Fig 8.

Effect of MeJA treatment on PVX-PVY infection. MeJA (+JA) or mock solution (−JA) as a control was applied to plants that were mock inoculated or inoculated with PVX-PVY. (A) The expression of threonine deaminase (TD) and proteinase inhibitor I (PI-I) mRNA was monitored by RT-PCR in mock-inoculated plants. The same RT reactions were used to amplify actin gene transcripts as a control. −RT, control without RT. (B) Representative disease symptoms displayed at 6, 8, and 12 d.p.i. Control plants exhibited the typical systemic symptoms associated with the viral synergistic interaction, while JA-treated plants exhibited milder symptoms at early times postinoculation (6 d.p.i.). By 8 d.p.i., MeJA-treated plants exhibited an enhanced necrosis response to PVX-PVY infection. (C) qRT-PCR was used to analyze the accumulation of PVX and PVY in plants that were treated with MeJA or mock solution and inoculated with PVX-PVY at 6 and 8 d.p.i. Data represent the means ± standard errors. Asterisks indicate significant differences in MeJA-treated plants compared with control plants at 6 d.p.i. (Student's t test, P = 0.05).