Platanus. Compared with the usual molecular techniques of sub-cloning, sequencing and genotyping, real-time PCR assay is a quick and sensitive technique for analysing complex evolutionary patterns.

Morphometric variation inLomelosia crenata (Dipsacaceae)

Morphometric characters on 118 herbarium specimens ofLomelosia crenata subsp.crenata (regarded as including subsp.pseudisetensis) were statistically evaluated to detect discontinuities in the variation pattern. Three morphotypes were detected: specimens with short stems and long calyx bristles, specimens with short stems and short bristles, and specimens with long stems and short bristles. The first morphotypic group is separated from the others, which are partly overlapping. These groups broadly correspond toL. crenata subsp.crenata, toScabiosa crenata var.glabriuscula, and toL. crenata subsp.pseudisetensis, respectively.

DNA Barcoding to Confirm the Morphological Identification of the Coral Trees (Erythrina spp., Fabaceae) in the Ancient Gardens of Naples (Campania, Italy)

The coral trees (genus Erythrina) have been fostering great interest among the botanists and gardeners of Naples, since their arrival in Europe in the second half of the 18th century. Numerous species were present in the royal and private botanical gardens of the region, but their number has decreased today. The purpose of this work was to verify which species occur nowadays in the public areas of Naples and associate them with the historical information about their introduction. The identification was carried out also by molecular methods, by means of sequencing nuclear and chloroplast DNA markers. The comparison of the sequences obtained for the specimens present in Naples with those present in the literature, together with a morphological examination, allowed us to identify with accuracy the species anciently introduced or nowadays cultivated in Naples.

Cyanobacterial mats from the Carrizal, a geothermal spring pool in Mexico

Cyanobacterial microflora is very diverse in different habitats over the world and closely connected with the ecology of the habitat. In particular, extreme habitats are colonised by numerous specialised morpho- and ecotypes which are unique to these ecologically specialised environments. A variety of methods are needed to characterize cyanobacterial assemblages in thermal water environments. We report here on the community structure of the cyanobaterial mats at the hot spring of the alkaline ad low sulphide artificial pool of “Carrizal” (Villa Emiliano Zapata, Mexico). The most common organisms were Anabaena sp., Phormidium sp. and Pseudoanabaena sp. Some filamentous cyanobacteria showed a 98%-95% 16S rDNA gene similarity with Oscillatoria sp. and cluster together with other filamentous cyanobacteria from the thermal environments.