Pathogenic and genetic characterization of Algerian isolates of Fusarium oxysporum f. sp. lentis by RAPD and AFLP analysis

Thirty-two isolates of Fusarium oxysporum f. sp. lentis were isolated from wilted lentil plants collected from different lentil growing areas in north-west Algeria. A pathogenicity test was performed for all isolates. Results indicated that the Fol isolates represent a single race but differ in their aggressiveness on the susceptible lines. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 6 RAPD primers and 3 AFLP selective nucleotide primer pairs. All amplifications revealed scorable polymorphisms among the isolates, and a total of 8 polymorphic fragments were scored for the RAPD primers and 93 for the AFLP primers. Genetic similarity between each of the isolates was calculated by using the Jaccard similarity coefficient and cluster analysis was used to generate a dendrogram showing relationship between them. The isolates could be grouped into two subpopulations based on RAPD and AFLP analysis. Results obtained indicate that there is little genetic variability among a subpopulation of Fol as identified by RAPD and AFLP markers and that there is no apparent correlation with geographical origin or aggressiveness of isolates. Also, the data suggest that Fol isolates are derived from two genetically distinct clonal lineages. Key Words: Lens culinaris, Fusarium wilt, molecular markers, pathogenicity. African Journal of Biotechnology Vol.3(1) 2004: 25-3

Distribution of races of Pyrenophora tritici-repentis in Algeria and identication of a new virulence type

Tan spot, caused by Pyrenophora tritici-repentis, is a foliar disease  of wheat, responsible for high economic losses in several wheat  growing areas in the world. There are eight known races of P. tritici-repentis based on ability to induce necrosis and/or chlorosis on a set of differential cultivars. Fifty five isolates of P. tritici-repentis  originating from diverse wheat growing regions in Algeria were  studied to determine which races are present and to identify new  races. Races 1, 4, 5, 6, 7 and 8 were found and a new virulence pattern was identified. Isolates with this pattern induced necrosis in durum  wheat but failed to induce any disease in the common wheat  genotypes in the differential set

Barley Leaf Stripe Disease in Algeria: Evaluation of Virulent Pyrenophora graminea Isolates and Identification of Resistant Algerian Barley Genotypes

Nine isolates of Pyrenophora graminea, barley leaf stripe disease causal agent, collected from several regions in Algeria were evaluated under greenhouse conditions for their virulence to a collection of barley cultivars including three most cultivated Algerian varieties. Virulence levels were observed among the set of isolates and a mean disease rate ranging from 3.33% to 75.83% was found. Pathogenic variability of P. graminea and resistant gene effects in barley cultivars were revealed. Isolate OS was the most virulent among P. graminea isolates making it a suitable virulent isolate in future breeding programs. A set of 8 barley genotypes composed of common Algerian cultivars and local developed lines were tested for their reaction to P. graminea and yield response. Barley cultivar Minnesota 23 and line 18/17/7L2 were the most resistant of the collection with high grain number/ear and thousand grains weight even when diseased. These genotypes could be useful to integrate as candidate genitor plants into barley breeding programs to develop resistant cultivars to leaf stripe disease

Distribution of large-spored Alternaria species associated with early blight of potato and tomato in Algeria

Potato and tomato are important crops in Algerian agriculture, and both are threatened by abiotic and biotic stresses, and early blight is a major disease affecting both crops. Surveys carried out from 2012 to 2015 in 12 major growing regions for these crops yielded a total of 247 Alternaria isolates having morphological and cultural characteristics of sections Alternaria and Porri. Since early blight symptoms and morphological characteristics of the isolates did not allow sharp distinction between the different large-spored species of Alternaria, the isolates in section Porri, often considered primary causes of the diseases, were selected for molecular characterization by diagnostic PCR using specific primers. This allowed species identification of 147 Alternaria isolates as A. solani, A. protenta, A. grandis or A. linariae. These species were present on potato and tomato crops at varying frequencies, depending on the hosts and on bioclimatic locations. Pathogenicity tests for the four species, on detached leaflets and whole seedlings, showed that all were pathogenic to potato and tomato, with varying virulence. These results suggest that parasitic specialization of these Alternaria species on solanaceous plants should be reconsidered

Solid-State Fermentation of Trichoderma spp.: A New Way to Valorize the Agricultural Digestate and Produce Value-Added Bioproducts

In this study, the agricultural digestate from anaerobic biogas production mixed with food wastes was used as a substrate to grow Trichoderma reesei RUT-C30 and Trichoderma atroviride Ta13 in solid-state fermentation (SSF) and produce high-value bioproducts, such as bioactive molecules to be used as ingredients for biostimulants. The Trichoderma spp. reached their maximum growth after 6 and 3 SSF days, respectively. Both Trichoderma species were able to produce cellulase, esterase, and citric and malic acids, while T. atroviride also produced gibberellins and oxylipins as shown by ultraperformance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) profiling. Experimental evaluation of germination parameters highlighted a significant promotion of tomato seed germination and root elongation induced by T. atroviride crude extracts from SSF. This study suggests an innovative sustainable use of the whole digestate mixed with agro-food waste as a valuable substrate in fungal biorefineries. Here, it has been applied to produce plant growth-promoting fungi and bioactive molecules for sustainable agriculture

Phaeoacremonium species associated with Eutypa dieback and esca of grapevines in Algeria

Algerian grapevines showing symptoms of Eutypa dieback and esca were examined for the presence of Phaeoacremonium species. Species were identified on the basis of morphological and cultural characteristics as well as DNA sequence data (β-tubulin and actin). From a total of 200 vines sampled, 61 Phaeoacremonium isolates were obtained corresponding to four different species. Pm. aleophilum was the most frequently isolated (n=42) followed by Pm. parasiticum (n=10) and Pm. venezuelense (n=8). Pm. hispanicum was also found but only once. Phaeoacremonium species were more frequently associated with Eutypa dieback than esca symptoms. This correlates with their frequent association with sectorial brown necrosis (V-shaped necrosis).Algerian grapevines showing symptoms of Eutypa dieback and esca were examined for the presence of Phaeoacremonium species. Species were identified on the basis of morphological and cultural characteristics as well as DNA sequence data (β-tubulin and actin). From a total of 200 vines sampled, 61 Phaeoacremonium isolates were obtained corresponding to four different species. Pm. aleophilum was the most frequently isolated (n=42) followed by Pm. parasiticum (n=10) and Pm. venezuelense (n=8). Pm. hispanicum was also found but only once. Phaeoacremonium species were more frequently associated with Eutypa dieback than esca symptoms. This correlates with their frequent association with sectorial brown necrosis (V-shaped necrosis)

Evaluating the Resistance of Tomato Cultivars to Algerian <i>Phytophthora infestans</i> Genotypes under Controlled Trial

Late blight is a destructive disease of solanaceous crops such as tomato (Solanum lycopersicum L.), caused by the Oomycete Phytophthora infestans (Mont.) de Bary. Late blight is generally controlled by fungicide applications, which quickly become ineffective due to the appearance of new P. infestans genotypes that can overcome the resistance of improved tomato cultivars and cause total production losses. The aim of this study is to assess the resistance level of tomato cultivars under controlled conditions and inoculations were carried out on detached leaflets (cvs. Trakia, Saint Pierre and Marmande) using inoculums of the major P. infestans clonal lineages found in Algeria such as EU_13_A2 (n = 1), EU_23_A1 (n = 2) and EU_2_A1 (n = 1) (three replicates of each isolate). This investigation showed that the choice of resistant cultivars can help control late blight and provide economic and environmental advantages by reducing the use of inputs

Full Length Research Paper - Pathogenic and genetic characterization of Algerian isolates of Fusarium oxysporum f. sp. lentis by RAPD and AFLP analysis

Thirty-two isolates of Fusarium oxysporum f. sp. lentis were isolated from wilted lentil plants collected from different lentil growing areas in north-west Algeria. A pathogenicity test was performed for all isolates. Results indicated that the Fol isolates represent a single race but differ in their aggressiveness on the susceptible lines. The amount of genetic variation was evaluated by polymerase chain reaction (PCR) amplification with a set of 6 RAPD primers and 3 AFLP selective nucleotide primer pairs. All amplifications revealed scorable polymorphisms among the isolates, and a total of 8 polymorphic fragments were scored for the RAPD primers and 93 for the AFLP primers. Genetic similarity between each of the isolates was calculated by using the Jaccard similarity coefficient and cluster analysis was used to generate a dendrogram showing relationship between them. The isolates could be grouped into two subpopulations based on RAPD and AFLP analysis. Results obtained indicate that there is little genetic variability among a subpopulation of Fol as identified by RAPD and AFLP markers and that there is no apparent correlation with geographical origin or aggressiveness of isolates. Also, the data suggest that Fol isolates are derived from two genetically distinct clonal lineages

In Vitro Morphological Characteristics of Pyrenophora tritici-repentis Isolates from Several Algerian Agro-Ecological Zones

Tan spot caused by the fungus Pyrenophora triticirepentis is a serious disease of wheat, which is on increase in recent years in Mediterranean region. In the field this fungus produces a diamond-shaped necrotic lesions with a yellow halo on wheat foliage. The objective of this study was to characterize and compare several monospore isolates of P. tritici-repentis collected from different infected wheat fields in various locations of Algeria, and find the morphological differences between them, if any. The results revealed wide morphologically variation among the isolates based on colony colors and texture, mycelial radial growth and conidial size

Preliminary characterization of potato virus Y (PVY) populations in Algerian potato fields

To date, only limited data are available concerning the viral pressure present in potato crops in Algeria. For three consecutive years, surveys were conducted in potato fields in the main Algerian potato-growing regions during the mid-season crop cycle (January to March). A total of 285 potato samples were characterized to define the prevalence of the five most common virus species: Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus X (PVX), Potato virus A (PVA) and Potato virus S (PVS). The results showed a higher incidence of PVY compared to the other four viruses. Because of this predominance of PVY and its distribution in all of the scouted regions, an analysis was carried out on the diversity of PVY populations. From a panel of 185 samples, serologically confirmed as being solely infected by PVY, 96.7% were found to be of serotype-N, and only 3.2% of serotype-O. A set of 31 PVY isolates was further analyzed by biotyping on tobacco and by molecular typing (RT-PCR, sequencing), targeting the nucleotide sequence polymorphism in the 5'NTR/P1 region and the three recombination junctions within the HC-Pro/P3 (RJ2), VPg/NIa (RJ3) and CP (RJ4) regions. All 28 PVY isolates from serotype-N inducing vein necrosis on tobacco were recombinant PVYNTN isolates. Among the three PVY isolates of serotype-O, two were typed as PVYN-Wi and induced vein necrosis on tobacco. This is the first report of the identification of NTN and Wilga type isolates in Algeri