Cloning of an anthocyanidin synthase gene homolog from blackcurrant (Ribes nigrum L.) and its expression at different fruit stages.

Anthocyanidin synthase (ANS), a 2-oxoglutarate (2OG) and Fe(II)-dependent oxygenase, catalyzes the penultimate step in anthocyanin biosynthesis, from leucoanthocyanidins to anthocyanidins, the first colored compound in the anthocyanin pathway. In this study, a full-length, 1427-bp long cDNA named RnANS1, which is homologous to the anthocyanidin synthase gene, was cloned from blackcurrant using a homologous cloning strategy. RnANS1 is highly homologous to other plant ANS genes at both the nucleotide and amino acid sequence levels. The deduced protein contains domains conserved in the 2OG and Fe(II)-dependent oxygenase, and is phylogenetically closely related to Paeonia suffruticosa and Paeonia lactiflora. The expression of RnANS1 was upregulated during fruit maturation, and correlated with the accumulation of anthocyanins and soluble carbohydrates in the fruit. Further characterization of the structure and expression patterns of RnANS1 will clarify our understanding of anthocyanin biosynthesis in blackcurrant, and support the development of molecular approaches to manipulate anthocyanin production in this plant.

A new strategy for identification of currant (Ribes nigrum L.) cultivars using RAPD markers.

We developed a new approach using RAPD fingerprints to distinguish 37 currant cultivars from northeastern China based on optimization of RAPD by choosing 11 nucleotide primers and strict screening PCR annealing temperature. We found that the manual cultivar identification diagram (MCID) approach clearly developed fingerprints from 8 different primers that were useful for cultivar identification; a cultivar identification diagram (CID) was readily constructed. This CID allows efficient currant cultivar identification, providing information to separate all the currant cultivars from each other, based on the detail polymorphic bands from the corresponding primers, which were marked in the correct positions on the currant CID. According to the CID, 10 currant cultivars in 5 groups were randomly selected for the referable and workable identification of this strategy. The results proved the workability and efficiency of the MCID method, facilitating the identification of fruit cultivars with DNA markers. This MCID approach will be useful for early identification of seedlings in the nursery industry and protection of cultivar rights.

Development and characterization of microsatellite markers for the Cape gooseberry Physalis peruviana.

Physalis peruviana, commonly known as Cape gooseberry, is an Andean Solanaceae fruit with high nutritional value and interesting medicinal properties. In the present study we report the development and characterization of microsatellite loci from a P. peruviana commercial Colombian genotype. We identified 932 imperfect and 201 perfect Simple Sequence Repeats (SSR) loci in untranslated regions (UTRs) and 304 imperfect and 83 perfect SSR loci in coding regions from the assembled Physalis peruviana leaf transcriptome. The UTR SSR loci were used for the development of 162 primers for amplification. The efficiency of these primers was tested via PCR in a panel of seven P. peruviana accessions including Colombia, Kenya and Ecuador ecotypes and one closely related species Physalis floridana. We obtained an amplification rate of 83% and a polymorphic rate of 22%. Here we report the first P. peruviana specific microsatellite set, a valuable tool for a wide variety of applications, including functional diversity, conservation and improvement of the species.