Infection of ‘ C andidatus Phytoplasma ulmi’ reduces the protein content and alters the activity of detoxifying enzymes in A mplicephalus curtulus

It has been reported that insecticide‐detoxifying enzymes such as glutathione S‐transferases ( GST ) and esterases are affected by microbial infections in hemipteran insect vectors. The total protein content, and GST and α‐ and β‐esterase activities were quantified in ‘ C andidatus Phytoplasma ulmi’‐infected and uninfected adults of A mplicephalus curtulus Linnavuori & DeLong ( H emiptera: C icadellidae) at 25, 35, and 45 days after the acquisition access period ( AAP ) in the head‐thorax and abdomen sections. The total protein content was lower in phytoplasma‐infected leafhoppers 25, 35, and 45 days after the AAP . Thirty‐five days after the AAP , the GST and β‐esterase activities had increased (26 and 69%, respectively) compared to the control. However, 45 days after the AAP , the phytoplasma‐infected leafhoppers displayed lower GST (87%) and β‐esterase (253%) activities than the uninfected individuals. On the other hand, the α‐esterase activity proved to be unaffected by the phytoplasma infection. Forty‐five days after the AAP , females had a higher phytoplasma titer (46%) in their head‐thorax than in their abdomen sections, whereas males showed a higher titer in their abdomens (75%). In addition, the GST and β‐esterase activities in the abdomen were affected negatively by 96–98% as a result of the increasing ‘ Ca . Phytoplasma ulmi’ titer. These results indicate that an infection of ‘ Ca . Phytoplasma ulmi’ alters the metabolic activities of A . curtulus .