Figure 2: Silencing of Mds-1 in wheat confers immunity to susceptible plants.
(a) Transient silencing of Mds-1 in the susceptible genotype Newton confers immunity to Hessian fly biotype GP. Newton is a winter wheat and the susceptible recipient parents of several isogenic lines including Molly and Iris that contain different R genes12. Northern blot analysis of Mds-1 transcript in plants of untreated control, treated with the original virus (Vector) or treated with the modified virus that carried the 338-bp fragment of Mds-1 (RNAi) (Supplementary Fig. S2a). U, uninfested; I, infested plants. 28S, 18S and Mds-1 (900 bp) along with arrows on the left of the northern blot represent the locations of 28S rRNA, 18S rRNA and Mds-1 mRNA. An 18S rRNA image is given under the blot as loading control. Phenotypes of Hessian fly larvae on the control, vector- and RNAi-treated plants are given in the lower panel. Green arrows point to live larvae, the red arrow points to a dead larva. (b) Suppression of Mds-1 expression in transgenic Bobwhite plants confers immunity to Hessian fly biotype GP infestation. Bobwhite is a spring wheat line with high efficiency for genetic transformation. Bobwhite is susceptible to Hessian fly infestation. The upper panel is a northern blot of independent transgenic Bobwhite lines T385, T1630, T1639, T2030, T2357, produced with an RNAi construct (Supplementary Fig. S2b); and an empty vector-transformed Bobwhite wheat, V-BW, with (I) and without (U) Hessian fly infestation. Other denotations are the same as in a. The lower panel shows phenotypic differences among a non-transgenic Bobwhite plant (BW), an empty vector-transgenic plant (V-BW) and the Mds-1-silenced plants T1630 and T1639 after Hessian fly infestation. Growth of infested BW and V-BW was inhibited, but growth of infested T1630 and T1639 plants was comparable to that of uninfested control Bobwhite (UBW) plants. Resistance was observed in both seedling and adult transgenic plants.
