Bemisia tabaci Sub-Saharan Africa 2

Whiteflies of the Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) species complex are phloem-feeding insects and plant-virus vectors, some of which are widely regarded to be amongst the world’s worst agricultural pests. Outbreaks of B. tabaci cause significant crop losses and contribute to global food insecurity.

To date, at least six putative cryptic species of B. tabaci have been reported to colonise cassava (Manihot esculenta) in sub-Saharan Africa (SSA) and these were named serially from SSA1 (and its subgroups) to SSA5 [1-5]. Of these, SSA1 (and its subgroups) and SSA2 have been reported as the prevalent whiteflies associated with the spread of viruses that cause devastating cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) pandemics [6-8].

Populations of B. tabaci SSA2 have been recorded from the eastern, southern, central and western areas of Africa as well as in the south of Spain [5,9-11]. In the 1990s, B. tabaci SSA2 was hypothesised to be an invasive species associated with the CMD pandemic in Uganda [8]. More recently, however, B. tabaci SSA2 has rarely been found in Uganda and the superabundant populations have been identified as the species B. tabaci SSA1-SG1 [3, 8, 12,13].

The genome described here was generated from a Nigerian population of B. tabaci SSA2, that was inbred in the laboratory to reduce heterozygosity.

The Bemisia tabaci cryptic species complex

Members of the B. tabaci species complex cause plant damage by feeding on plant-phloem sap, inducing phytotoxic disorders, depositing honeydew on which sooty moulds develop and by vectoring > 300 plant-virus species in the genera Begomovirus, Carlavirus, Crinivirus, Ipomovirus, Polerovirus and Torradovirus [14,15]. Diseases caused by these viruses often spread rapidly with devastating yield losses of up to 100% [6].

Bemisia tabaci sensu lato currently represents a relatively large group (>44) of mostly unresolved cryptic species, as inferred from phylogenetic species delimitation studies [2,16]. These morphologically indistinguishable species differ from one another not only in their genetic relatedness, but also in various biological traits such as plant host-range breadth, fecundity, insecticide resistance, and plant-virus transmission efficiencies.

Bemisia tabaci sensu lato are distributed globally, from tropical to temperate climatic zones and across all continents (except Antarctica) [2]. Most cryptic species in this complex, as currently understood, are geographically restricted, but two of them are highly invasive globally i.e., B. tabaci Middle East-Asia Minor 1 (MEAM1, also referred to as biotype B and Bemisia argentifolii) and B. tabaci Mediterranean (MED, also referred to as biotype Q) [2]. Bemisia tabaci sensu lato live predominantly on herbaceous plant hosts and have been recorded from an exceedingly broad range of host plants (>500 species) [17]. The documented host-plant range of most cryptic species within the complex remains largely incomplete.

Picture credit: Sharon van Brunschot.

Taxonomy ID 7038

Data source Ensembl Metazoa

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