Morphological and molecular characterization of Fusarium spp. associated with olive trees dieback in Tunisia

Abstract

Dieback and wilting symptoms caused by complex soilborne fungi are nowadays the most serious threatening disease affecting olive trees (Olea europaea) in Tunisia and presumably in many Mediterranean basin countries. Fusarium is one of the important phytopathogenic genera associated with dieback symptoms of olive trees. The objective of the present study was to confirm the pathogenicity of Fusarium spp. isolated from several olive-growing areas in Tunisia. According to the pathogenic test done on young olive trees (cv. Chemlali), 23 out of 104 isolates of Fusarium spp. were found to be pathogenic and the others were weakly or not pathogenic. The pathogenic Fusarium spp. isolates were characterized using molecular methods based on ITS PCR. Isolation results revealed the predominance of Fusarium solani (56.5%) and F. oxysporum species (21.7%) compared to F. chalmydosporum (8.7%), F. brachygibbosum (8.7%) and F. acuminatum (4.34%). Based on pathogenicity test, disease severity was highly variable among the 23 pathogenic isolates tested (P < 0.05) where F. solani was the most aggressive dieback agent. To the best of our knowledge, this is the first work that shows that Fusarium spp. might be a major agent causing dieback disease of olive trees in Tunisia.

Análisis filogenético multilocus del complejo fúngico asociado a pudrición radicular de sandía en Sonora, México

“…As a preliminary product of this investigation, F. brachygibbosum was reported for the first time as a pathogenic agent, causing this wilting in watermelon seeds (Rentería-Martínez et al, 2015). It has recently been recorded as a causal agent of rotting in the stem of maize plants (Shan et al, 2017), wilting and regressive death in Euphorbia larica and olive trees (Al-Mahmooli et al, 2013;Trabelsi et al, 2017) and of rotting and cankers in almond and chestnut trees (Stack et al, 2017;Marek et al, 2013).…”

“…Como producto preliminar de esta investigación, F. brachygibbosum fue reportado por primera vez como agente pató-geno, causante de marchitez en plantas de sandía (Rentería-Martínez et al, 2015). Recientemente se ha registrado como agente causal de podredumbre del tallo del maíz (Shan et al, 2017), marchitez y muerte regresiva en Euphorbia larica y olivo (AlMahmooli et al, 2013;Trabelsi et al, 2017) y de podredumbre y cancros en almendro y nogal (Stack et al, 2017;Marek et al, 2013).…”

In vitro and field responses of various active ingredients to Fusarium proliferatumspecies which causes Fusarium root rot disease in Indian mulberry (Morinda officinalis How.) in Thai Nguyen

“…Disease severity was recorded on 0 to 3 visual scales as previously described by Trabelsi, et al (2017) [2]. All infected plants in each treatment were recorded for disease incidence (%) using the following formula:…”

Root and crown rot pathogens causing wilt symptoms on field-grown marijuana (Cannabis sativa L.) plants

“…Simultaneous co-inoculations of multiple pathogens were not performed in this study but may have additive effects in promoting disease symptoms. On olive and watermelon plants, other species of Fusarium, including F. solani and F. oxysporum, were also associated with diseased tissues that contained F. brachygibbosum, as part of a disease complex (Renteria-Martinez; Trabelsi et al, 2017). On almond, both F. acuminatum and F. avenaceum were also found to be present in diseased tissues (Marek et al, 2013).…”