Includes: Introduction - Synonymy - Distribution - Description and Biology - Hosts - Damage - Management - Selected References
Also available on the Featured Creatures website ...at http://entnemdept.ufl.edu/creatures/veg/Aleurotrachelus_trachoides.htm
The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is among the 100 worst invasive species in the world. As one of the most important crop pests and virus vectors, B. tabaci causes substantial crop ...losses and poses a serious threat to global food security.
We report the 615-Mb high-quality genome sequence of B. tabaci Middle East-Asia Minor 1 (MEAM1), the first genome sequence in the Aleyrodidae family, which contains 15,664 protein-coding genes. The B. tabaci genome is highly divergent from other sequenced hemipteran genomes, sharing no detectable synteny. A number of known detoxification gene families, including cytochrome P450s and UDP-glucuronosyltransferases, are significantly expanded in B. tabaci. Other expanded gene families, including cathepsins, large clusters of tandemly duplicated B. tabaci-specific genes, and phosphatidylethanolamine-binding proteins (PEBPs), were found to be associated with virus acquisition and transmission and/or insecticide resistance, likely contributing to the global invasiveness and efficient virus transmission capacity of B. tabaci. The presence of 142 horizontally transferred genes from bacteria or fungi in the B. tabaci genome, including genes encoding hopanoid/sterol synthesis and xenobiotic detoxification enzymes that are not present in other insects, offers novel insights into the unique biological adaptations of this insect such as polyphagy and insecticide resistance. Interestingly, two adjacent bacterial pantothenate biosynthesis genes, panB and panC, have been co-transferred into B. tabaci and fused into a single gene that has acquired introns during its evolution.
The B. tabaci genome contains numerous genetic novelties, including expansions in gene families associated with insecticide resistance, detoxification and virus transmission, as well as numerous horizontally transferred genes from bacteria and fungi. We believe these novelties likely have shaped B. tabaci as a highly invasive polyphagous crop pest and efficient vector of plant viruses. The genome serves as a reference for resolving the B. tabaci cryptic species complex, understanding fundamental biological novelties, and providing valuable genetic information to assist the development of novel strategies for controlling whiteflies and the viruses they transmit.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Coinfection of cassava with Cassava brown streak disease virus and its Ugandan variant is a threat to cassava production.•Coinfection is highly sensitive to roguing frequency and vector ...mortality.•Temperature variability causes multiple seasonal whitefly generations resulting in multiple epidemics.•Management of nymph development is more important than whitefly fecundity rate for epidemics’ control.
Mixed infections of Cassava brown streak virus (CBSV) and its Ugandan variant (UCBSV) in cassava hosts are increasingly threatening food security in East and Central Africa. The possibility of these viruses spreading to cassava producing countries in West Africa is of great concern. Most epidemiological models developed to address this challenge do not include the possibility of coinfection and whitefly lifecycle in managing these viruses. The question is: how does the inclusion of whitefly lifecycle and temperature variability influence disease outbreak and spread? We develop a host-vector-virus coinfection model that incorporates the whitefly life cycle and temperature variability as drivers of an epidemic. Using a combination of analytical and numerical simulations, we identify the key factors that drive disease outbreaks in cassava plantations. We also demonstrate that management of the whitefly's immature development stage can reduce disease prevalence and crop losses associated with these outbreaks. These results suggest that biological control agents using natural enemies should be given higher priority than the use of insecticides in management strategies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of this note is to report the parasitism of Aleurodicus pseudugesii Martin, 2008 (Hemiptera: Aleyrodidae) nymphs by Aleuroctonus marki Hansson & LaSalle, 2003 (Hymenoptera: Eulophidae) in ...coconut palm Cocos nucifera L. (Arecaceae) in Santa Izabel do Pará, a municipality in the Eastern Amazon. This is the first recorded instance of a parasitoid species in A. pseudugesii.
The phytophagous whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes serious crop yield losses around the world especially by vectoring viruses. Exogenous jasmonic acid (JA) induces ...direct plant resistance to B. tabaci, but the underlying mechanism of JA‐induced exogenous defenses is not well understood. Here, we demonstrate that exogenous JA not only increases the cytosolic Ca2+ concentration (Ca2+cyt) in tomato mesophyll cells but also induces the expression of Ca2+‐sensor genes and plant defense genes. Pre‐treatment with Ca2+ inhibitor (ruthenium red) significantly repressed the elevation of Ca2+cyt, expression of JA‐induced genes, and emission of plant volatiles induced by JA, thus reducing the JA‐induced direct (feeding choice and fitness of B. tabaci) and indirect olfactory choice and parasitism by the parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae) plant resistance to B. tabaci. These results indicate that the Ca2+ signal induced by JA mediates and directs the plants defenses against whitefly. Present results will not only give us a better understanding of how exogenous JA influences the crop community, but also deliver some clues for the potential application of exogenous JA, as a plant elicitor, in whitefly management.
Exogenous jasmonic acid (JA) can induce defenses against the whithefly Bemisia tabaci (Hemiptera: Aleyrodidae) in tomato plants, not only by directly decreasing the attraction and performance of the whitefly, but also by indirectly increasing the attraction and parasitism of the parasitoid wasp Encarsia formosa (Hymenoptera: Aphelinidae). Moreover, a calcium signal induced by JA mediates and orients these plant defenses against whitefly. JA can act as a plant elicitor which enhances the defense against whitefly.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Field occurrence of the exotic neotropical nesting whitefly, Paraleyrodes minei Iaccarino in association with Bondar’s nesting whitefly, Paraleyrodes bondari Peracchi on coconut leaflets is reported ...from Kerala, India. These coconut palms were previously infested by the rugose spiralling whitefly, Aleurodicus rugioperculatus Martin, which was reported from Kerala and Tamil Nadu during 2016. P. minei closely resembles P. bondari, but is devoid of the oblique grey bands on the wings and it constructs loosely woven, woolly wax nests. Female P. minei are white, but males are smoky grey. Cockhead-like male aedeagus with two thin appendixes projected downwards is the unique feature for species-level identification of P. minei. Detection of three non-native whiteflies of neotropical origin infesting coconut palms in India within a span of two years suggests their simultaneous introduction. Invasive potential of P. minei due to its polyphagous nature and short lifecycle calls upon strict policy frameworks in exchange of planting materials. Domestic quarantine should be strictly enforced in the country to avoid spread of this pest to other coconut-growing regions.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The worldwide distribution and extensive genetic diversity of the whitefly,Bemisia tabaci,has long been recognized.However,the levels of separation within B.tabaci and the nomenclature of the various ...genetic groups have been a subject of debate.Recent phylogenetic analyses indicate that B.tabaci is a complex composed of 28 morphologically indistinguishable species.In this article,we first review the debate and difficulties associated with B.tabaci＇s taxonomy and systematics,and argue for the need to apply the biological species concept in order to elucidate B.tabaci＇s systematics.We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B.tabaci.Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs,and observations on mating behaviour have been conducted for seven species pairs.Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species.We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility.Finally,we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B.tabaci groups and propose future research directions on the systematics of this complex.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary
Arginine rich, mutated in early stage of tumours (Armet), is a well‐characterized bifunctional protein as an unfolded protein response component intracellularly and a neurotrophic factor ...extracellularly in mammals. Recently, a new role of Armet as an effector protein mediating insect–plant interactions has been reported; however, its molecular mechanisms underlying the regulation of plant defences remain unclear.
We investigated the molecular mechanisms underlying whitefly‐secreted Armet‐mediated regulation of insect–plant interaction by agrobacterium‐mediated transient expression, RNA interference, electrical penetration graph, protein–protein interaction studies, virus‐induced gene silencing assay, phytohormone analysis and whitefly bioassays.
Armet, secreted by Bemisia tabaci whitefly, is highly expressed in the primary salivary gland and is delivered into tobacco plants during feeding. Overexpression of the BtArmet gene in tobacco enhanced whitefly performance, while silencing the BtArmet gene in whitefly interrupted whitefly feeding and suppressed whitefly performance on tobacco plants. BtArmet was shown to interact with NtCYS6, a cystatin protein essential for tobacco anti‐whitefly resistance, and counteract the negative effects of NtCYS6 on whitefly.
These results indicate that BtArmet is a salivary effector and acts to promote whitefly performance on tobacco plants through binding to the tobacco cystatin NtCYS6. Our findings provide novel insight into whitefly–plant interactions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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