Mohamed Makni - Academia.edu (original) (raw)

Papers by Mohamed Makni

Journal of General Virology, 1996

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major in... more The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major invasive pest of citrus in Tunisia. In order to help the implementation of an efficient integrated management strategy, it was essential to assess the genetic diversity and population structure of the pest. For this purpose, random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was applied, using eight oligo-nucleotide primers, to reveal genetic variability among eight populations of P. citrella, originating from the north, center and south of Tunisia. A total of 66 RAPD markers and 33 phenotypes were generated. Inter-population polymorphism was revealed, using the percentage of polymorphic markers (62.12 %), mean number of phenotypes generated per primer (4.125) and mean genetic distance (0.199). Hierarchical analysis, using the UPGMA method, indicated that the genetic variability was influenced by the regional distribution. This pattern of population clustering was suppor...

Journal of Crop Protection, 2012

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major in... more The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major invasive pest of citrus in Tunisia. In order to help the implementation of an efficient integrated management strategy, it was essential to assess the genetic diversity and population structure of the pest. For this purpose, random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was applied, using eight oligo-nucleotide primers, to reveal genetic variability among eight populations of P. citrella, originating from the north, center and south of Tunisia. A total of 66 RAPD markers and 33 phenotypes were generated. Inter-population polymorphism was revealed, using the percentage of polymorphic markers (62.12 %), mean number of phenotypes generated per primer (4.125) and mean genetic distance (0.199). Hierarchical analysis, using the UPGMA method, indicated that the genetic variability was influenced by the regional distribution. This pattern of population clustering was suppor...

The green citrus aphid, Aphis spiraecola Patch, is an important pest attacking many plant species... more The green citrus aphid, Aphis spiraecola Patch, is an important pest attacking many plant species, including citrus. We have analyzed the genetic variability among green citrus aphid adults sampled from six citrus cultivars grown in Algeria (an orange, a grapefruit, a lemon and three mandarin cultivars), using the random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) technique. Analysis of molecular variance (AMOVA), based on RAPD markers, indicated a significant difference between the studied samples, correlated to the host plant species, while host cultivar and geographical origin had no significant impact on the genetic diversity. Two-dimensional PCO analysis confirmed AMOVA results, showing the grouping of the different insects into four major clusters according to their host plant species. The Neighbor-Joining dendrogram constructed based on the Euclidian distance grouped the accessions into four main clusters according to their host plant species genotypes, giv...

BMC Biology, 2020

Background Although native to North America, the invasion of the aphid-like grape phylloxera Dakt... more Background Although native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors such as pathogens and climate change. Limited understanding of the insect genetics resulted in successive outbreaks across the globe when rootstocks failed. Here we report the 294-Mb genome of D. vitifoliae as a basic tool to understand host plant manipulation, nutritional endosymbiosis, and enhance global viticulture. Results Using a combination of genome, RNA, and population resequencing, we found grape phylloxera showed high duplication rates since its common ancestor with aphids, but similarity in most metabolic genes, despite lacking obligate nutritional symbioses and feeding from parenchyma. Similarly, no enrichment occurred in developme...

European Journal of Entomology, 2017

http://www.eje.cz "cut and paste" model. Each of these classes is subdivided into subclasses, sup... more http://www.eje.cz "cut and paste" model. Each of these classes is subdivided into subclasses, superfamilies, families and subfamilies (Wicker et al., 2007; Piégu et al., 2015; Arensburger et al., 2016). Mariner-like elements (MLEs) are Class II transposons belonging to the large IS630-Tc1-mariner superfamily i.e. ITm (Plasterk, 1996; Plasterk et al., 1999) and known to be widespread in most eukaryotic organisms including insects (Robertson, 1993).They are subdivided into fi ve major subfamilies based on their sequence similarities and phylogenetic relationships: mauritiana, cecropia, mellifera/capitata, elegans/briggsae and irritans (Robertson & MacLeod, 1993; Bigot et al., 2005). The latter subfamily is characterized, at least, by four major characteristic lineages. The fi rst lineage corresponds to the Hsmar2-like elements in chordates and primates, the second contains

Genome Biology and Evolution, 2017

The piggyBac transposable element was originally isolated from the cabbage looper moth, Trichoplu... more The piggyBac transposable element was originally isolated from the cabbage looper moth, Trichoplusia ni, in the 1980s. Despite its early discovery and specificity compared to the other Class II elements, the diversity and evolution of this superfamily have been only partially analyzed. Two main types of elements can be distinguished: the piggyBac-like elements (PBLE) with terminal inverted repeats, untranslated region, and an open reading frame encoding a transposase, and the piggyBac-derived sequences (PGBD), containing a sequence derived from a piggyBac transposase, and which correspond to domesticated elements. To define the distribution, their structural diversity and phylogenetic relationships, analyses were conducted using known PBLE and PGBD sequences to scan databases. From this data mining, numerous new sequences were characterized (50 for PBLE and 396 for PGBD). Structural analyses suggest that four groups of PBLE can be defined according to the presence/absence of sub-terminal repeats. The transposase is characterized by highly variable catalytic domain and C-terminal region. There is no relationship between the structural groups and the phylogeny of these PBLE elements. The PGBD are clearly structured into nine main groups. A new group of domesticated elements is suspected in Neopterygii and the remaining eight previously described elements have been investigated in more detail. In all cases, these sequences are no longer transposable elements, the catalytic domain of the ancestral transposase is not always conserved, but they are under strong purifying selection. The phylogeny of both PBLE and PGBD suggests multiple and independent domestication events of PGBD from different PBLE ancestors.

Brazilian Archives of Biology and Technology, 2016

Computational investigation of a set of publicly available plant microRNAs revealed 19 barley-and... more Computational investigation of a set of publicly available plant microRNAs revealed 19 barley-and other plantsencoded miRNAs and their near-complement reverse sequences (miRNA *) that have potential to bind all B/CYDV open reading frames (ORFs) except ORF0 and ORF6. These miRNAs/miRNAs * , their binding positions and targets are discussed in the context of biological protection of cereals against B/CYDV, based on antiviral silencing.

Revista colombiana de entomología

We report information about the structure of the karyotype of M. hordei, a fly that infests barle... more We report information about the structure of the karyotype of M. hordei, a fly that infests barley in the south of Tunisia. The number of chromosomes was found to be (2n = 8) in somatic female cells and (2n-2 = 6) in somatic male cells, which is similar to the karyotype of M.destructor. Mitotic and polytene chromosomes of M. hordei are described and compared with those of M. destructor. The karyological data are discussed in terms of genetic mechanisms underlying divergence of M. hordei and M. destructor.

Journal of the Entomological Research Society

The giant black aphid Pterochloroides persicae (Cholodkovsky) is one of the most damaging pests o... more The giant black aphid Pterochloroides persicae (Cholodkovsky) is one of the most damaging pests of Prunaceous trees. It has been reported in North Africa since 1987. In this study, we have used sequences of the mitochondrial cytochrome b gene (Cytb), to elaborate the first phylogenetic analysis of this polyphagous pest. Sequences were obtained from 34 Tunisian clones covering different locations and different host plants. A total of 25 haplotypes were identified, among which 21 were unique. Haplotype H7 that was the most frequent would be the ancestral one. The maximum likelihood phylogenetic tree revealed that clones originating from distinct locations clustered into a single consistent group with little variations, reflecting the loss of genetic diversity that would have followed introduction of this pest. These results will have important implications for future studies of the genetic structure of this pest and other closely-related species.

Journal of the Entomological Research Society

The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. Based on host pl... more The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. Based on host plant response to infestation, several biotypes of this pest have been identified and their phylogenetic relationships inferred using the mitochondrial COI gene. In this study, we have sequenced a fragment of 572 bp of COI gene from 10 S. graminum clones collected, over a three-year period, from 4 sites located in the north and south of Tunisia. Alignment of these sequences revealed the presence of 3 distinct haplotypes, that clustered with the agricultural biotypes I, J, E, K and C. Therefore, we suggest that resistance genes Gb3, Gb4, Gb5 and Gb6 in wheat should be the first choice for use in wheat improvement programs, for resistance against greenbug, in Tunisia.

The whitefly, Bemisia tabaci Gennadius, is one of the most damaging pests in agricultural systems... more The whitefly, Bemisia tabaci Gennadius, is one of the most damaging pests in agricultural systems worldwide. Knowledge of the genetic structure of this species is crucial for efficient management. In this study, we have used Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPDPCR) to assess the genetic diversity and analyze the genetic structure of this insect pest. Using 120 insect samples, a total of 150 polymorphic markers were revealed. The genetic structure was analyzed, based on the molecular variance (AMOVA), genetic distances (Fst) and multidimensional scaling (MDS). AMOVA revealed that diversity between geographical domains (North vs. South) and between individuals within populations were the most determining factors in the partitioning of the total genetic diversity (50.19% and 44.85%, respectively). In addition, Fst and MDS indicated that the populations of B. tabaci were structured according to their geographical origin. These results strongly suggest that ec...

Romanian agricultural research

The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. In this research... more The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. In this research, 14 Tunisian bread wheat genotypes were evaluated for resistance to S. graminum. Eight cultivars were scored as susceptible with an average injury level varying between 7.7 and 9. Three cultivars were moderately resistant (4.0 -6.0) and three expressed high levels of resistance (1.2 -2.0). A previously described SSR marker (Xwmc634) cosegregating with the Gb3 greenbug resistance gene in wheat was identified in 'Ariana 66' cultivar, suggesting the presence of Gb3 in this cultivar. Based on these results, we conclude that 'Ariana 66' should be incorporated in wheat breeding programs for resistance against greenbug, in Tunisia, as a local adapted source of Gb3. Additionally, cultivars 'Soltane 73' and 'EAP63A', which expressed high levels of resistance and did not express the SSR marker associated with Gb3, could be taken into consideration for diversifying ...

Revista colombiana de entomología

The greenbug Schizaphis graminum, is a major pest of wheat worldwide. Biotype screening of this p... more The greenbug Schizaphis graminum, is a major pest of wheat worldwide. Biotype screening of this pest is essential to develop pest management programs. In this research, eight greenbug clones, collected on wheat in the cereal-growing region of Béja (north Tunisia), were used to determine their damage on six reference wheat cultivars. All tested clones shared a unique biotypic profile, similar to biotype C. Moreover, DNA from the tested clones and that from seven reference clones of biotypes C, E, F, G, H, I and K, was analyzed, using 5 RAPD-PCR primers. The UPGMA method clustered samples into two distinct clades: a first one (I) included clones from north Tunisia, which were clearly associated to agricultural biotypes C, E, I and K, while a second clade (II) included non agricultural biotypes F, G and H. Results reported in this paper suggest that resistance genes Gb2, Gb3, Gb4, Gb5 and Gb6 in wheat would be the most efficient if used in wheat improvement programs for resistance agai...

Romanian agricultural research

Aphis fabae is a common polyphagous aphid represented by a complex of heteroecious holocyclic sub... more Aphis fabae is a common polyphagous aphid represented by a complex of heteroecious holocyclic subspecies, using a wide range of secondary host plant species. In this study, we used Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) to assess the genetic diversity and analyse the genetic structure of three subspecies from this complex, namely A. f. fabae, A. f. solanella and A. f. cirsiiacanthoidis, collected from 4 locations in the North and South of Tunisia. Using 108 aphid samples, a total of 96 polymorphic markers and 81 RAPD phenotypes were revealed, showing variation between subspecies, locations and primers. The presence of overlapping RAPD phenotypes was detected between subspecies, locations and samples within each location. The genetic structure was analysed, based on molecular variance (AMOVA), genetic distances (Fst), multidimensional scaling (MDS) and cluster analysis (UPGMA). AMOVA revealed that diversity among locations within each subspecies was t...

Acta virologica, 2014

Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to ... more Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to characterize the B/CYDV isolates occurring in Tunisia, 240 barley leaves were randomly sampled from 6 fields following a North-South trend and analyzed by serological and molecular tests. DAS-ELISA results showed 40 positive samples with a prevalence of barley yellow dwarf virus (BYDV)-PAV (77.5%), followed by cereal yellow dwarf virus (CYDV)-RPV (25%) and BYDV-MAV (15%). Studies of the geographic distribution showed a high incidence of B/CYDV in the Tunisian Southern provinces. RT-PCR assays were performed to amplify the viral coat protein gene (CP) and sequence analyses revealed six BYDV-PAV haplotypes named PAV-TN1 to PAV-TN6. Phylogenetic analysis showed that the six Tunisian haplotypes were close to BYDV-PAV-II subspecies and had a strong similarity with Moroccan, Czech, French and German haplotypes. Although PAV-TN2 and PAV-TN5 showed up to 10% divergence from BYDV-PAV-II at the amino acid level, it seems to belong to the same subspecies but in a separated cluster. Our results will be important in developing appropriate control measures against BYDV disease in Tunisia.

Molecular Genetics and Genomics, 2014

complete gene models, 464 were longer than 200 aa, among them 436 had less than 70 % of sequence ... more complete gene models, 464 were longer than 200 aa, among them 436 had less than 70 % of sequence identity to each other. This gene models set was deeply characterized. (1) First, we have analyzed domain architecture and identified, in addition to typical domain combinations, the presence of particular domains like signal peptides, zinc fingers, kinases, heavy-metal-associated and WRKY DNA-binding domains. (2) Functional and expression annotation via homology searches in protein and transcript databases, based on sufficient criteria, enabled identifying similar proteins for 60 % of the studied gene models and expression evidence for 13 % of them. (3) Shared orthologous groups were defined using NBS-domain proteins of rice and Brachypodium distachyon. (4) Finally, alignment of the 436 NBS-containing gene models to the full set of scaffolds from the IWGSC's wheat chromosome survey sequence enabled high-stringence anchoring to chromosome arms. The distribution of the R genes was found balanced on the three wheat sub-genomes. In contrast, at chromosome scale, 50 % of members of this gene family were localized on 6 of the 21 wheat chromosomes and ~22 % of them were localized on homeologous group 7. The results of this study provide a detailed analysis of the largest family of plant disease resistance genes in allohexaploid wheat. Some structural traits reported had not been previously identified and the genome-derived data were confronted with those stored in databases outlining the functional specialization of members of this family. The large reservoir of NBS-type genes presented and discussed will, firstly, form an important framework for marker-assisted improvement of resistance in wheat, and, secondly, open up new perspectives for a better understanding of the evolution dynamics of this gene family in grass species and in polyploid systems.

Genetica, 2015

Mariner-like elements (MLEs) are Class II transposons present in all eukaryotic genomes in which ... more Mariner-like elements (MLEs) are Class II transposons present in all eukaryotic genomes in which MLEs have been searched for. This article reports the detection of MLEs in seven of the main fruit tree aphid species out of eight species studied. Deleted MLE sequences of 916-919 bp were characterized, using the terminal-inverted repeats (TIRs) of mariner elements belonging to the mauritiana Subfamily as primers. All the sequences detected were deleted copies of full-length elements that included the 3 0-and 5 0-TIRs but displayed internal deletions affecting Mos1 activity. Networks based on the mtDNA cytochrome oxidase subunit-I (CO-I) and MLE sequences were incongruent, suggesting that mutations in transposon sequences had accumulated before speciation of tree aphid species occurred, and that they have been maintained in this species via vertical transmissions. This is the first evidence of the widespread occurrence of MLEs in aphids.

Pest Management Science, 2012

BACKROUND: The melon fruit fly Bactrocera cucurbitae and the peach fruit fly Bactrocera zonata ar... more BACKROUND: The melon fruit fly Bactrocera cucurbitae and the peach fruit fly Bactrocera zonata are serious pests, native to Asia, that have recently invaded Egypt. In Tunisia, no report of these species has yet been made, but pest risk data suggest that both Bactrocera species are likely to establish in other countries of the Mediterranean region. RESULTS: A quick method, based on a PCR-RFLP of the mitochondrial COI gene, has been developed to enhance species identification for quarantine purposes. The restriction enzymes DdeI and XmnI were used to digest COI PCR products, enabling a rapid diagnosis of B. cucurbitae and B. zonata and their distinction from Tunisia's most devastating fruit pest, Ceratitis capitata. CONCLUSION: The simplicity and relatively low cost of this molecular approach will replace the need to rear immature stages through to adults for identification and will facilitate rapid quarantine decisions providing greater plant protection.

Molecular Genetics and Genomics, 2014

second step, sequences were used as initial seeds to walk up and downstream the nBS domain. This ... more second step, sequences were used as initial seeds to walk up and downstream the nBS domain. This procedure enabled identifying 8 loci ranging in size between 2,115 and 7,653 bp. Ab initio gene prediction identified 8 gene models, among which two had complete OrFs. While Gen-Bank survey confirmed the belonging of sequences to two groups, subsequent characterization using IWGSC genomic and proteomic data showed that the 8 gene models, reported in this study, were unique and their loci matched scaffolds on chromosome arms 1aS, 1BS, 4BS and 1DS. The gene model located on 1DS is a pseudo-Lr21 that was shown to have an nBS-lrr domain structure, while the potential association of the rGas, here reported, is discussed. This study has produced novel R-gene-like loci and models in the wheat genome and provides the first steps toward further elucidation of their role in wheat disease resistance.

Journal of General Virology, 1996

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major in... more The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major invasive pest of citrus in Tunisia. In order to help the implementation of an efficient integrated management strategy, it was essential to assess the genetic diversity and population structure of the pest. For this purpose, random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was applied, using eight oligo-nucleotide primers, to reveal genetic variability among eight populations of P. citrella, originating from the north, center and south of Tunisia. A total of 66 RAPD markers and 33 phenotypes were generated. Inter-population polymorphism was revealed, using the percentage of polymorphic markers (62.12 %), mean number of phenotypes generated per primer (4.125) and mean genetic distance (0.199). Hierarchical analysis, using the UPGMA method, indicated that the genetic variability was influenced by the regional distribution. This pattern of population clustering was suppor...

Journal of Crop Protection, 2012

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major in... more The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a major invasive pest of citrus in Tunisia. In order to help the implementation of an efficient integrated management strategy, it was essential to assess the genetic diversity and population structure of the pest. For this purpose, random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was applied, using eight oligo-nucleotide primers, to reveal genetic variability among eight populations of P. citrella, originating from the north, center and south of Tunisia. A total of 66 RAPD markers and 33 phenotypes were generated. Inter-population polymorphism was revealed, using the percentage of polymorphic markers (62.12 %), mean number of phenotypes generated per primer (4.125) and mean genetic distance (0.199). Hierarchical analysis, using the UPGMA method, indicated that the genetic variability was influenced by the regional distribution. This pattern of population clustering was suppor...

The green citrus aphid, Aphis spiraecola Patch, is an important pest attacking many plant species... more The green citrus aphid, Aphis spiraecola Patch, is an important pest attacking many plant species, including citrus. We have analyzed the genetic variability among green citrus aphid adults sampled from six citrus cultivars grown in Algeria (an orange, a grapefruit, a lemon and three mandarin cultivars), using the random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) technique. Analysis of molecular variance (AMOVA), based on RAPD markers, indicated a significant difference between the studied samples, correlated to the host plant species, while host cultivar and geographical origin had no significant impact on the genetic diversity. Two-dimensional PCO analysis confirmed AMOVA results, showing the grouping of the different insects into four major clusters according to their host plant species. The Neighbor-Joining dendrogram constructed based on the Euclidian distance grouped the accessions into four main clusters according to their host plant species genotypes, giv...

BMC Biology, 2020

Background Although native to North America, the invasion of the aphid-like grape phylloxera Dakt... more Background Although native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors such as pathogens and climate change. Limited understanding of the insect genetics resulted in successive outbreaks across the globe when rootstocks failed. Here we report the 294-Mb genome of D. vitifoliae as a basic tool to understand host plant manipulation, nutritional endosymbiosis, and enhance global viticulture. Results Using a combination of genome, RNA, and population resequencing, we found grape phylloxera showed high duplication rates since its common ancestor with aphids, but similarity in most metabolic genes, despite lacking obligate nutritional symbioses and feeding from parenchyma. Similarly, no enrichment occurred in developme...

European Journal of Entomology, 2017

http://www.eje.cz "cut and paste" model. Each of these classes is subdivided into subclasses, sup... more http://www.eje.cz "cut and paste" model. Each of these classes is subdivided into subclasses, superfamilies, families and subfamilies (Wicker et al., 2007; Piégu et al., 2015; Arensburger et al., 2016). Mariner-like elements (MLEs) are Class II transposons belonging to the large IS630-Tc1-mariner superfamily i.e. ITm (Plasterk, 1996; Plasterk et al., 1999) and known to be widespread in most eukaryotic organisms including insects (Robertson, 1993).They are subdivided into fi ve major subfamilies based on their sequence similarities and phylogenetic relationships: mauritiana, cecropia, mellifera/capitata, elegans/briggsae and irritans (Robertson & MacLeod, 1993; Bigot et al., 2005). The latter subfamily is characterized, at least, by four major characteristic lineages. The fi rst lineage corresponds to the Hsmar2-like elements in chordates and primates, the second contains

Genome Biology and Evolution, 2017

The piggyBac transposable element was originally isolated from the cabbage looper moth, Trichoplu... more The piggyBac transposable element was originally isolated from the cabbage looper moth, Trichoplusia ni, in the 1980s. Despite its early discovery and specificity compared to the other Class II elements, the diversity and evolution of this superfamily have been only partially analyzed. Two main types of elements can be distinguished: the piggyBac-like elements (PBLE) with terminal inverted repeats, untranslated region, and an open reading frame encoding a transposase, and the piggyBac-derived sequences (PGBD), containing a sequence derived from a piggyBac transposase, and which correspond to domesticated elements. To define the distribution, their structural diversity and phylogenetic relationships, analyses were conducted using known PBLE and PGBD sequences to scan databases. From this data mining, numerous new sequences were characterized (50 for PBLE and 396 for PGBD). Structural analyses suggest that four groups of PBLE can be defined according to the presence/absence of sub-terminal repeats. The transposase is characterized by highly variable catalytic domain and C-terminal region. There is no relationship between the structural groups and the phylogeny of these PBLE elements. The PGBD are clearly structured into nine main groups. A new group of domesticated elements is suspected in Neopterygii and the remaining eight previously described elements have been investigated in more detail. In all cases, these sequences are no longer transposable elements, the catalytic domain of the ancestral transposase is not always conserved, but they are under strong purifying selection. The phylogeny of both PBLE and PGBD suggests multiple and independent domestication events of PGBD from different PBLE ancestors.

Brazilian Archives of Biology and Technology, 2016

Computational investigation of a set of publicly available plant microRNAs revealed 19 barley-and... more Computational investigation of a set of publicly available plant microRNAs revealed 19 barley-and other plantsencoded miRNAs and their near-complement reverse sequences (miRNA *) that have potential to bind all B/CYDV open reading frames (ORFs) except ORF0 and ORF6. These miRNAs/miRNAs * , their binding positions and targets are discussed in the context of biological protection of cereals against B/CYDV, based on antiviral silencing.

Revista colombiana de entomología

We report information about the structure of the karyotype of M. hordei, a fly that infests barle... more We report information about the structure of the karyotype of M. hordei, a fly that infests barley in the south of Tunisia. The number of chromosomes was found to be (2n = 8) in somatic female cells and (2n-2 = 6) in somatic male cells, which is similar to the karyotype of M.destructor. Mitotic and polytene chromosomes of M. hordei are described and compared with those of M. destructor. The karyological data are discussed in terms of genetic mechanisms underlying divergence of M. hordei and M. destructor.

Journal of the Entomological Research Society

The giant black aphid Pterochloroides persicae (Cholodkovsky) is one of the most damaging pests o... more The giant black aphid Pterochloroides persicae (Cholodkovsky) is one of the most damaging pests of Prunaceous trees. It has been reported in North Africa since 1987. In this study, we have used sequences of the mitochondrial cytochrome b gene (Cytb), to elaborate the first phylogenetic analysis of this polyphagous pest. Sequences were obtained from 34 Tunisian clones covering different locations and different host plants. A total of 25 haplotypes were identified, among which 21 were unique. Haplotype H7 that was the most frequent would be the ancestral one. The maximum likelihood phylogenetic tree revealed that clones originating from distinct locations clustered into a single consistent group with little variations, reflecting the loss of genetic diversity that would have followed introduction of this pest. These results will have important implications for future studies of the genetic structure of this pest and other closely-related species.

Journal of the Entomological Research Society

The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. Based on host pl... more The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. Based on host plant response to infestation, several biotypes of this pest have been identified and their phylogenetic relationships inferred using the mitochondrial COI gene. In this study, we have sequenced a fragment of 572 bp of COI gene from 10 S. graminum clones collected, over a three-year period, from 4 sites located in the north and south of Tunisia. Alignment of these sequences revealed the presence of 3 distinct haplotypes, that clustered with the agricultural biotypes I, J, E, K and C. Therefore, we suggest that resistance genes Gb3, Gb4, Gb5 and Gb6 in wheat should be the first choice for use in wheat improvement programs, for resistance against greenbug, in Tunisia.

The whitefly, Bemisia tabaci Gennadius, is one of the most damaging pests in agricultural systems... more The whitefly, Bemisia tabaci Gennadius, is one of the most damaging pests in agricultural systems worldwide. Knowledge of the genetic structure of this species is crucial for efficient management. In this study, we have used Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPDPCR) to assess the genetic diversity and analyze the genetic structure of this insect pest. Using 120 insect samples, a total of 150 polymorphic markers were revealed. The genetic structure was analyzed, based on the molecular variance (AMOVA), genetic distances (Fst) and multidimensional scaling (MDS). AMOVA revealed that diversity between geographical domains (North vs. South) and between individuals within populations were the most determining factors in the partitioning of the total genetic diversity (50.19% and 44.85%, respectively). In addition, Fst and MDS indicated that the populations of B. tabaci were structured according to their geographical origin. These results strongly suggest that ec...

Romanian agricultural research

The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. In this research... more The greenbug, Schizaphis graminum (Rondani), is a major pest of wheat worldwide. In this research, 14 Tunisian bread wheat genotypes were evaluated for resistance to S. graminum. Eight cultivars were scored as susceptible with an average injury level varying between 7.7 and 9. Three cultivars were moderately resistant (4.0 -6.0) and three expressed high levels of resistance (1.2 -2.0). A previously described SSR marker (Xwmc634) cosegregating with the Gb3 greenbug resistance gene in wheat was identified in 'Ariana 66' cultivar, suggesting the presence of Gb3 in this cultivar. Based on these results, we conclude that 'Ariana 66' should be incorporated in wheat breeding programs for resistance against greenbug, in Tunisia, as a local adapted source of Gb3. Additionally, cultivars 'Soltane 73' and 'EAP63A', which expressed high levels of resistance and did not express the SSR marker associated with Gb3, could be taken into consideration for diversifying ...

Revista colombiana de entomología

The greenbug Schizaphis graminum, is a major pest of wheat worldwide. Biotype screening of this p... more The greenbug Schizaphis graminum, is a major pest of wheat worldwide. Biotype screening of this pest is essential to develop pest management programs. In this research, eight greenbug clones, collected on wheat in the cereal-growing region of Béja (north Tunisia), were used to determine their damage on six reference wheat cultivars. All tested clones shared a unique biotypic profile, similar to biotype C. Moreover, DNA from the tested clones and that from seven reference clones of biotypes C, E, F, G, H, I and K, was analyzed, using 5 RAPD-PCR primers. The UPGMA method clustered samples into two distinct clades: a first one (I) included clones from north Tunisia, which were clearly associated to agricultural biotypes C, E, I and K, while a second clade (II) included non agricultural biotypes F, G and H. Results reported in this paper suggest that resistance genes Gb2, Gb3, Gb4, Gb5 and Gb6 in wheat would be the most efficient if used in wheat improvement programs for resistance agai...

Romanian agricultural research

Aphis fabae is a common polyphagous aphid represented by a complex of heteroecious holocyclic sub... more Aphis fabae is a common polyphagous aphid represented by a complex of heteroecious holocyclic subspecies, using a wide range of secondary host plant species. In this study, we used Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) to assess the genetic diversity and analyse the genetic structure of three subspecies from this complex, namely A. f. fabae, A. f. solanella and A. f. cirsiiacanthoidis, collected from 4 locations in the North and South of Tunisia. Using 108 aphid samples, a total of 96 polymorphic markers and 81 RAPD phenotypes were revealed, showing variation between subspecies, locations and primers. The presence of overlapping RAPD phenotypes was detected between subspecies, locations and samples within each location. The genetic structure was analysed, based on molecular variance (AMOVA), genetic distances (Fst), multidimensional scaling (MDS) and cluster analysis (UPGMA). AMOVA revealed that diversity among locations within each subspecies was t...

Acta virologica, 2014

Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to ... more Barley yellow dwarf disease is a worldwide ubiquitous virus disease of cereal crops. In order to characterize the B/CYDV isolates occurring in Tunisia, 240 barley leaves were randomly sampled from 6 fields following a North-South trend and analyzed by serological and molecular tests. DAS-ELISA results showed 40 positive samples with a prevalence of barley yellow dwarf virus (BYDV)-PAV (77.5%), followed by cereal yellow dwarf virus (CYDV)-RPV (25%) and BYDV-MAV (15%). Studies of the geographic distribution showed a high incidence of B/CYDV in the Tunisian Southern provinces. RT-PCR assays were performed to amplify the viral coat protein gene (CP) and sequence analyses revealed six BYDV-PAV haplotypes named PAV-TN1 to PAV-TN6. Phylogenetic analysis showed that the six Tunisian haplotypes were close to BYDV-PAV-II subspecies and had a strong similarity with Moroccan, Czech, French and German haplotypes. Although PAV-TN2 and PAV-TN5 showed up to 10% divergence from BYDV-PAV-II at the amino acid level, it seems to belong to the same subspecies but in a separated cluster. Our results will be important in developing appropriate control measures against BYDV disease in Tunisia.

Molecular Genetics and Genomics, 2014

complete gene models, 464 were longer than 200 aa, among them 436 had less than 70 % of sequence ... more complete gene models, 464 were longer than 200 aa, among them 436 had less than 70 % of sequence identity to each other. This gene models set was deeply characterized. (1) First, we have analyzed domain architecture and identified, in addition to typical domain combinations, the presence of particular domains like signal peptides, zinc fingers, kinases, heavy-metal-associated and WRKY DNA-binding domains. (2) Functional and expression annotation via homology searches in protein and transcript databases, based on sufficient criteria, enabled identifying similar proteins for 60 % of the studied gene models and expression evidence for 13 % of them. (3) Shared orthologous groups were defined using NBS-domain proteins of rice and Brachypodium distachyon. (4) Finally, alignment of the 436 NBS-containing gene models to the full set of scaffolds from the IWGSC's wheat chromosome survey sequence enabled high-stringence anchoring to chromosome arms. The distribution of the R genes was found balanced on the three wheat sub-genomes. In contrast, at chromosome scale, 50 % of members of this gene family were localized on 6 of the 21 wheat chromosomes and ~22 % of them were localized on homeologous group 7. The results of this study provide a detailed analysis of the largest family of plant disease resistance genes in allohexaploid wheat. Some structural traits reported had not been previously identified and the genome-derived data were confronted with those stored in databases outlining the functional specialization of members of this family. The large reservoir of NBS-type genes presented and discussed will, firstly, form an important framework for marker-assisted improvement of resistance in wheat, and, secondly, open up new perspectives for a better understanding of the evolution dynamics of this gene family in grass species and in polyploid systems.

Genetica, 2015

Mariner-like elements (MLEs) are Class II transposons present in all eukaryotic genomes in which ... more Mariner-like elements (MLEs) are Class II transposons present in all eukaryotic genomes in which MLEs have been searched for. This article reports the detection of MLEs in seven of the main fruit tree aphid species out of eight species studied. Deleted MLE sequences of 916-919 bp were characterized, using the terminal-inverted repeats (TIRs) of mariner elements belonging to the mauritiana Subfamily as primers. All the sequences detected were deleted copies of full-length elements that included the 3 0-and 5 0-TIRs but displayed internal deletions affecting Mos1 activity. Networks based on the mtDNA cytochrome oxidase subunit-I (CO-I) and MLE sequences were incongruent, suggesting that mutations in transposon sequences had accumulated before speciation of tree aphid species occurred, and that they have been maintained in this species via vertical transmissions. This is the first evidence of the widespread occurrence of MLEs in aphids.

Pest Management Science, 2012

BACKROUND: The melon fruit fly Bactrocera cucurbitae and the peach fruit fly Bactrocera zonata ar... more BACKROUND: The melon fruit fly Bactrocera cucurbitae and the peach fruit fly Bactrocera zonata are serious pests, native to Asia, that have recently invaded Egypt. In Tunisia, no report of these species has yet been made, but pest risk data suggest that both Bactrocera species are likely to establish in other countries of the Mediterranean region. RESULTS: A quick method, based on a PCR-RFLP of the mitochondrial COI gene, has been developed to enhance species identification for quarantine purposes. The restriction enzymes DdeI and XmnI were used to digest COI PCR products, enabling a rapid diagnosis of B. cucurbitae and B. zonata and their distinction from Tunisia's most devastating fruit pest, Ceratitis capitata. CONCLUSION: The simplicity and relatively low cost of this molecular approach will replace the need to rear immature stages through to adults for identification and will facilitate rapid quarantine decisions providing greater plant protection.

Molecular Genetics and Genomics, 2014

second step, sequences were used as initial seeds to walk up and downstream the nBS domain. This ... more second step, sequences were used as initial seeds to walk up and downstream the nBS domain. This procedure enabled identifying 8 loci ranging in size between 2,115 and 7,653 bp. Ab initio gene prediction identified 8 gene models, among which two had complete OrFs. While Gen-Bank survey confirmed the belonging of sequences to two groups, subsequent characterization using IWGSC genomic and proteomic data showed that the 8 gene models, reported in this study, were unique and their loci matched scaffolds on chromosome arms 1aS, 1BS, 4BS and 1DS. The gene model located on 1DS is a pseudo-Lr21 that was shown to have an nBS-lrr domain structure, while the potential association of the rGas, here reported, is discussed. This study has produced novel R-gene-like loci and models in the wheat genome and provides the first steps toward further elucidation of their role in wheat disease resistance.