LIBRO-CONGRESO-CITRUS

were observed. Thus, other possible mechanisms of action can be involved. In this study, changes in
enzymatic activity and gene expression level of chitinase, ß-1,3-glucanase, peroxidase, and phenylalanine
ammonia lyase (PAL) in wounded and unwounded ‘Valencia late’ sweet orange treated with Na2CO3 and
NaHCO3 (3% w/v), were investigated. Both salts increased ß-1,3-glucanase, peroxidase, and PAL activities in
orange tissues, whereas chitinase activity decreased. Transcriptomic analyses confirmed PAL up-regulation,
particularly at 12 h after treatment. Thus, although other pathways cannot be excluded, the defense
response induced by Na2CO3 and NaHCO3 in citrus fruit seems to be correlated with the up-regulation of
phenylpropanoid pathway, which has a role in the adaptation process to various stresses. This response
could sum up to citrus natural reaction to wounding and pathogen attack, enhancing its protective effect.
The results suggest that induced resistance should be considered as one of the possible mechanisms of
salts in controlling postharvest citrus decay.
S09P23
In vitro and in vivo antifungal activity of eight medicinal plants against Citrus Sour Rot agent
Geotrichum candidum
Talibi I., Askarne L., Boubaker H., Boudyach E.H., and Ait Ben Aoumar A.
Laboratoire des Biotechnologies et Valorisation des Ressources Naturelles (LBVRN), Biologie, Maroc. drissdesa@gmail.com
The aim of this work was to find an alternative to the chemical fungicides currently used in the control of
Geotrichum candidum, the cause of Citrus Sour Rot. Hexane, chloroform, ethyl acetate and methanol extracts
of eight medicinal plants were evaluated for their in vitro and in vivo antifungal activity against G. candidum.
Cistus villosus, Ceratonia siliqua and Halimium umbellatum methanol extracts proved to be the most effective
inhibitors, totally inhibiting arthrospore germination of G. candidum at concentrations of 2.5 mg/mL and
lower. The methanol extracts of H. umbellatum, C. villosus and C. siliqua exhibited strong antifungal activity
with minimum inhibitory concentrations values ranged between 0.156 and 1.25 mg/mL, and minimum
fungicidal concentrations values ranged between 2.5 and 5 mg/mL. Incidence of Sour Rot was lowered to 0,
3.33 and 11.66% when mandarin fruit were treated with C. villosus, C. siliqua and H. umbellatum methanol
extracts at 50 mg/mL, respectively, compared with 95% in the control. These findings suggest that C. villosus,
H. umbellatum and C. siliqua plants may be useful and effective agents for control of Citrus Sour Rot. Such
natural products therefore represent a sustainable alternative to the use of synthetic fungicides.
S09P24
In vitro and in vivo antifungal activity of several Moroccan medicinal plants against Penicillium
italicum, the causal agent of Citrus Blue Mold
Askarne L., Talibi I., Boubaker H., Boudyach E.H., Msanda F., Saadi B., Serghini M.A., and Ait Ben Aoumar A.
Laboratoire de Biotechnologies et Valorisation des Ressources Naturelles (LBVRN), Biology, Morocco. as.latifa@gmail.com
Penicillium italicum is the most important pathogen causing Blue Mold in stored citrus fruit. Current
control treatments of the disease involve application of fungicides, which may have adverse effects on the
environment and promotes the development of strains resistant to the active compound. To overcome these
problems, and the increasing concern of consumers towards the use of fungicides, alternative methods for
decay control are being investigated. The use of natural substances is a promising alternative that has been
explored to manage postharvest decay of fruits. The aim of this study is to evaluate the antifungal activity of
50 plant species, harvested in south of Morocco, against P. italicum infection. The in vitro antifungal activity
of plant powders was determined using the agar plates method. Results showed that among the 50 plants
tested, the powder of Anvillea radiata and Thymus leptobotrys at a concentration of 10% (w/v) completely
inhibited mycelial growth of P. italicum. The effect of plant aqueous extracts on spore germination and germ
tube elongation varied significantly among the different plants. Aquous extracts with high in vitro activity
were also tested in vivo on sweet orange fruit. Incidence of Blue Mold was significantly lowered to 5 and 25%
when fruits were treated with Halimium umbellatum and Inula viscosa aqueous extracts, compared with 98%
in control fruits.
XII INTERNATIONAL CITRUS CONGRESS 2012 - 147
S09