RESUMO
Type 2C protein phosphatases (PP2Cs) constitute a large family in most plant species but relatively few of them have been implicated in immunity. To identify and characterize PP2C phosphatases that affect tomato (Solanum lycopersicum) immunity, we used CRISPR/Cas9 to generate loss-of-function mutations in 11 PP2C-encoding genes whose expression is altered in response to immune elicitors or pathogens. We report that two closely related PP2C phosphatases, Pic3 (PP2C immunity-associated candidate 3) and Pic12, are involved in regulating resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Loss-of-function mutations in Pic3 led to enhanced resistance to Pst in older but not younger leaves, whereas such mutations in Pic12 resulted in enhanced resistance in both older and younger leaves. Overexpression of Pic3 and Pic12 proteins in leaves of Nicotiana benthamiana inhibited resistance to Pst, and this effect was dependent on Pic3/12 phosphatase activity and an N-terminal palmitoylation motif associated with localization to the cell periphery. Pic3, but not Pic12, had a slight negative effect on flagellin-associated reactive oxygen species generation, although their involvement in the response to Pst appeared independent of flagellin. RNA-sequencing analysis of Rio Grande (RG)-PtoR wild-type plants and two independent RG-pic3 mutants revealed that the enhanced disease resistance in RG-pic3 older leaves is associated with increased transcript abundance of multiple defense related genes. RG-pic3/RG-pic12 double mutant plants exhibited stronger disease resistance than RG-pic3 or RG-pic12 single mutants. Together, our results reveal that Pic3 and Pic12 negatively regulate tomato immunity in an additive manner through flagellin-independent pathways.
RESUMO
OBJECTIVE: To evaluate the effect of age, symptom duration, symptom presentation, presenting location, and type of acute upper respiratory tract infection (URI) on the receipt of inappropriate antibiotic prescriptions in adult patients. METHODS: A retrospective cross-sectional study was conducted within a U.S. Department of Veterans Affairs health system. A total of 500 adult patients with acute URI during a 1-year study period were randomly selected and evaluated for receipt of antibiotic prescriptions. Patients were excluded if they had an indication for antibiotics based on Centers for Disease Control and Prevention criteria, concomitant infection, or unreviewable patient record. Patients were grouped and compared by age, symptom duration, symptom presentation (purulence of secretions), presenting location, and type of URI. RESULTS: Overall, antibiotics were prescribed to 77% (219 of 283) of patients included in the study. Patients with purulent symptoms received a higher proportion of antibiotic prescriptions compared with those without purulent symptoms (P < 0.01). Patients seen in routine primary care received a lower proportion of antibiotic prescriptions compared with those seen in the emergency department or urgent care/primary care walk-in clinic (P < 0.01). No significant difference was observed in the proportion of antibiotic prescriptions based on symptom duration (P = 0.99) or age (P = 0.19). Patients with acute sinusitis or bronchitis received a higher proportion of antibiotics than those with acute pharyngitis or nonspecific URI (P < 0.01). CONCLUSION: Despite evidence-based practice guidelines for the rational use of antibiotics in patients with upper respiratory tract infections, these conditions are being treated inappropriately. Patient and provider factors play a role in the receipt of antibiotics. Further efforts, including those by pharmacists, are needed to improve the use of antibiotics for acute URI in adult patients.
