JA treatment enhances plant defense against CLCuMuV.

(A) Exogenous MeJA treatment delayed the incidence of symptom appearance. Six- to seven-week-old N. benthamiana (10–12 plants per treatment) were agroinoculated with CA+β, treated every other day with 50 μM MeJA or mock solution (ethonal), and recorded for the symptom appearance until 14 dpi. Means came from three independent experiments, Error bars represent SEM. (B-D) Different levels of symptoms (B: the 4^th level, C: the 2^nd level, and D: level 0 showing no symptom). (E) Exogenous MeJA treatment attenued disease symptoms level. Plants were scored for the appearance of symptoms at 14 dpi. (F) Total DNA was extracted from each plant respectively and subjected to real-time PCR (means±SEM, n = 7) to quantify viral DNA accumulation at 14 dpi. (G) Six- to seven-week-old N. benthamiana (10 plants per treatment) were agroinoculated with CA+βM1, treated every other day with 50 μM MeJA or mock solution (ethonal), Total DNA was extracted from each plant respectively and subjected to real-time PCR (means±SEM, n = 7) to quantify viral DNA accumulation at 14 dpi. The internal reference method was used to calculate the relative amount of viral DNA. The raw data of (E, F and G) were analysed by two-sample t-test to show significance level at 0.05 (*) and 0.01 (**). These experiments were repeated at least twice.