Submitted to: ARS Sclerotinia Initiative Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/31/2004
Publication Date: 1/18/2005
Citation: Clough, S.J., Hubbard, S., Zhang, Y., Davidson, A., Rioux, S., Calla, B., Simmonds, D. 2005. Microarray analysis of oxalate oxidase transgenic soybean challenged with Sclerotinia sclerotiorum [abstract]. ARS Sclerotinia Initiative Annual Meeting. Available: http://www.whitemoldresearch.com/posters2004/Clough.pdf.
Technical Abstract: Oxalate is a major virulence factor of Sclerotinia sclerotiorum. Research involving fungal mutants as well as transgenic plants, has clearly shown that virulence of S. sclerotiorum is substantially reduced if oxalate is removed from the interaction. We are utilizing a transgenic soybean plant that constitutively produces the oxalate-degrading enzyme, oxalate oxidase (OxO), to study how soybean plants respond to oxalate and S. sclerotiorum. Freshly opened flowers, inoculated between the standard and wing petals with 10 ul of ascospores (5000 ascospores/10 ul of 0.006% Triton X-100 in water), were incubated for 3 days in humid petri dishes and used for inoculum. The central leaflet of V4 leaves of the transgenic line 80(30)-1 and its parent AC Colibri were inoculated behind the first lateral vein with infected flowers. Leaves were collected rapidly and frozen in liquid nitrogen within 30 seconds after removal from the plant. The lateral two leaflets were removed from the leaf, the remaining leaflet was removed from the plant by cutting the petiole close to the main stem, the infected flower was removed and the stage of invasion determined under a dissecting microscope. The leaflet was cut transversely 3 cm beyond its base and together with the petiole was frozen in liquid nitrogen. Two sample times were taken: 1. early appressorial formation (10-12 hour post inoculation) and 2. early vascular entry (18-20 hour post inoculation).