Comparison of protocols for the extraction of genomic DNA from Sharpshooters (Hemiptera: Cicadellidae) for the detection of Xylella fastidiosa

ABSTRACT: The bacterium Xylella fastidiosa, the causal agent of citrus variegated chlorosis (CVC), is dependent on vector insects for its spread and infection of citrus hosts. The insects, leafhoppers (Hemiptera: Cicadellidae) transmit the bacteria to healthy plants after feeding on infected plants. The objective of this study was to develop and compare methods for extracting genomic DNA from sharpshooters to detect X. fastidiosa. The DNA extraction from insects was performed according to a phenol-chloroform based DNA extraction in conjunction with two commercial kits, Dneasy® Plant Mini Kit and blood & tissue Dneasy® Handbook (Qiagen Inc., Valencia, CA, USA). The heads of the following species of sharpshooter were used: Dilobopterus costalimai, Acrogonia citrina, Oncometopia facialis, Bucephalogonia xanthophis, Macugonalia leucomelas and Homalodisca ignorata. Based on the numeric differences between independent samples, the results showed the use of the phenol:chloroform extraction method (36/50 positives) and the DNeasy® Plant Mini Kit (33/50) resulting in the most detections of X. fastidiosa from leafhopper samples. As these two methods detected Xylella in the greatest number of infected samples, they may be more efficient to use for detection purposes in leafhoppers.