Significant changes of temporal expression of CHI2 and CHI3 mRNAs. The transcript abundance changes during 72 hours of growth in chitinless, liquid PG-1 medium. The significant differences in temporal expression indicate functional constraint and are in accordance with the plurifunctionality of GH18 family members, respectively. Error bars (only the positive error bar is shown) represent the standard errors of the mean obtained from three independent time-course experiments. The asterisk designates significance at p < 0.05.