Making Use of Plant uORFs to Control Transgene Translation in Response to Pathogen Attack
pPR1-uORFsACD11 cassettes fine-tune AtLecRK-VI.2-mediated resistance to pathogens in transgenic N. benthamiana. (a, b) The growth phenotypes of indicated transgenic N. benthamiana plants. Photos were taken at 8 weeks after sowing (a). Plant heights (from soil to the top of plants) were calculated and showed in (b). (c) AtLecRK-VI.2 transcript accumulation confirmed by qRT-PCR. Transcript accumulation levels of AtLecRK-VI.2 were analyzed by qRT-PCR. CF was infiltrated into the indicated leaves. Total RNA was extracted 1 hour posttreatment. The NbELF18 gene was used as an internal reference. Bars represent standard errors from three biological replicates (;;,; Student’s -test). (d, e) Induced AtLecRK-VI.2 protein accumulation upon P. capsici infection. P. capsici mycelium was inoculated on the indicated leaves. Proteins was extracted 12 hours postinoculation. The α-FLAG antibody was used to detect the expression of AtLecRK-VI.2 protein. Equal loading of each sample is indicated by Ponceau staining. (f) Enhanced resistance to P. capsici infection in transgenic N. benthamiana. Lesion areas were calculated from three independent experiments with at least five leaves per replicate (;;,, Student’s -test). (g) Fine-tuning resistance to P. syringae hopq1-1 in transgenic plants. Error bars represent the ;; lowercase letters indicate statistical significance tested between multiple groups by one-way ANOVA at . (h) Fine-tuning systemic acquired resistance to P. syringae hopq1-1 in transgenic plants. Three lower leaves on each 4-week-old soil-grown plant were infiltrated with H2O or P. syringae hopq1-1 suspension (). Two systemic leaves were challenge-inoculated with a P. syringae hopq1-1 suspension () at 24 hours after the last infiltration. Three days later, eight leaves were collected to examine pathogen growth. Error bars represent the ;; lowercase letters indicate statistical significance tested between multiple groups by one-way ANOVA at . (i) A model for the usage of uORFsACD11 in precisely engineering crop disease resistance at required levels to minimize negative impacts on plant growth. uORFsACD11 inhibits downstream gene translation in normal conditions and releases it upon pathogens. uORFsACD11 coupled with PR1 promoter can confer fine-tuned resistance in transgenic plants specifically when plants are facing pathogen threats.