Novel insights showing SecA protein localization and distribution of phytoplasma in insect vector Empoasca paraparvipenis.

Abstract

The Camptotheca acuminata witches-broom (CaWB-YNws) is one of the most severe diseases of C. acuminata and the insect vector is Empoasca paraparvipenis Zhang and Liu-CA (E. paraparvipenis-CA). Here, we reported the population of insect vector throughout the year in the Dashidong area, Wenshan, Yunnan Province, China. The occurrence of E. paraparvipenis was observed during the early epidemic stage in April, the summer peak epidemic stage in July, and the overwintering stage in November. Next, we established a set of immunofluorescence systems based on a polyclonal antibody against the SecA protein of the CaWB-YNws. We found that third instar E. paraparvipenis, after feeding the CaWB-YNws at different feeding times, demonstrated the movement from the anterior midgut to the midgut, where the pathogen assembled. Furthermore, after feeding on the infected host for 2 h, the third, fourth, and fifth instar insect vectors exhibit a green fluorescence signal in the anterior midgut, midgut, and salivary, as well as the anterior midgut and midgut of the fifth instar insect vectors. We found that the infection rate declined with increasing age. Our findings establish the interaction mechanism between the CaWB-YNws and the E. paraparvipenis and provide a new research insight for the prevention.