Figure 4.

Overexpression of HUP26 leads to enhanced resistance to virulent Pst DC3000 inoculation via PR1 gene expression. (a) Schematic representation of hup26 knockout T-DNA lines (KO1: SALK_078717 and KO2: SALK_025645) regions and the 35S::HUP26 overexpression construct. (b) 4-week-old transgenic plants showed no developmental phenotype. Identification of homozygous hup26 mutants. Semi-quantitative analysis demonstrates that HUP26 is knocked-out in the hup26 mutants and confirms HUP26 overexpression transgenic lines. (c) Disease symptoms of Col-0, HUP26 OE, hup26 KO plants in 4 day after dip inoculation with Pst DC3000 at 1 × 10⁸ CFU/ml. Pictures were taken 4 days post inoculation. (d) Col-0, HUP26 OE, hup26 KO plants were dip inoculated with Pst DC3000 at 1 × 10⁸ CFU/ml. Bacterial growth was counted at 0 and 3 dpi. Error bars indicate standard deviations (n = 5). Student’s t-test; *P < .01. (e) The ion electrolyte leakage measurements were performed with Col-0, HUP26 OE, and hup26 KO plant leaf discs at 1 day after inoculated with Pst DC3000 at 1 × 10⁸ CFU/ml. Bars represent the average ion leakage measured for triplicates of ten leaf disks each (n = 10). Student’s t-test; *P < .01. (f) PR1 gene expression pattern analysis by qRT-PCR after bacterial pathogen inoculation. Total RNA was isolated from leaves of 4-week-old Col-0, HUP26 OE, and hup26 KO lines plants in response to Pst DC3000 after dip inoculation with Pst DC3000 at 1 × 10⁸ CFU/ml. Relative transcript levels of PR1 were determined by RT-qPCR. Error bars indicate standard deviations (n = 3). Student’s t-test; *P < .01, **P < .05, ***P < .0001