The impact of feeding injury by the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), and bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on susceptible and resistant wheat, Triticum aestivum L., near-isogenic lines 'Tugela' (susceptible), Tugela-Dn1 (antibiotic), Tugela-Dn2 (tolerant), and Tugela-Dn5 (antixenotic) was evaluated by assessing photosyn...

Long-range cis elements are critical regulators of gene transcription, particularly for paralogous genes clustered on a unique chromosomal region. Such are the five PADI genes in 1p35–36 encoding peptidylarginine deiminases. These enzymes catalyze deimination, or citrullination, a calcium-dependent post-translational modification of proteins which has been implicated in gene regulation and in t...

Understanding the mode of origin of asexuality is central to ongoing debates concerning the evolution and maintenance of sexual reproduction in eukaryotes. This is because it has profound consequences for patterns of genetic diversity and ecological adaptability of asexual lineages, hence on the outcome of competition with sexual relatives both in short and longer terms. Among the possible rout...

the bird cherry-oat aphid, rhopalosiphum padi (l.) is a serious threat to several cereal crops. host-plant resistance to this aphid could be especially valuable in cereal crops pest management. therefore, we evaluated the development, survivorship, reproduction and population growth parameters of r. padi as resistance indices among six wheat cultivars, including gaskojen, tajan, falat, saysonz,...

Host choice and winter-host leaving in emigrants of bird cherry-oat aphid, Rhopalosiphum padi (Linnaeus), were investigated in the laboratory. In settling choice tests, emigrants collected from the winter host, Prunus padus, preferred this plant over a summer host, oats. Emigrants which had left P. padus for up to 24 h did not express a preference as a group, and those which had left for 24-48 ...

The presence of an endophytic fungus, Acremonium coenophialum, in tall fescue (Festuca arundinacea) deterred aphid feeding by Rhopalosiphum padi and Schizaphis graminum. Both species of aphid were unable to survive when confined to endophyte-infected tall fescue plants. Feeding deterrents and toxic factors to R. padi and Oncopeltus fasciatus, large milkweed bug, were primarily associated with a...

Sexual aggregation inyo}yed in coajugative transfer of Ehterococcus,faecalis plasmid pADI is enhanced by the sex pheremone cADI, which is excreted from recipient cells. A membrane-anchored 137 kDa protein is a pADI-encoded aggregation substance designated asal, which is responsible for cell-cell contact and leads to the aggregation of cells. An AD74 protein is a proteolytic product correspondin...