Phenotypic and genetic characterization of date palm cultivars resistant to bayoud disease

Taqerbucht cultivars of date palm are well known by their natural resistance against devastating fungus Bayoud disease. In order to know, if these accessions have the same genetic and morphological profile or each of them constitutes a separate cultivar, we carried out a morphological and molecular characterization and we compared four Taqerbucht (Tq.) date palm cultivars from the southwestern region of Algeria: Tq.hamra cultivar (red fruits), Tq. safra cultivar (yellow fruits), Tq.beïda (white fruits) and Tq.kahla cultivar (black fruits). Seventy one phenotypic characteristics, including 33 quantitative and 38 qualitative traits, have been selected for comparison. Principal component analysis (PCA) and multi-component clustering were used to analyze and compare the data. The results suggest that the four cultivars can be classified into distinct groups. One group contains one cultivar, the Tq.kahla and another group contains the three other cultivars (Tq.safra, Tq.beïda and Tq. hamra). Based on phylogenetic analyses and sequence comparisons, the cultivar Tq. kahla seems to be divergent from the cultivar Tq.hamra, whereas the two cultivars Tq.Safra and Tq.beïda are close to each other. Using 16 Simple Sequence Repeat (SSR) genetic markers to analyze genetic diversity among the cultivars, we found that 13 markers were detectable in 31 allele's loci, and the number of alleles per locus varied from 1–4 with an average of 2.38 alleles per locus. Expected heterozygosity (He) values ranged from 0.375–0.500 and observed heterozygosity (Ho) values from 0.750–1.000.

Biocontrol of Bayoud Disease (Fusarium oxysporum F. Sp. Albedinis) on Deglet-nour Variety of Date Palm (Phoenix dactylifera L.) in South Western Oases of Algeria

Background: This work has the objective to biocontrol the bayoud disease of date palm caused by the fungus Fusarium oxysporum f. sp. albedinis (Foa), is the major disease in Algerian palm groves of south western region. This in vivo biocontrol was done on date palm variety Deglet-Nour, using two antagonistic fungi species, Trichoderma harzianum and Aspergillus flavus.Methods: Twenty Foa isolates obtained from isolation of the spines carrying the typical symptoms of Bayoud disease were used. Two strains T. harzianum and A. flavus, were isolated from rhizosphere soils of the date palm trees. Using the greenhouse screening test, which was carried out on 3-4 month-old date palm seedlings at the rate of 5 ml of inoculum suspension.Result: A statistical analysis showed a significant (P less than 0.05), difference of Deglet-Nour seedlings reactions against Foa isolates and antagonistic fungi were observed. All date palm trees present susceptibility against Foa until the total mortality of seedlings. The biocontrol test showed that two antagonists showed different reaction, with the complete resistance for seedlings treated by T. harzianum with the mortality rate (rm%) reduced at 100%, while, the second antagonist A. flavus reduced the rm% at 25%. We can apply of these antagonistic fungi to protect our groves contaminated by Bayoud disease and also contain this susceptible commercial variety.

Mono-Alkylated Ligands Based on Pyrazole and Triazole Derivatives Tested Against Fusarium oxysporum f. sp. albedinis: Synthesis, Characterization, DFT, and Phytase Binding Site Identification Using Blind Docking/Virtual Screening for Potent Fophy Inhibitors

Twelve recent compounds, incorporating several heterocyclic moieties such as pyrazole, thiazole, triazole, and benzotriazole, made in excellent yield up to 37–99.6%. They were tested against Fusarium oxysporum f. sp. albedinis fungi (Bayoud disease), where the best results are for compounds 2, 4, and 5 with IC50 = 18.8–54.4 μg/mL. Density functional theory (DFT) study presented their molecular reactivity, while the docking simulations to describe the synergies between the trained compounds of dataset containing all the tested compounds (57 molecules) and F. oxysporum phytase domain (Fophy) enzyme as biological target. By comparing the results of the docking studies for the Fophy protein, it is found that compound 5 has the best affinity followed by compounds 2 and 4, so there is good agreement with the experimental results where their IC50 values are in the following order: 74.28 (5) < 150 (2) < 214.10 (4), using Blind docking/virtual screening of the homology modeled protein and two different tools as Autodock Vina and Dockthor web tool that gave us predicted sites for further antifungal drug design.

Exploring the potential of using bioactive plant products in the management of Fusarium oxysporum f.sp. albedinis: the causal agent of Bayoud disease on date palm (Phoenix dactylifera L.)

Background “Bayoud” disease caused by Fusarium oxysporum f. sp. albedinis (Foa) poses a serious threat to date palm (Phoenix dactylifera L.) in Morocco. However, research studies performed to discover biological methods to control this disease remain limited. The present study has set objectives to determine antifungal activity of five plants extracts (Acacia cyanophylla, Cupressus atlantica, Eucalyptus torquata, Nerium oleander, and Schinus molle) against Foa and link this effect to their content in polyphenols and flavonoids as well as their antioxidant properties. Results Plant extracts showed significant differences (p < 0.05) regarding their antifungal activity. The extracts of E. torquata and C. atlantica showed the strongest antifungal effect resulting in the inhibition of mycelial growth, sporulation, and spore germination in a dose-dependent manner. In addition, there were significant differences among the examined plant extracts in respect to their total polyphenols (1.536–7.348 g GAE/100 g DW), flavonoids (0.986–5.759 g RE/100 g DW), and antioxidant properties measured by Trolox equivalent antioxidant capacity (TEAC) (7.47–38.97 mmol TE/100 g DW) and ferric-reducing antioxidant power (FRAP) assay (8.95–47.36 mmol TE/100 g DW). Moreover, the antifungal potential of plant extracts was found to be moderately to strongly correlated with their polyphenol and flavonoid contents as well as their antioxidant activity, implying that the effective inhibitory activity of these plant extracts is partly due to their richness in antioxidative secondary metabolites. Conclusion Our findings shed further light on plants as a-yet-untapped resource of bioactive compounds and constructed the foundation for the development of new biological approaches to best manage Bayoud disease.

Draft Genome Sequence of Fusarium oxysporum f. sp. albedinis Strain Foa 133, the Causal Agent of Bayoud Disease on Date Palm

ABSTRACT Fusarium oxysporum f. sp. albedinis is the causal agent of vascular wilt of date palm. Here, we report the genome assembly of the Foa 133 strain, which consists of 3,325 contigs with a total length of 56,228,901 bp, a GC content of 47.42%, an N50 value of 131,587 bp, and 3,684 predicted genes.

Bioguided Fractionation of Citrullus colocynthis Extracts and Antifungal Activity Against Fusarium oxysporum f.sp. albedinis

Background: In the present study, a bioguided fractionation was realized to isolate bioactive compounds on Fusarium oxysporum f.sp. albedinis (Foa) from Citrullus colocynthis L. Foa is the causal agent of “ Bayoud”, a lethal disease of date palm. Methods: Extracts of Citrullus colocynthis fruits peels using four solvents (n-hexane, dichloromethane, ethanol, chloroform) were tested for antifungal effect on Foa with radial growth technique. The ethanolic extract was selected for fractionation to isolate bioactive compounds (Percentage of Growth Reduction “PGR”: 63.6%). The fractionation was realized using six solvents (hexane, dichloromethane, ethyl acetate, methanol, butanol, water). Through fractionation, methanolic and butanolic fractions (PGR= 57.6% and 69.7%, respectively) had been chosen for bioactive compounds isolation. Results: Chromatographic and spectroscopic analyses had led to isolation of six compounds deduced as: (C1): 2-O-β-D-glucopyranosylcucurbitacin E; (C2): 2-(Nonan-8-one)-(1H)-4-quinolone; (C3): 2- (Nonan-8-one) 4-methoxy-quinoline, (C4): Isosaponarin; (C5): Isovitexin; (C6): Isoorientin 3’-Omethyl ether. The isolated compounds had been tested for antifungal effect. The compound (C1) represents the best effect among isolated compounds (PGR, up to 54.5%). Conclusion: The efficiency of (C1) reflects its opportunity to be used for the development of efficient treatment against Bayoud disease.