Figure 1.

Isolation of the ien1 Mutant.

(A) Exogenous NAD⁺-induced PR1 gene expression in ien1 and wild-type (WT) seedlings. Seedlings grown on one-half–strength MS medium were treated with sprays of 1 mM of NAD⁺ solution. Total RNA was extracted from plant tissues collected 24 h later and subjected to RNA gel blot analysis. The UBQ5 gene was used as a loading control.

(B) Exogenous NAD⁺-induced PR1 gene expression in ien1 and wild-type soil-grown plants. Leaves of 4-week-old soil-grown plants were infiltrated with 1 mM of NAD⁺ solution. Total RNA was extracted from leaf tissues collected 24 h later and subjected to real-time qPCR analysis. Expression was normalized against constitutively expressed UBQ5. Data represent the mean of three independent samples with sd. Different letters above the bars indicate significant differences (P < 0.05, Student’s t test).