Fig. 3.

Role of PAL activity and JA biosynthesis in the resistance response of Oryza glaberrima TOG5681. (A, B) Number of galls and nematodes in rice roots 14 d after infection with 250 J2 Meloidogyne graminicola. Effects of (A) PAL inhibitor l-2-aminooxy-3-phenylpropionic acid (AOPP, 100 µm) and (B) lipoxygenase inhibitor salicyl hydroxamic acid (SHAM, 200 µm) on plant susceptibility to nematode infection. Leaves of eight plants were sprayed with inhibitor or water (as control) and plants were inoculated with nematodes 24 h later. The experiment was repeated three times. (C) Effect of treatments on gene expression levels in rice roots 24 h after foliar treatment with the inhibitors. Gene expression levels were measured by RT-qPCR assays and normalized using three internal reference genes: OsEIF5C, OsREF3 and OsEXPNAR. Data shown are relative transcript levels compared with control roots of water-sprayed plants (expression level set at 1). Bars represent the mean expression level ± s.e. from two independent biological replicates and three technical replicates, each containing a pool of six plants. Asterisks indicate significantly different expression levels (*P < 0·1; **P ≤ 0·05).