Browsing by Author "Sdiri, Yosra"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Biocontrol ability and production of volatile organic compounds as a potential mechanism of action of olive endophytes against Colletotrichum acutatumPublication . Sdiri, Yosra; Lopes, Teresa; Rodrigues, Nuno; Silva, Kevin; Rodrigues, Isabel; Pereira, J.A.; Baptista, PaulaOlive anthracnose, mainly caused by Colletotrichum acutatum, is considered a key biotic constraint of the olive crop worldwide. This work aimed to evaluate the ability of the endophytes Aureobasidium pullulans and Sarocladium summerbellii isolated from olive trees to reduce C. acutatum growth and anthracnose symptoms, and to assess A. pullulans-mediated changes in olive fruit volatile organic compounds (VOCs) and their consequences on anthracnose development. Among the endophytes tested, only A. pullulans significantly reduced the incidence (up to 10-fold) and severity (up to 35-fold) of anthracnose in detached fruits, as well as the growth (up to 1.3-fold), sporulation (up to 5.9-fold) and germination (up to 3.5-fold) of C. acutatum in dual culture assays. Gas chromatography–mass spectrometry analysis of olives inoculated with A. pullulans + C. acutatum and controls (olives inoculated with C. acutatum, A. pullulans or Tween) led to the identification of 37 VOCs, with alcohols being the most diversified and abundant class. The volatile profile of A. pullulans + C. acutatum revealed qualitative and quantitative differences from the controls and varied over the time course of microbial interactions. The most significant differences among treatments were observed at a maximal reduction in anthracnose development. At this stage, a set of VOCs, particularly Z-3-hexen-1-ol, benzyl alcohol and nonanal, were highly positively correlated with the A. pullulans + C. acutatum treatment, suggesting they play a critical role in anthracnose reduction. 6-Methyl-5-hepten-2-one and 2-nonanone were positively associated with the C. acutatum treatment and thus likely have a role in pathogen infection.
- Potential application of endophytes in the management of olive fruit fly and anthracnosePublication . Sdiri, Yosra; Baptista, Paula; Pereira, J.A.Olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), and olive anthracnose, mainly caused by Colletotrichum acutatum, are considered key biotic constrains of olive crop worldwide. Strategies employed for controlling this pest and disease are mostly based on the use of insecticides and copper-based pesticides, respectively, which is not compatible with sustainable production systems. This work aims to study the effect of two endophytes, previously isolated from olive tree, namely Aureobasidium pullulans and Sarocladium summerbellii on the behavior (i.e. attractiveness or repellence) and preference for oviposition of B. oleae, as well as on anthracnose infection, by using in vitro and in vivo (detached fruits) assays. Aureobasidium. pullulans-mediated changes in olive fruit volatile organic compounds (VOCs) and their consequences for anthracnose disease development were also evaluated. The tests performed by multi-choice olfactometer showed that both endophytes did not exert a repellent or attractive effect against mature gravid B. oleae female’s. Similarly, females did not showed preference to oviposit in olives inoculated with endophytes versus non-inoculated. Among the two endophytes tested, only A. pullulans inhibited significantly the growth (up to 1.3-fold), sporulation (up to 5.9-fold) and spore germination (up to 3.5-fold) of C. acutatum in relation to the control (C. acutatum). Similarly, in inoculated olive assays, only A. pullulans was able to reduced significantly progress curve for incidence (up to 10-fold) and severity (up to 35-fold) of anthracnose, as well as both sporulation (up to 90%) and germination (up to 70%) of C. acutatum, in comparison with olives inoculated solely with C. acutatum. Gas chromatography–mass spectrometry analysis of olives inoculated with A. pullulans+C. acutatum and controls (olives inoculated with C. acutatum, A. pullulans or tween) led to identification of 29 VOCs, belonging to 10 different chemical classes, being alcohols the most diversified and abundant ones. The volatile profile of A. pullulans + C. acutatum revealed quali- and quantitatively differences from the controls, in particular due to the production of (z)-3-hexen-1-ol and acetic acid, hexyl ester. These findings provide new viable possibilities of controlling olive anthracnose using the endophyte A. pullulans and/or their VOCs. These volatile inhibitory metabolites should be further tested against anthracnose.