Molecular Characterization ofBemisia tabaciPopulations in Tunisia: Genetic Structure and Evidence for Multiple Acquisition of Secondary Symbionts

Abstract

A survey was conducted during 2009-2010 seasons to identify the distribution of Bemisia tabaci (Gennadius) biotypes in Tunisia. The genetic affiliation of collected populations was determined by polymerase chain reaction (PCR)-restriction fragment-length polymorphism (TaqI) of the mitochondrial cytochrom oxidase I (mtCOI) gene. Results, validated by sequencing and phylogenetic analysis, allowed the clustering of sampled sweetpotato whiteflies into B and Q biotypes. As B. tabaci harbors the obligatory bacterium Portiera aleyrodidarum, and a diverse array of secondary symbionts including Rickettsia, Hamiltonella, Wolbachia, Cardinium, Arsenophonus, and Fritschea, we report here the infectious status of Tunisian populations by secondary symbionts to find out a correlation between bacterial composition to biotype. The genetic variability and structure of B. tabaci populations in Tunisia was driven by analysis of molecular variance (AMOVA) and the hypothesis of isolation by distance was explored. Selective neutrality and genetic haplotype network tests suggested that Tunisian sweetpotato whiteflies have been undergoing a potential expansion followed by gene flow restriction.

Evaluation of tomato entries with different combinations of resistance genes to tomato yellow leaf curl disease in Tunisia

“…Moreover, in the absence of effective control methods, the virus had spread readily and Tunisian tomato production had been extensively damaged by TYLCD since the end of the 1990s (Gorsane et al. ). In 2012, the whole tomato late season crop in Nadhour (Zaghouan region, Tunisia) was entirely lost because of TYLCD damage.…”

“…Two coexisting B. tabaci species, Middle East‐Asia Minor I (MEAMI) (formerly biotype B) and the Mediterranean (Med) species (formerly biotype Q) (Gorsane et al. , Saleh et al. , Laarif et al.…”

Quantification and Localization of Watermelon Chlorotic Stunt Virus and Tomato Yellow Leaf Curl Virus (Geminiviridae) in Populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with Differential Virus Transmission Characteristics

“…Secondary bacterial endosymbionts are abundant in many insects and those can provide additional features for the host [38]. Besides the obligatory bacterial endosymbiont Portiera aleyrodidarum [39] Rickettsia , Hamiltonella , Wolbachia , Arsenophonus , Cardinium and Fritschea are described for B. tabaci [32], [40], [41] which can occur singly or in mixed communities with others [32], [42]–[44]. Recently, additional Enterobacter , Bacillus , Paracoccus, Acinetobacter and an Orientia- like organism were found sporadically in whiteflies [45], [46].…”

Mitochondrial, nuclear, and endosymbiotic diversity of two recently introduced populations of the invasive Bemisia tabaci MED species in La Réunion

“…Indeed, individuals analysed from the western MED subgroup were infected with Hamiltonella and/or Cardinium, and the individuals belonging to the eastern MED subgroup were coinfected with Rickettsia and Wolbachia , sometimes together with Arsenophonus . Previous studies assessed the endosymbiont diversity of MED species in Chinese (Chu et al ., ), Tunisian (Gorsane et al ., ), Israeli (Chiel et al ., ), and Croatian (Skaljac et al ., ) populations and revealed heterogeneous assemblages but did not specify associated subgroups. The subgroup specification found in our study is in accordance with Gueguen et al .…”