Figure 3.

PUB 1 overexpression reduces AM fungal colonization in wild-type M. truncatula roots. Wild-type roots were transformed with ProUb-GFP-PUB1 or an empty vector (control) and scored 24 d post-inoculation (dpi) with R. irregularis (1000 sp L⁻¹) for total AM fungal colonization (A) and according to Trouvelot method (B). m, intensity of the mycorrhizal colonization in the colonized root fragments; a, arbuscule abundance in the colonized root fragments; A, arbuscule abundance in the root system. C and D, Control (C) and ProUb-GFP-PUB1 (D) roots colonized by R. irregularis at 24 dpi. No apparent difference in arbuscule development was observed. Center lines show the medians, crosses the means, and box limits indicate the 25th and 75th percentiles as determined by R software; whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles. Numbers of plants are indicated in brackets. Significant differences were detected by two-sample t tests (* P ≤ 0.05).