Fig. 6
Cytokinin-mediated shoot branching in CKX2-overexpressing tomato plants is mediated by a reduced auxin transport. A and B. Expression levels of PIN auxin efflux facilitator genes (SlPIN1, SlPIN4 and SlPIN7) in axillary buds (0.5 to 1.0 cm) harvested from the 3rd and 4th node of vegetative MT and CKX2-OE#2 plants (A) and in hypocotyl from 2-week-old seedlings (B). Data are means ± se of three biological replicates. C. Reduced basipetal auxin transport in CKX2-OE#2 compared to MT plants. Auxin ([3H]IAA) transport was measured in 10-mm hypocotyl sections of MT, CKX2-OE#2 and the experimental control (MT treated with 1-Naphthylphthalamic acid [NPA]). Data are means ± se (n = 10). D. Schematic representation of node position used in the decapitation experiment. E. Mean axillary bud length 10 days after decapitation in MT plants. F. Mean axillary bud length 10 days after decapitation in CKX2-OE#2 plants. Auxin, IAA (10 μM) was applied to the cut stem stump immediately after decapitation. Data are means ± se (n = 12). Letters indicate significant differences between treatments within the same genotype and node position. A and B: Student’s t-test; C: Tukey test, P < 0.05; E and F: Mann Whitney test; (*P < 0.05, ***P < 0.001)