Rice ragged stunt virus including rice. The virus can only be transmitted by BPH and is not mechanically transmitted to plants. Rice plants infected with RRSV are stunted with whitish spindle-shaped outgrowths. Later the infected leaves become twisted with ragged edges, and may eventually turn brown. Rice plants may survive the infection, but yields are greatly reduced due to delayed flowering, incomplete panicle emergence, and unfilled grains. Symptoms of RRSV infection vary with the variety of rice and stage of growth. Most rice varieties of "Oryza sativa japonica" and "Oryza sativa indica" are susceptible to RRSV though several resistant varieties are available. Attempts to
Helitron (biology) Helitron (biology) Helitrons are one of the three groups of eukaryotic class 2 transposable elements (TEs) so far described. They are the eukaryotic rolling-circle transposable elements which are hypothesized to transpose by a rolling circle replication mechanism via a single-stranded DNA intermediate. They were first discovered in plants ("Arabidopsis thaliana" and "Oryza sativa") and in the nematode "Caenorhabditis elegans", and now they have been identified in a diverse range of species, from protists to mammals. Helitrons make up a substantial fraction of many genomes where non-autonomous elements frequently outnumber the putative autonomous partner. Helitrons seem to have a major role