The genome of all densoviruses (DNVs) so far isolated from mosquitoes or mosquito cell lines consists of a 4-kb single-stranded DNA molecule with a monosense organization (genus Brevidensovirus, subfamily Densovirinae). We previously reported the isolation of a Culex pipiens DNV (CpDNV) that differs significantly from brevidensoviruses by (i) having a ϳ6-kb genome, (ii) lacking sequence homology, and (iii) lacking antigenic cross-reactivity with Brevidensovirus capsid polypeptides. We report here the sequence organization and transcription map of this virus. The cloned genome of CpDNV is 5,759 nucleotides (nt) long, and it possesses an inverted terminal repeat (ITR) of 285 nt and an ambisense organization of its genes. The nonstructural (NS) proteins NS-1, NS-2, and NS-3 are located in the 5 half of one strand and are organized into five open reading frames (ORFs) due to the split of both NS-1 and NS-2 into two ORFs. The ORF encoding capsid polypeptides is located in the 5 half of the complementary strand. The expression of NS proteins is controlled by two promoters, P7 and P17, driving the transcription of a 2.4-kb mRNA encoding NS-3 and of a 1.8-kb mRNA encoding NS-1 and NS-2, respectively. The two NS mRNAs species are spliced off a 53-nt sequence. Capsid proteins are translated from an unspliced 2.3-kb mRNA driven by the P88 promoter. CpDNV thus appears as a new type of mosquito DNV, and based on the overall organization and expression modalities of its genome, it may represent the prototype of a new genus of DNV.The family Parvoviridae encompasses nonenveloped paraspherical viruses 22 to 25 nm in diameter with an icosahedral symmetry containing a single-stranded linear DNA genome 4 to 6 kb in length. The self-priming hairpin termini of their genomes to which the nonstructural (NS) protein NS-1 binds to initiate viral DNA replication are the hallmark of this family. On the basis of their host range, the family Parvoviridae is divided into two subfamilies: the Parvovirinae infecting vertebrates and the Densovirinae pathogenic for arthropods, mainly insects (18; also http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fr -fst-g.htm).Whereas all vertebrate parvoviruses so far studied have a monosense genome, i.e., with NS and structural (VP) genes located on the same strand, two main types of gene organization are known among invertebrate parvoviruses. Densoviruses (DNVs) belonging to the genera Densovirus and Pefudensovirus are characterized by having ambisense genomes, i.e., with coding sequences distributed on both strands (20). As representatives of the genus Densovirus, the Junonia coenia DNV (JcDNV) and Galleria mellonella DNV (GmDNV) possess a 6-kb genome containing in the 5Ј half of one strand the major open reading frame (ORF1) encoding the four VP polypeptides, whereas three ORFs (ORF2, ORF3, and ORF4) located in 5Ј half of the complementary strand encode NS polypeptides (7,21,22). These genomes have an inverted terminal repeat (ITR) of about 550 nucleotides (nt) able to form a Y-shaped structure at each extremity...

We report the development of nine microsatellite markers in the diploid legume Medicago truncatula. Five markers were obtained from microsatellite‐enriched genome libraries and four from sequences available in GenBank. Polymorphism was explored with plants from a natural population and cross‐amplification was tested in other Medicago and three other legume genera.