Figure 5

Genetic construction used in generation of PP2OETAt ( AtPP2-A1 -overexpression transgenic Arabidopsis thaliana ) and comparison of PP2OETAt and control plants in AtPP2-A1 expression and aphid activities on leaves. (a) The construct. The AtPP2-A1 (PP2) gene was inserted into the binary vector pBI121 at the BamH I and Sac I restriction sites to replace uidA, a reporter gene encoding β-D-glucuronidase. Nos P, promoter from the nopaline synthase-encoding gene (Nos); NPT II, kanamycin resistance gene; Nos T, Nos transcription terminator; 35S, the cauliflower mosaic virus 35S promoter. (b-e) Experiments were done with 35-day-old plants. Different letter labels in histograms indicate significant differences (ANOVA test, p < 0.01). (b) Real-time RT-PCR analysis of AtPP2-A1 expression in leaves. The gene transcript was quantified as mean ± SD (n = 3 repeats) relative to reference genes (EF1α and ACTIN2) and normalized to the null-template control. (c) Changes of aphid population in 24 hours. Uniform aphids were placed on lower sides of the top two expanded leaves (10 aphids/leaf). Leaf colonies were surveyed, the number of aphids that stayed in a leaf colony was scored, and percent decrease (mean ± SD; n = 120 leaf colonies) in the number of aphids that run away from the leaf colonies was calculated. (d) Total duration of the phloem phase in a four-hour EPG monitoring course. Uniform aphids were placed on upper sides of the top first expanded leaves. Feeding activities were detected immediately with a four-channel current amplifier system, and total duration of the phloem phase (mean ± SD; n = 20 aphids) was scored.