Expression of PSS1 enhances SDS resistance in transgenic soybean plants under growth chamber conditions. A, Schematic depiction of promoter-PSS1 fusion genes along with the CaMV 35S promoter-fused bar gene in three binary plasmids used to generate transgenic soybean plants. B, Responses of the transgenic lines to root infection with F. virguliforme Mont-1 in growth chambers. Plants with foliar SDS scores of 2 or less were considered resistant, and those with scores greater than 2 were considered susceptible. Percentage resistant and susceptible R1 progeny are presented for each of the PSS1 transgenes generated by fusing the PSS1 gene to Prom1, Prom2, and Ubi10 promoters. For each transgenic event, 15 R1 plants were studied. The experiment was repeated two more times and showed similar results. Foliar SDS symptoms for individual plants were scored 4 weeks following planting. MN1606, SDS-resistant control; WT, transgene recipient nontransgenic cv Williams 82 (W82) as the SDS-susceptible control. C, RT-PCR analysis of the transgenic R1 plants for PSS1 transcripts. Lanes 1 to 6, RT-PCR products from F. virguliforme-infected roots of three independent lines carrying promoter Prom1 fused to PSS1; lanes 7 to 12, RT-PCR products from F. virguliforme-infected roots of three independent lines carrying promoter Prom2 fused to PSS1; and lanes 13 to18, RT-PCR products from F. virguliforme-infected roots of three independent lines carrying promoter Ubi10 fused to PSS1. For each independent transgenic line, two R1 SDS-resistant plants (lanes 1–18) were analyzed. Lanes 19 to 21, RT-PCR products from F. virguliforme-infected roots of three independent R1 progeny plants that were SDS susceptible. D, Relative biomasses of F. virguliforme measured by genomic DNA qPCR of the FvTox1 gene among three independent transgenic lines. Root samples were collected 2 weeks following infection with the F. virguliforme Mont-1 isolate in a growth chamber. 206-7-1, Transgenic line carrying Prom1-PSS1; 207-3-6, transgenic line carrying Prom21-PSS1; 227-9-1, transgenic line carrying the Ubi10-1-PSS1 fusion gene; W82, cv Williams 82. Asterisks indicate statistical significance at P < 0.05 when compared with the biomass of F. virguliforme in cv Williams 82.