Abstract: The hexaploid herbaceous species Primula glaucescens Moretti and Primula spectabilis Tratt. (2n = 6x = 66) are two endemics of the Italian Pre-Alps protected by national and international laws. In order to plan conservation strategies for natural populations and to study the influence of the latest glaciation on them we developed a set of microsatellites markers for the endangered Primula species: ten primer pairs allowed analysis of polymorphic disomic loci in P. glaucescens samples and seven of them also amplified polymorphic disomic markers in P. spectabilis.
Notes: Kirsten Wolff and Giorgio Binelli contributed equally to the paper
Abstract: Aim In order to look for a possible centre of survival for the Norway spruce (Picea abies Karst.) in the south-western Alps, six natural populations of this area were investigated by means of genetic markers in order to assess the degree and the distribution of genetic diversity within the species.
Location Western and South-western Alps.
Methods Populations were genotyped using seven simple sequence repeat (SSR) markers. Basic population genetics parameters were estimated and the amount of genetic differentiation calculated.
Results A large amount of variability was found (0.59 < He < 0.67); genetic differentiation as measured by FST was 0.05, close to other similar studies; no isolation by distance was detected by a Mantel test. Analysis of molecular variance confirmed a high degree of variability within populations and a low degree of variability among populations. Finally, the number of populations from which those observed could have arisen was estimated by Bayesian analysis.
Main conclusions The results presented here suggest that the present populations derive their genetic make-up from three inferred clusters. The possible existence in this area of a relict/refuge population during the last glaciation is discussed.
Abstract: BACKGROUND AND AIMS: The assessment of the genetic variability and the identification of isolated populations within a given species represent important information to plan conservation strategies on a genetic basis. In this work, the genetic variability in five natural populations of Juniperus phoenicea, three from Sardinia, one from Cyprus and the last one in the Maritime Alps was analysed by means of ISSRs, on the hypothesis that the latter could have been a refugial one during the last glaciation. METHODS: ISSRs were chosen because of their ability to detect variation without any prior sequence information. The use of three primers yielded 45 reproducible, polymorphic bands, which were utilized to estimate the basic parameters of genetic variability and diversity. KEY RESULTS: All of the populations analysed harboured an adequate amount of genetic variability, with H(S) = 0.1299. The proportion of genetic diversity between populations has been estimated by G(ST) = 0.12. The three Sardinian populations are separated, as tested by AMOVA, from the Cyprus and the continental ones. CONCLUSIONS: The results indicate that geographical isolation has represented a major barrier to gene flow in Juniperus phoenicea. This work represents a first step towards a full genetic characterization of a conifer from the Mediterranean, a world biodiversity hotspot confronted with climate change, and thus contributes towards the planning of genetics-informed conservation strategies.
Abstract: Molecular markers derived from fruit modulated EST (Expressed Sequence Tags) and from other candidate genes controlling fruit traits are a useful tool to map genes and QTL (Quantitative Trait Loci) involved in fruit development and quality. Functional markers for fruit quality traits were developed for three apple cultivars (âFiestaâ, âPrimaâ, âDiscoveryâ) following three main approaches. On one hand, the public sequence database was screened for transcription factors (TFs) and 425 Malus EST were identified: 28 SSR containing sequences were tested for polymorphism. On the other hand, in a previous microarray analysis performed in our lab, 300 genes, differentially expressed during different fruit developmental stages, were identified. The corresponding ESTs provided the second source of functional markers and were assembled to identify unique transcripts: 153 sequences resulted to be unique while 147 redundant sequences were assembled in 36 contigs. In total 189 sequences were screened for the presence of SSR (Simple Sequence Repeat), the sequences not containing repeated elements were BLAST searched against PlantGDB-assembled Unique Transcript database (PUT) and the resulting PUTs were analyzed to identify repeated motifs. Furthermore, INDEL (INsertion/DELetion) and SNP (Single Nucleotide Polymorphism) were searched in the assembled sequences. The third source of ESTs was composed by sequences specifically expressed in fruit formation and in its physiological composition.
Finally, more then 100 PCR primer pairs were designed flanking SSR, INDEL or SNP containing regions or including most of the differentially expressed sequences while sequence reactions for the three cultivars were performed when polymorphism were not detected. SNPs detection was performed digesting PCR products with different restriction enzymes or by means of SSCP (Single Strand Conformation Polymorphism) while SSRs and INDELs were scored as length polymorphism. The fourty-seven polymorphic markers developed in this study will be useful to increase mapping resolution in âFiestaâ x âDiscoveryâ or âPrimaâ x âFiestaâ reference maps.
The work is part of the European project named HiDRAS (High-quality Disease Resistant Apples for a Sustainable Agriculture).
Notes: Function of D. Perini: co-applicant for funding,
Principal Investigator.
Third party funding : ⬠15.000 â by Milano Serravalle-Milano Tangenziale S.p.a.
