Genetic characterization and DNA barcoding of the coffee white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae) infesting Robusta coffee (Coffea canephora)

Abstract

The coffee white stem borer (CWSB), Xylotrechus quadripes (Chevrolat) is one of the most destructive pests of Arabica coffee plants (Coffea arabica), while, Robusta coffee (Coffea canefora) is free from CWSB attack for long time. However in recent years, CWSB infestation is also noticed on Robusta coffee in Polibetta, Mekur, Siddapura and Sunitikoppa in Kodagu district of Karnataka. Hence, the present study was aimed to confirm the infestation of CWSB infesting Robusta and comparing its population infesting Arabica coffee by performing DNA barcoding. The grubs of CWSB were collected by split-opening the infested Arabica and Robusta stems and persevered in 70% ethanol for molecular identification. In addition, infested stems were covered with nylon mosquito net to collect emerging adults and were preserved. The CWSB genomic DNA was extracted and the DNA concentration varied from 615.9 to 1110.6
ng/μL. The CWSB genomic DNA was amplified and was sequenced the mtCOI region. CWSB mtCOI genes were cloned and sequenced and they matched with high similarity in nucleotide Basic Local Alignment Search Tool search and Barcode of life (BOLD) identification. Neighbour joining (NJ) and Maximum likelihood (ML) phylogenetic tree analysis showed that the individuals of the same species clustered together based on the mtCOI sequence similarity, regardless of their collection site and host.