Effect of soil management on biodiversity of nematode communities as a biological indicator of soil quality in oasis agro-ecosystem of Kebili

Nematode communities were monitored in 26 oases in Kebili under various agricultural systems. Differences between studied oases consisted in tillage frequency, soil amendment type (manure or manure+ mineral fertilizers), cover crops and field age. In addition, this study evaluated the importance of the C-P (Colonizer-Persistent) triangle and the faunal profile (representation of enrichment index vs. structure index) as a biological indicator and monitoring tools in support of soil quality assessment. The results showed that nematode communities were composed by 10 bacterial feeders (Ba), 3 fungal feeders (Fu), 12 plant parasites (PP), 4 omnivores (O), 1 predator (P) with the dominance of (Ba) and (PP) in all surveyed oases. The nematode communities differed slightly depending on oases age. Bacterial feeders and Discolaimium genus were found in both young and old ones. Plectus genus (Ba) was found only in young oases while Xiphinema, Criconema and Trichodorus genera (PP) were absent in these oases. Few nematode taxa were affected by soil amendment type and cover cropsincluding some bacterial and fungal feeders. The highest taxa richness was recorded in bare soils and in field with tillage frequency of 2 or 3 years. The lower MI (Maturity index) value was recorded in old oases. Most of studied oases were characterized either by a high soil disturbance level with a high abundance of cp-1 group (Bacterivore nematodes with c-p value =1)as an indicator of a disturbed food web or by a stressed soil with high abundance of cp-2 group (Bacterivore and fungivore nematodes with c-p value = 2) as an indicator of degraded food web. Only few sites showed a maturing and structured food webs with respectively low to moderate soil disturbance level and undisturbed soil. This study highlighted also that some nematode genera may potentially serve as differential bio-indicators of soil disturbance

Effects of Latex from Pergularia tomentosa and the Aggregation Pheromone, Phenylacetonitrile, on Locusta migratoria Larvae

Despite being a serious risk to human health and environment, chemical insecticides remain the most used for locust control. Searching for alternative control methods, effective and compatible with the environment, has become of increasing interest. Plant latex is an endogenous fluid secreted from highly specialized laticifer cells and has been suggested to act as a plant defense system. The aim of the present investigation was to study the insecticidal potentialities of Pergularia tomentosa latex at different concentrations, alone or in combination with the penylacetonitrile (PAN), on the 4th instar larvae of Locusta migratoria. The obtained results showed that the latex revealed an interesting insecticidal activity against L. migratoria larvae, resulting in a mortality reaching 96.49 %, 6 days after treatment. Toxicity bioassays revealed that PAN, associated with the latex, is able to accelerate and to increase the mortality rate. Pheromone-based treatment affected the health of treated insects by significantly reducing their respiratory rhythms. PAN was shown able to alter, quantitatively and qualitatively, the larval blood cells as expressed by the significant decrease in the number of the differential haemocyte counts (prohemocyte, plasmatocytes and granulocytes) and the important cell lysis

Biocontrol Effectiveness of Indigenous Trichoderma Species against Meloidogyne javanica and Fusarium oxysporum f. sp. radicis lycopersici on Tomato

In this study, three local isolates of Trichoderma (Tr1: T. viride, Tr2: T. harzianum and Tr3: T. asperellum) were isolated and evaluated for their biocontrol effectiveness under in vitro conditions and in greenhouse. In vitro bioassay revealed a biopotential control against Fusarium oxysporum f. sp. radicis lycopersici and Meloidogyne javanica (RKN) separately. All species of Trichoderma exhibited biocontrol performance and (Tr1) Trichoderma viride was the most efficient. In fact, growth rate inhibition of Fusarium oxysporum f. sp. radicis lycopersici (FORL) was reached 75.5% with Tr1. Parasitism rate of root-knot nematode was 60% for juveniles and 75% for eggs with the same one. Pots experiment results showed that Tr1 and Tr2, compared to chemical treatment, enhanced the plant growth and exhibited better antagonism against root-knot nematode and root-rot fungi separated or combined. All Trichoderma isolates revealed a bioprotection potential against Fusarium oxysporum f. sp. radicis lycopersici. When pathogen fungi inoculated alone, Fusarium wilt index and browning vascular rate were reduced significantly with Tr1 (0.91, 2.38%) and Tr2 (1.5, 5.5%), respectively. In the case of combined infection with Fusarium and nematode, the same isolate of Trichoderma Tr1 and Tr2 decreased Fusarium wilt index at 1.1 and 0.83 and reduced the browning vascular rate at 6.5% and 6%, respectively. Similarly, the isolate Tr1 and Tr2 caused maximum inhibition of nematode multiplication. Multiplication rate was declined at 4% with both isolates either tomato infected by nematode separately or concomitantly with Fusarium. The chemical treatment was moderate in activity against Meloidogyne javanica and Fusarium oxysporum f. sp. radicis lycopersici alone and combined

First Report of the Spiral Nematode Rotylenchus incultus (Nematoda: Hoplolaimidae) from Cultivated Olive in Tunisia, with Additional Molecular Data on Rotylenchus eximius

Spiral nematode species of the genus Rotylenchus have been reported on olive (Olea europaea L.) in several Mediterranean countries (Castillo et al., 2010; Ali et al., 2014). Nematological surveys for plant-parasitic nematodes on olive trees were carried out in Tunisia between 2013 and 2014, and two nematode species of Rotylenchus were collected from the rhizosphere of olive cv. Chemlali in several localities of Tunisia (Tables 1,​,2Table2). Twenty-two soil samples of 3 to 4 kg were collected with a shovel from the upper 50 cm of soil from arbitrarily chosen olive trees. Nematodes were extracted from 500 cm3 of soil by centrifugal flotation method (Coolen, 1979). Specimens were heat killed by adding hot 4% formaldehyde solution and processed to pure glycerin using the De Grisse’s (1969) method. Measurements were done using a drawing tube attached to a Zeiss III compound microscope. Nematode DNA was extracted from single individuals and PCR assays were conducted as described by Castillo et al. (2003). Moderate-to-low soil populations of these spiral nematodes were detected (5.5–11.5, 1.5–5.0 individuals/500 cm3 of soil, respectively).This prompted us to undertake a detailed morphological and molecular comparative study with previous reported data. Morphological and molecular analyses of females identified these species as Rotylenchus eximius Siddiqi, 1964, and Rotylenchus incultus Sher, 1965. The morphology of R. eximius females (five specimens studied) was characterized by having a hemispherical lip region clearly off set, with four to five annuli, body without longitudinal striations, lateral fields areolated in the pharyngeal region only, stylet 32 to 36 μm long, and broadly rounded tail. The morphology of R. incultus females (51 females and 16 males; Table 2) was characterized by a hemispherical lip region with the basal annulus subdivided by irregular longitudinal striations, with three, rarely four annuli; stylet 21.5 to 27.5 μm long, female tail hemispherical with terminus regularly annulated; phasmids anterior to anus level (3–6 annuli above). The morphology of the isolated nematodes agreed with previous descriptions of R. eximius (Siddiqi, 1964; Castillo and Vovlas, 2005) and R. incultus (Sher, 1965; Castillo and Vovlas, 2005; Vovlas et al., 2008), respectively. A single individual was used for DNA extraction. Primers and PCR conditions used in this research were specified in Cantalapiedra-Navarrete et al. (2013), and a single amplicon of 800, 1,100, and 450 bp was obtained and sequenced for D2 to D3, ITS1, and cytochrome c oxidase subunit 1 (coxI), respectively. Sequence alignments for D2 to D3 (KX669231-KX669233), ITS1 (KX669238-KX669240), and coxI (KX669244-KX669245) from R. eximius, showed 99% to 97%, 98% to 94%, 93% similarity to other sequences of R. eximius deposited in GenBank (EU280794-DQ328741, EU373663-EU373664, JX015401-JX015402, respectively). Similarly, D2 to D3 (KX669234-KX669237), ITS1 (KX669241-KX669243), and coxI (KX669246-KX669249) sequence alignments from R. incultus, showed 99%, 99% to 95%, 99% to 90% similarity, respectively, to other sequences of R. incultus deposited in GenBank (EU280797, EU373672-EU373673, JX015403, respectively). The best fitted model of DNA evolution was obtained using jModelTest v. 2.1.7 (Darriba et al. 2012) with the Akaike information criterion. BI analyses were performed under the general time reversible (GTR) with invariable sites and a gamma-shaped distribution of substitution rates (GTR + I + G) model for ITS1 and coxI. Phylogenetic analyses of ITS1 and coxI using Bayesian inference (BI) placed R. eximius and R. incultus from Tunisia in subclades that included all R. eximius and R. incultus sequences deposited in GenBank (Fig. 1), which agrees with previous results (Cantalapiedra-Navarrete et al., 2013). Morphology, morphometry, and molecular and phylogenetic data obtained from these samples were consistent with R. eximius and R. incultus identification. To our knowledge, this is the first report of R. incultus in Tunisia. Consequently, all these data suggest that spiral nematode species of the genus Rotylenchus are predominant in olive as previously reported in other Mediterranean areas (Ali et al., 2014).Peer reviewe

Integrative identification and molecular phylogeny of dagger and needle nematodes associated with cultivated olive in Tunisia

The occurrence and geographic distribution of longidorid nematode species inhabiting the rhizosphere of cultivated olive (cvs. Chemlali and Chétoui) in Tunisia were investigated. Morphological and morphometrical studies identified three Longidorus and six Xiphinema species, with frequencies of prevalence as following: Longidorus africanus (23.0 %), L. euonymus (4.5 %), L. glycines (13.7 %), Xiphinema conurum (13.7 %), X. italiae (36.4 %), X. meridianum (13.7 %), X. pachtaicum (18.2 %), X. robbinsi (9.1 %), and Xiphinema sp. (4.5 %). The three Longidorus species were reported for the first time in Tunisia, in addition to two species of Xiphinema (viz. X. meridianum and X. robbinsi). Molecular characterisation using D2-D3 expansion regions of 28S rRNA and ITS1-rRNA was carried out and Bayesian inference analysis was used to reconstruct phylogenetic relationships among these species and with other longidorids. Twenty-five new D2-D3 of 28S rRNA gene sequences were obtained in the present study, seven for Longidorus and 18 for Xiphinema spp., as well as 14 new ITS1 rRNA gene sequences (seven for Longidorus and seven for Xiphinema spp.).This research was supported by grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE "Contribution of olive history for the management of soilborne parasites in the Mediterranean basin" from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), grant AGR-136 from "Consejería de Economía, Innvovación y Ciencia" from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, "Una manera de hacer Europa". The fourth author is a recipient of a "Juan de La Cierva" contract from Ministerio de Economía y Competitividad of Spain.Peer reviewe

Acquired hemophilia A following COVID-19 vaccine: a case report

Abstract Background In the literature, reported cases of Acquired hemophilia A (AHA) induced by COVID-19 vaccination occurred after Adenoviral Vector Deoxyribonucleic Acid (DNA)- and SARS-CoV-2 Messenger Ribonucleic acid (mRNA)-Based vaccines. Here, and to the best of our knowledge, we report the first case of AHA occurring after an inactivated Sinovac-coronavac COVID-19 vaccine. Case presentation A 69-year-old Tunisian male patient consulted for severe left leg pain limiting physical mobility due to a 5*6 cm large ecchymosis located at the left inner thigh, having spontaneously appeared 5 days prior consultation and without notion of trauma. The patient had no known personal medical history. He had received the second dose of CoronaVac-SinoVac vaccine 30 days prior to consultation. Further physical examination revealed the presence of two other ecchymoses: one at the inner face of the right forearm, starting at the wrist reaching the elbow and the other at the left flank of the abdomen. Diagnosis of AHA was based on clinical presentation and confirmed with prolonged a PTT, Factor VIII deficiency and the presence of an FVIII inhibitor. The patient was successfully treated with corticosteroids and low dose Rituximab. Conclusion Clinicians should consider AHA in front of prolonged aPTT with or without spontaneous bleedings even after inactivated virus COVID-19

First Report of the Cyst Nematode Heterodera mediterranea on Olive Trees in Tunisia

A survey was conducted in Tunisia to detect the presence of plant parasitic nematodes associated to olive trees. A high infection of olive roots and soil by the cyst nematode Heterodera mediterranea was detected in olive orchards located in the region of Moknine (Monastir, Sahel of Tunisia). Integrative taxonomic approaches (morphological, morphometrical and molecular analyses) were carried out in order to characterize the Tunisian population of H. mediterranea. Phylogenetic analyses of the ITS region, the D2-D3 expansion segments of the 28S rRNA gene and 18S rRNA gene highly supported that H. mediterranea from Tunisia belongs to the Schachtii group. So far, this is the first report of this nematode in Tunisia