Diurnal Rhythms in Plant Defense Metabolites Figure 7. Diurnal rhythms and OS elicitation of OPDA, jasmonic acid and JA-related genes in roots. (A), (B) Mean (6SE) levels of normalized intensity of 12-oxophytodienoic acid (OPDA, m/z 291.20 at 479 s, C18H27O32) and jasmonic acid (JA, m/z 209.17 at 368 s, C12H17O32) in treated leaves and roots at each harvest time for two days (gray dotted lines) in control plants. After W+W (dashed lines with colors) or W+OS (solid lines with colors) treatments, their levels were examined in treated leaves (red) and roots (green). Gray boxes depict the dark period. Different symbols (* and #) indicate significant differences among the treatments at the indicated time point (P,0.05, one-way ANOVA with Bonferroni post hoc test). (C) Diurnal rhythms of gene accumulation involved in JA biosynthesis or signaling. AOS, allene oxide synthase; JAZ, jasmonate-ZIM-domain protein; COI1, coronatine insensitive 1. doi:10.1371/journal.pone.0026214.g007 AOS (allene oxide synthase) and two major JA signaling components, COI1 (coronatine insensitive 1) and JAZs (jasmonate-JIM-domain proteins) transcript accumulations showed diurnal rhythms (Figure 7C, Red line). NaCOI1 transcripts in leaves were induced at dawn and remained at low levels for the rest of the day (Figure 7C). NaJAZs levels in leaves peaked at 6 or 10 pm in leaves, while the same NaJAZ transcripts in roots peaked at 6 pm (Figure 7C). PLoS ONE | www.plosone.org 9 October 2011 | Volume 6 | Issue 10 | e26214