Ultrastructural studies of the digestive system of the leafhopper Euscelidius variegatus infected with BEV bacteria

Abstract

The leafhopper Euscelidius variegatus Kirshbaum transmits plant diseases such as aster yellows and X-disease. It also harbours a BEV bacterium as a result of congenital infection . Since the bacterium can reduce the fecundity of the insect it has the potential of being used as a controlling agent for E. variegatus. Presently, little is known about the cytopathology of the host infected with BEV. This study aims to understand the damage done by the bacterium to the digestive system of E. variegatus and the defense reaction of the host to the bacterium.Digestive systems of BEV infected and non-infected adult females of E. variegatus were dissected in buffered insect saline and fixed in 2.5% glutaraldehyde in 0.1M sodium cacodylate (pH 7.2) for 1 hr. Tissues were post-fixed in 1% osmium tetroxide (pH 7.2) and dehydrated in alcohol/acetone series. These were blocked in Spurr resin and cut with a Reichart ultrotome. Thin sections were stained with uranyl acetate and lead citrate and were observed in a Zeiss EM 9S-2 electron microscope.