Figure 6.

Overexpression of miR396, GRF1, or GRF3 negatively impacts syncytium size and nematode development. A, Reduced nematode susceptibility in transgenic plants overexpressing miR396, rGRF1, or rGRF3 is independent of root length. Three homozygous T3 lines overexpressing miR396b (line 16-4), rGRF1 (line 12-3), or rGRF3 (line 12-5) and showing significant decreases in root length were inoculated with J2 H. schachtii nematodes, and at 4 dpi the total number of penetrated nematodes was counted. Data obtained from two independent experiments showed no statistically significant differences between the transgenic lines and the wild-type control. Data are presented as means ± se (n = 20). B, Transgenic plants overexpressing miR396, rGRF1, or rGRF3 developed smaller syncytia than the wild type. Seedlings of the above-indicated lines along with the wild type (Col-0) were inoculated with J2 H. schachtii nematodes, and 2 weeks post inoculation at least 20 single nematode syncytia were randomly selected and measured. Data are presented as means ± se. Asterisks indicate statistically significance differences from wild-type plants at P < 0.05. C and D, Overexpression of miR396, rGRF1, or rGRF3 negatively impacts nematode development. Seeds of the above-indicated lines along with the wild type (Col-0) were planted, and seedlings were inoculated with J2 H. schachtii nematodes. After inoculation, the number of parasitic J2/J3 (C) and J4 (D) females was counted in the same plants. Data are presented as means ± se (n = 20). Asterisks indicate statistically significance differences from wild-type plants at P < 0.05.