Figure 1.
NHL3 overexpression levels correlate with resistance to virulent bacteria. A, Two micrograms of total RNA prepared from wild-type (WT) or four independent transgenic Arabidopsis lines with NHL3 under the control of the constitutive 35S promoter (S6, S7, S5, and S13) was used for northern blots and was hybridized with the indicated radioactively labeled cDNA probes (rRNA, 26S rDNA). B, Four-week-old plants were inoculated with P. syringae pv. tomato DC3000 at a concentration of 1 × 103 cfu mL–1. Bacterial titers in leaves at the indicated time points were determined. The figure shows the means and ses of a representative experiment. Line S13 consistently showed less bacterial growth in at least four other experiments. Bacterial growth in lines S7 and S5 are intermediate between S13 and the nonexpressing line S6 or wild-type plants. The four transgenic lines show differential expression of the transgene, and the relative mRNA level of NHL3 in the transgenic lines is indicated at the bottom of the figure. The level in the untransformed wild-type (Columbia [Col-0]) plants is set at a reference value of one. An inverse correlation between transgene expression and bacterial growth can be observed.