Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 2004
Publication Date: June 1, 2004
Citation: Haudenshield, J.S., Domier, L.L. 2004. Cellular distribution of RNA of seed-transmitted viruses in soybean embryos. Phytopathology. 94:S40. Technical Abstract: Soybean mosaic virus (SMV) and Tobacco ringsot virus (TRSV)cause serious virus diseases of soybean, and both viruses are transmitted vertically through infected seed. TRSV seed transmission approaches 90% in seed from infected plants. SMV is transmitted at a lower frequency (1% or less), although it has been reported to be as high as 30%, depending upon the virus isolate and soybean cultivar. We examined the cellular distribution of viral RNA in paraffin-embedded, thin sections of embryos from sytemically infected soybean plants by in situ RNA bybridization, using RNA probes derived from cloned cDNA of the 5' terminus of SMV and TRSV (RNA-2). Both TRSV and SMV invaded many cell types in stage 2, 3 and 4 soybean embryos, including cells of cotyledons, embryonic leaves, procambial tissue, and shoot apexes. Viral infection was observed in over 80% of the embryos examined for both viruses, suggesting that the lower frequencies of seed transmission reported for SMV must be the result of events occurring after developmental stage 4, possibly a reduced viability of the seed and/or SMV at maturity.