FIGURE 4.

Effect of ABA and GA₃ applications on GA biosynthesis (A) GA catabolism (B) and ABA catabolism-related (C) gene expression in roots of Moneymaker tomato plants non-colonized (NI) or colonized with R. irregularis (I). After 1 week of transplanting and inoculation with R. irregularis, a set of tomato plants (control) were treated with 0.1% ethanol solution, and three sets of plants were treated with ABA, GA₃ and GA₃+ABA. GA3 (5 μM) and ABA (75 μM) solutions were applied to soil twice per week. Gene expression was measured by qPCR 50 days after inoculation. qPCR data represents expression as M-value in gene expression relative to the biological replicate with lower expression in which the expression was designated to be 0 and all other samples were expressed relative to it. Values correspond to mean ± SE (n = 3). For each gene, bars with same letters are not significantly different (P = 0.05) according to Duncan’s multiple range test.