ORCID Profile
0000-0002-7285-2312
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Publisher: Cold Spring Harbor Laboratory
Date: 05-08-2019
DOI: 10.1101/724765
Abstract: Identification of Bemisia tabaci cryptic whitefly species complex currently relies on molecular characterisation of the mitochondrial DNA cytochrome oxidase subunit I (mtCOI) partial gene, however, nuclear mitochondrial sequences (NUMTs), PCR-derived pseudogenes and/or poor sequence editing have hindered this effort. To-date, ca. 5,175 partial (≥ 300bp) mtCOI sequences for species identification purposes have been reported. We reviewed ca. 10% of sequences representing the standard B. tabaci species complex mtCOI dataset. We found that 333 sequences (64.9%) were NUMTs, pseudogenes and/or affected by poor sequence quality. Amino acid pattern analyses of high throughput sequencing-derived mtCOI gene from 24 ‘ tabaci ’ and ‘non- tabaci ’ species enabled differentiation between NUMTs seudogene-affected and likely real mtCOI sequences, and that the SSA4, SSA5/SSA8, AsiaII-2 and AsiaII_4 species were NUMTs seudogenes artefacts. Intra-specific uncorrected nucleotide distances ( p -dist) from our up-dated dataset ranged from 0-1.98%, inter-specific p -dist within phylogenetic clades ranged between ca. 2.5 and 8%, and 8 and % for species between phylogenetic clades. Differentiating between closely related species could therefore utilise an ‘average’ p -dist of 2.5%. Despite the smaller B. tabaci mtCOI dataset, six putative new species were identified. Adoption of our standardised workflow and up-dated mtCOI clean dataset could facilitate better diagnostics of B. tabaci and ‘non- tabaci ’ cryptic species.
Publisher: Springer Science and Business Media LLC
Date: 12-04-2021
DOI: 10.1038/S41598-021-87107-Z
Abstract: The Bemisia cassava whitefly complex includes species that cause severe crop damage through vectoring cassava viruses in eastern Africa. Currently, this whitefly complex is ided into species and subgroups (SG) based on very limited molecular markers that do not allow clear definition of species and population structure. Based on 14,358 genome-wide SNPs from 62 Bemisia cassava whitefly in iduals belonging to sub-Saharan African species (SSA1, SSA2 and SSA4), and using a well-curated mtCOI gene database, we show clear incongruities in previous taxonomic approaches underpinned by effects from pseudogenes. We show that the SSA4 species is nested within SSA2, and that populations of the SSA1 species comprise well-defined south-eastern (Madagascar, Tanzania) and north-western (Nigeria, Democratic Republic of Congo, Burundi) putative sub-species. Signatures of allopatric incipient speciation, and the presence of a ‘hybrid zone’ separating the two putative sub-species were also detected. These findings provide insights into the evolution and molecular ecology of a highly cryptic hemipteran insect complex in African, and allow the systematic use of genomic data to be incorporated in the development of management strategies for this cassava pest.
Publisher: Springer Science and Business Media LLC
Date: 07-04-2022
DOI: 10.1038/S42003-022-03230-1
Abstract: Native to the Americas, the invasive Spodoptera frugiperda (fall armyworm FAW) was reported in West Africa in 2016, followed by its chronological detection across the Old World and the hypothesis of an eastward Asia expansion. We explored population genomic signatures of American and Old World FAW and identified 12 maternal mitochondrial DNA genome lineages across the invasive range. 870 high-quality nuclear single nucleotide polymorphic DNA markers identified five distinct New World population clusters, broadly reflecting FAW native geographical ranges and the absence of host-plant preferences. We identified unique admixed Old World populations, and admixed and non-admixed Asian FAW in iduals, all of which suggested multiple introductions underpinning the pest’s global spread. Directional gene flow from the East into eastern Africa was also detected, in contrast to the west-to-east spread hypothesis. Our study demonstrated the potential of population genomic approaches via international partnership to address global emerging pest threats and biosecurity challenges.
Publisher: Springer Science and Business Media LLC
Date: 05-06-2023
DOI: 10.1038/S41467-023-38988-3
Abstract: Embryonic tissues undergoing shape change draw mechanical input from extraembryonic substrates. In avian eggs, the early blastoderm disk is under the tension of the vitelline membrane (VM). Here we report that the chicken VM characteristically downregulates tension and stiffness to facilitate stage-specific embryo morphogenesis. Experimental relaxation of the VM early in development impairs blastoderm expansion, while maintaining VM tension in later stages resists the convergence of the posterior body causing stalled elongation, failure of neural tube closure, and axis rupture. Biochemical and structural analysis shows that VM weakening is associated with the reduction of outer-layer glycoprotein fibers, which is caused by an increasing albumen pH due to CO 2 release from the egg. Our results identify a previously unrecognized potential cause of body axis defects through mis-regulation of extraembryonic tissue tension.
Publisher: Informa UK Limited
Date: 02-01-2019
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.CBPB.2018.11.001
Abstract: It has been reported that phaseolin, the major storage globulin of the common bean (Phaseolus vulgaris), is toxic to Callosobruchus maculatus larvae, an Old World bruchid beetle that is not capable of infesting this New World edible bean. It has also been demonstrated that vicilin, the major storage globulin found in cowpea (Vigna unguiculata) seeds, is absorbed through receptor-mediated endocytosis in the insect midgut. A putative vicilin receptor has been purified and showed high homology to α-tocopherol transfer protein. However, the ingestion of a variant vicilin purified from C. maculatus resistant seeds inhibits transcytosis, resulting in the accumulation of vicilins in the midgut cells and ultimately antibiosis. In the present work, we studied the cellular up-take of phaseolin in C. maculatus larvae with the aim of discovering if this protein is also capable of inhibiting endocytic traffic in the enterocytes. FITC-labelled vicilin and FITC-labelled phaseolin were incorporated into the diet of the larvae at a physiological concentration of 0.5% w/w. The fate of labelled and non-labelled globulins was monitored by confocal microscopy. Here we demonstrated that phaseolin is also endocytosed by enterocytes causing an accumulation of endocytic vesicles in the midgut when compared to the ingestion of vicilin obtained from a susceptible V. unguiculata cultivar. From the results obtained for HNE, MDA and TBARS, a pro-oxidative scenario was established in the intestinal epithelial cells of the larvae, which may explain the deleterious effect observed in larvae developing inside P. vulgaris seeds.
Publisher: Cold Spring Harbor Laboratory
Date: 12-06-2020
DOI: 10.1101/2020.06.12.147660
Abstract: Native to the Americas, the invasive Spodoptera frugiperda (fall armyworm FAW) was reported in West Africa in 2016, followed by chronological order of detections across the Old World and the hypothesis of an eastward Asia expansion. We explored population genomic signatures of American and Old World FAW and identified 12 maternal mitochondrial DNA genome lineages across the invasive range, while from 870 high-quality nuclear single nucleotide polymorphic DNA markers five distinct New World population clusters were identified, broadly reflected their native geographical ranges and absence of host-plant preferences. We identified unique admixed Old World populations, and admixed and non-admixed Asian FAW in iduals, all of which suggested multiple introductions underpinned the pest’s global spread. Directional gene flow from the East into eastern Africa was also detected, in contrast to the west-to-east spread hypothesis. Our study demonstrated population genomic approaches via international partnership to address global emerging pest threats and biosecurity challenges.
Publisher: Informa UK Limited
Date: 02-01-2019
Publisher: Cold Spring Harbor Laboratory
Date: 25-02-2021
DOI: 10.1101/2021.02.24.432525
Abstract: Embryonic tissues undergoing shape change draw mechanical input from extraembryonic substrates. In avian eggs, the early blastoderm disk is under the tension of the vitelline membrane (VM). Here we report that the chicken VM characteristically downregulates tension and stiffness to facilitate stage-specific embryo morphogenesis. Experimental relaxation of the VM early in development impairs blastoderm expansion, while maintaining VM tension in later stages resists the convergence of the posterior body causing stalled elongation, failure of neural tube closure, and axis rupture. Biochemical and structural analysis shows that VM weakening is associated with the reduction of outer-layer glycoprotein fibers, which is caused by an increasing albumen pH due to CO 2 release from the egg. Our results identify a previously unrecognized potential cause of body axis defects through mis-regulation of extraembryonic tissue tension.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daniele Kunz.