Mohamed El Amine Kouadri

Potato (Solanum tuberosum L.) tuber dry rot caused by Fusarium spp. is a major postharvest disease responsible for significant storage losses worldwide. This study investigated Fusarium isolates recovered from symptomatic potato tubers collected in February 2025 from storage facilities in the Mascara region of Algeria. To our knowledge, this is the first regional characterization of Fusarium-associated dry rot in stored potato tubers from Mascara, Algeria. By integrating morphological characterization, quantitative pathogenicity assessment, and targeted molecular identification, the study examined the relationship between morphotype occurrence and disease-causing potential. A total of 118 purified Fusarium isolates were obtained from symptomatic potato tubers and grouped into 28 morphotypes based on cultural and morphological characteristics. One representative isolate from each morphotype was evaluated for pathogenicity on potato tubers of cv. ‘Arizona’ under controlled incubation conditions, and disease severity was quantified by image analysis. Of the 28 representative isolates tested, 15 induced dry rot symptoms, with marked differences in aggressiveness, whereas several isolates induced little or no necrosis under the conditions tested. Selected aggressive isolates were further analyzed using TEF1-α sequencing, which identified F14 as F. sambucinum and F171 as F. redolens, while F4 and F34 were identified to the F. oxysporum and F. solani species-complex level, respectively. Importantly, morphotype frequency did not necessarily reflect disease severity, as some of the most aggressive isolates belonged to less common morphotypes. These findings suggest that isolation frequency alone may not adequately reflect pathogenic importance and support the integration of occurrence data, pathogenicity testing, and molecular identification in the assessment of Fusarium-associated dry rot in potato storage systems.

Gray mold, caused by the necrotrophic fungus Botrytis cinerea, was responsible for significant economic losses in grapevine (Vitis vinifera L.) production worldwide, including Algeria, which highlighted the need for sustainable control alternatives. The objective of this study was to evaluate the antagonistic potential of an indigenous Trichoderma harzianum strain against local B. cinerea isolates from Mascara, Algeria. A highly virulent B. cinerea isolate (BC3) was collected from infected grapevine leaves and identified through morphological and molecular analyses, while the antagonistic T. harzianum isolate (T5) was obtained from the rhizosphere of healthy vines. In vitro dual-culture assays showed that T. harzianum significantly inhibited the mycelial growth of B. cinerea, with direct inhibition of 80.50 % and indirect inhibition of 72.87 %. In vivo experiments further confirmed its efficacy, reducing disease incidence by 56.25 % and enhancing plant growth, increasing height from 60 to 96 cm with notable improvement in vegetative biomass. These findings suggested that the indigenous T. harzianum T5 strain was a promising and effective biocontrol agent for the sustainable management of gray mold in vineyard.

During a survey conducted in June 2019, chlorosis symptoms were observed on lentil leaves in a field located at Relizane, Algeria. Based on morphological and molecular identification, the pathogen was identified as Alternaria chlamydosporigena. A pathogenicity test was carried out and Koch's postulates were verified and fulfilled. To our best knowledge, this is the first report of A. chlamydosporigena as new pathogen on lentil worldwide.

Background: Lentil (Lens culinaris Medik.) is one of the major pulse crops in the world. The present study aimed to evaluate the effect of Trichoderma isolates to control the charcoal rot disease caused by Macrophomina pseudophaseolina recently reported on lentil plants. Results: In this study, antagonistic effects of seven isolates of Trichoderma spp. isolated from the rhizosphere of lentil were evaluated in vitro against Macrophomina pseudophaseolina M1. All isolates of Trichoderma significantly reduced the mycelial growth of M1 in vitro. Maximum reduction of the pathogen growth was observed at T10 (72.53%), followed by T5 (63.7%) and T6 (62.88%), while T2 caused the minimum reduction (37.33%). Likewise, Trichoderma isolates significantly reduced the size and number microsclerotia. M1 produced the minimum number of microsclerotia in the presence of T10, followed by T1 causing reduction of 68.56 and 53.37% over control, respectively. The maximum reduction of microsclerotia’s size was observed in the presence of T10 (54.92%), followed by T1 (49.84) and T8 (48.68%). Results also revealed that production of volatile metabolite, components and inhibition of the test pathogen by volatile metabolites varied among different antagonistic Trichoderma. T1 produced the most volatile compounds, followed by T2 and T3 and T10 causing mycelial growth inhibition of 41.66, 33.88, 30.55 and 30.37%, respectively. The efficacy of the antagonistic biocontrol agents on charcoal rot was evaluated in vivo. Seed treatment with T10 significantly protected lentil seedlings from M. pseudophaseolina as compared to untreated plants and also improved their growth. T10 isolate was identified based on molecular tools, using internal transcribed spaces and Translation elongation factor of ribosomal DNA. The results identified T10 as Trichoderma longibrachiatum with accession number MW818102 and OK500004 deposited in NCBI GenBank database. Conclusion: The study revealed the first report of using Trichoderma longibrachiatum as a promising biological agent against M. pseudophaseolina causing charcoal rot disease of lentil.