Identification and characterization of novel NBS-LRR resistance gene analogues from the pea.

Pea (Pisum sativum) is one of the most cultivated le-gumes in the world, and its yield and seed quality are affected by a variety of pathogens. In plants, NBS-LRR (nucleotide binding site-leucine-rich repeat) is the main class of disease resistance genes. Using degenerate primers deduced from conserved motifs in the NBS domain of known resistance genes, we identified 10 NBS sequences in three varieties of P. sativum. The deduced amino acid sequences of the iden-tified resistance gene analogues (RGAs) exhibited the typical motifs of the NBS domain (P-loop, kinase-2, kinase-3a, and the hydrophobic domain, GLPL) present in the majority of plant proteins belonging to the NBS-LRR class. Phylogenetic analysis showed that seven RGAs belonged to the non-TIR-NBS-LRR subclass and three to the TIR-NBS-LRR subclass. The results of this study provide insights into the structure of this class of resistance genes in the pea, and their evolution-ary relationships with those of other plant species.

Molecular characterization of barley yellow dwarf virus in Tunisia.

Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to characterize the B/CYDV isolates occurring in Tunisia, 240 barley leaves were randomly sampled from 6 fields following a North-South trend and analyzed by serological and molecular tests. DAS-ELISA results showed 40 positive samples with a prevalence of barley yellow dwarf virus (BYDV)-PAV (77.5%), followed by cereal yellow dwarf virus (CYDV)-RPV (25%) and BYDV-MAV (15%). Studies of the geographic distribution showed a high incidence of B/CYDV in the Tunisian Southern provinces. RT-PCR assays were performed to amplify the viral coat protein gene (CP) and sequence analyses revealed six BYDV-PAV haplotypes named PAV-TN1 to PAV-TN6. Phylogenetic analysis showed that the six Tunisian haplotypes were close to BYDV-PAV-II subspecies and had a strong similarity with Moroccan, Czech, French and German haplotypes. Although PAV-TN2 and PAV-TN5 showed up to 10% divergence from BYDV-PAV-II at the amino acid level, it seems to belong to the same subspecies but in a separated cluster. Our results will be important in developing appropriate control measures against BYDV disease in Tunisia.

Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2011-30 September 2011.

This article documents the addition of 299 microsatellite marker loci and nine pairs of single-nucleotide polymorphism (SNP) EPIC primers to the Molecular Ecology Resources (MER) Database. Loci were developed for the following species: Alosa pseudoharengus, Alosa aestivalis, Aphis spiraecola, Argopecten purpuratus, Coreoleuciscus splendidus, Garra gotyla, Hippodamia convergens, Linnaea borealis, Menippe mercenaria, Menippe adina, Parus major, Pinus densiflora, Portunus trituberculatus, Procontarinia mangiferae, Rhynchophorus ferrugineus, Schizothorax richardsonii, Scophthalmus rhombus, Tetraponera aethiops, Thaumetopoea pityocampa, Tuta absoluta and Ugni molinae. These loci were cross-tested on the following species: Barilius bendelisis, Chiromantes haematocheir, Eriocheir sinensis, Eucalyptus camaldulensis, Eucalyptus cladocalix, Eucalyptus globulus, Garra litaninsis vishwanath, Garra para lissorhynchus, Guindilla trinervis, Hemigrapsus sanguineus, Luma chequen. Guayaba, Myrceugenia colchagüensis, Myrceugenia correifolia, Myrceugenia exsucca, Parasesarma plicatum, Parus major, Portunus pelagicus, Psidium guayaba, Schizothorax richardsonii, Scophthalmus maximus, Tetraponera latifrons, Thaumetopoea bonjeani, Thaumetopoea ispartensis, Thaumetopoea libanotica, Thaumetopoea pinivora, Thaumetopoea pityocampa ena clade, Thaumetopoea solitaria, Thaumetopoea wilkinsoni and Tor putitora. This article also documents the addition of nine EPIC primer pairs for Euphaea decorata, Euphaea formosa, Euphaea ornata and Euphaea yayeyamana.