Figure 4.

Overexpression of AtJAR1 in tobacco. (a) Relative AtJAR1 transcript levels in JAR1 T₀ transgenic plants. RNA was isolated from leaf tissues collected before topping. Transcript levels were determined by qRT‐PCR. Values are means from three technical replicates. AtJAR1 transcript levels were normalized to actin and presented as fold to the AtJAR1 level in JAR1‐21 plant which is arbitrarily set at 1. (b) Total alkaloid levels of JAR1 T₀ plants. Total alkaloids were extracted and quantified from leaves 7 days after topping. The values shown are the means of total alkaloids (mg) per gram leaf dry weight from three technical replicates. (c) Transcript levels of five nicotine synthesis‐related genes in roots of two JAR1 T₁ lines. Roots from three plants were pooled at pre‐flowering stage. Transcript levels were determined by qRT‐PCR with three technical replicates. Transcript levels were normalized to actin and presented as fold to the vector control (VC) which was arbitrarily set at 1. (d) Nicotine content of two JAR1 T₁ lines. Nicotine was extracted and quantified from leaves at pre‐flowering stage. The values shown are the means of nicotine (mg) per gram of leaf dry weight from three biological replicates. VC, vector control. No significant difference was observed