Products of LaTPS7 and LaCYP71D582 protect plants against insects
To the best our knowledge, limonene repels most herbivores including aphids, as shown in our previous work (Li et al. 2019). However, how limonene and its derivatives affect interactions between aphids and ladybugs remains undetermined. Therefore, to determine how limonene and its derivatives affect the relationship between aphids and ladybugs, we used a leaf disk assay and a Y-Tube olfactometer to assess responses from aphids and ladybugs, respectively, to tobacco leaves transiently transfected withLaTPS7and co-transfected withLaTPS7and LaCYP71D582 .
Our result show that tobacco leaves transfected with La TPS7, and leaves co-transfected with La TPS7 and La CYP71D582, repelled aphids at a rate of approximately 70% (Figure 7b). In contrast, La TPS7-expressing tobacco leaves attracted ladybugs at a rate of 48.33%, whereas leaves co-expressing La TPS7 andLa CYP71D582 attracted ladybugs at a rate of 58.33% (Figure 7a). These results suggest that limonene and carveol were more attractive to ladybugs than limonene alone.