Figure 8.

Phenotype of SDH1-1 RNAi transgenic plants. A, Schematic diagram of the construct used to down-regulate SDH1-1. The arrows indicate the SDH1-1 sequence (first exon) cloned in both orientations in the RNAi pHELLSGATE4 vector. Sense and antisense SDH1-1 transcribed sequences would be separated by the plant pyruvate orthophosphate dikinase (PDK) intron, generating an ihpRNA. B, Northern-blot analysis of SDH1-1 expression in five RNAi T₂ plants and two wild-type controls. Each lane was loaded with 10 μg of total RNA isolated from flowers. The blot was hybridized with a SDH1-1 specific probe and then with an actin probe as loading control. RNAi plants had decreased SDH1-1 mRNA levels. C and D, Pollen abortion in SDH1-1 RNAi plants. Alexander staining was performed on two wild-type and five RNAi T₂ anthers. Sections C and D show the staining of one RNAi plant and one wild-type plant, respectively. Quantitative determination of pollen abortion was done by counting viable, purple pollen grains, and aborted, green pollen grains, and the results obtained are shown under the images. Bars = 20 μm. E, Seed set is reduced in SDH1-1 RNAi plants. Seed set per silique was scored for the first eight siliques from five T₂ RNAi plants (1–5) and two wild-type control plants (wt). Error bars represent sds.