Fig. 3. CCA1 confers defense heterosis in hybrids without growth vigor costs.

a Phenotypes of the whole rosette of the CCA1-mutated F₁ hybrids and parents at 5 days post infiltration. Arrows show the four leaves of each plant inoculated with the pathogen. The scale represents 1 cm. b, d Fresh weight of the whole rosette of wild-type and CCA1-mutated hybrids and parents simultaneously with Pst DC3000 infiltration or not. 20-day-old (counted from the day the seedlings were transferred from MS plates to the soil) plants were infiltrated with Pst DC3000 or not infiltrated. The fresh weight of whole rosette was calculated 5 days later for both noninoculated and inoculated genotypes. Data are shown as the mean ± SD (n = 20 plants for each genotype without Pst DC3000 infiltration, and n = 30 plants for each genotype with Pst DC3000 infiltration). c, e MPH and BPH values of wild-type and CCA1-mutated hybrids calculated by whole rosette fresh weight at the same time without (noninfiltration) or with Pst DC3000 infiltration. Data are shown as the mean ± SD. The results in c and e are representative of three independent experiments, with measurements that were taken from independent samples grown and processed at different times. *p value < 0.05; **p value < 0.01; and ***p value < 0.001 (two-tailed Student’s t test).