The two most widespread biotypes of Bemisia tabaci (Gennadius) in southern Europe and the Middle East are referred to as the B and Q-type, which are morphologically indistinguishable. In this study various DNA markers have been developed, applied and compared for studying genetic diversity and distribution of the two biotypes. For developing sequence characterized amplified regions (SCAR) and cleaved amplified polymorphic sequences (CAPS) techniques, single random amplified polymorphic DNA (RAPD) fragments of B and Q biotypes, respectively, were used. The CAPS were investigated on the basis of nuclear sodium channel and the mitochondrial cytochrome oxidase I genes (mtCOI) sequences. In general, complete agreement was found between the different markers used. Analysis of field samples collected in Israel for several years, using these markers, indicated that the percentage of the Q biotype tends to increase in field populations as time progresses. This may be attributed to the resistance of the Q biotype to neonicotinoids and pyriproxyfen and the susceptibility of the B biotype to these insecticides.
Bibliographical noteFunding Information:
The authors thank the Drs I. Bedford (John Innes Centre, UK) and G. Parrella (Istituto per la Protezione delle Piante del CNR, Italy) who kindly provided reference Q and B biotypes; Ms J. Joseph (Agricultural Research Organization (ARO), Gilat Research Center, Israel) for her valuable editing of the paper; and H. Bhatt, M. Rippa, S. Kleitman, R. Mori, H. Breslauer and O. Segev (ARO, Israel) for their technical assistance. The authors acknowledge with thanks the Chief Scientist of the Ministry of Agriculture and the Israeli Cotton Board for their partial support of this study.
- DNA markers
- Population dynamics