Mise en évidence d’une variation intra spécifique chez Botrytis cinerea et lutte biologique in vitro par l’extrait de compost

Objectifs : Le présent travail oeuvre pour la mise en évidence de la variation intra spécifique chez Botrytis cinerea et de l’effet d’un extrait d’un compost de déchets urbains solides sur deux stades du cycle de vie de ce pathogène. Methodologie et Résultats : Des feuilles de tomate ont été inoculées par 22 souches de B. cinerea pour sélectionner les plus virulentes. Celles-ci sont repiquées dans des boîtes contenant des milieux à base d’extrait de compost pour évaluer la croissance et la sporulation. Les souches de B. cinerea isolées à partir des plantes de tomate se sont révélé les plus virulentes. La croissance et la sporulation des 5 souches sélectionnées ont été inhibées par les milieux à base d’extraits jusqu’à 95,24% et 100% respectivement. Conclusion et application de la recherche : L’étude du pouvoir pathogène de B. cinerea a montré l’existence d’une variation intra spécifique et l’efficacité des extraits de compost stérilisés sur B. cinerea in vitro prouve que des composés chimiques sont mis en jeu et suggère la possibilité d’utilisation de ces extraits et du compost in vivo sur la pourriture grise de la tomate. Mots clés : B. cinerea, variation intra spécifique, extrait de compost, croissance, sporulation

Effet de diverses souches du Trichoderma sur la croissance d'une culture de tomate en serre et leur aptitude à coloniser les racines et le substrat

Les champignons du genre Trichoderma, connus depuis 1887 pour leurs propriétés antagonistes, ont été utilisés comme agents de lutte biologique contre un large spectre de phytopathogènes. Récemment, certaines études ont démontré l'aptitude des Trichoderma à stimuler la croissance de certaines plantes. Ainsi, l'effet de six souches du Trichoderma sur les paramètres de croissance et de rendement d'une culture de tomate en serre a été étudié. Les résultats montrent que toutes les souches du T. harzianum ont stimulé la croissance de la tomate, notamment les biomasses végétative et racinaire, alors que le T. viride n'a pas eu un effet significativement différent par rapport au témoin. L'effet du Trichoderma sur l'incidence des maladies foliaires a aussi été très net pour des souches de T. harzianum qui ont protégé à 100 % les feuilles de tomate. La colonisation des racines par les différentes souches du Trichoderma ne diffère pas significativement entre les souches du T. harzianum (86 à 100 %), alors qu'elle est significativement plus faible pour la souche TV1 du T. viride. De même, les souches du Trichoderma ont pu se maintenir à un niveau très élevé dans la rhizosphère par rapport aux témoins.Fungi in the genus Trichoderma, known since 1887 for their antagonistic properties, have been used as a biological control organism against several plant pathogens. Recently, studies showed the aptitude of Trichoderma to stimulate plant growth. Thus, the effect of six strains of Trichoderma on greenhouse tomato growth and yield was studied. The results show that all T. harzianum strains stimulated tomato growth, in particular the shoot and root weights, whereas T. viride did not have a significant effect. The effect of Trichoderma on leaf disease incidence was very clear since tomato leaves were completely protected (100%) by some T. harzianum strains. Root colonization by the various strains of Trichoderma did not differ significantly between the T. harzianum strains (86 to 100%), whereas it was significantly lower for the TV1 strain of T. viride. Also, Trichoderma strains maintained a high concentration level in the rhizosphere compared with the controls

Biological Control of Tomato Grey Mould with Compost Water Extracts, Trichoderma sp., and Gliocladium sp.

Compost water extracts prepared from animal sources (horse, sheep, and cattle) and a plant source (olive) were tested for their control of leaf grey mould on tomato. Disease was reduced by 27–66% and by 41–70% by extracts after 7 days and 15 days of fermentation respectively. No effect was noted with extracts after only 10 hours of fermentation. Conidial suspensions of Trichoderma harzianum, of Gliocladium sp. and compost extracts derived from horses achieved similar and significant (

Environmental Literacy of Indigenous Communities and Urban Communities On Lombok Island

Background: The high ability of community environmental literacy can form ideal environmental conditions, but indigenous peoples and urban communities have different understandings of environmental conditions. This study aimed to determine differences in the environmental literacy of indigenous peoples and urban communities on Lombok Island. Methods: The objects of this research are the indigenous people of Bayan Village, North Lombok, and the people of the Dasan Sari Environment, Mataram City, West Lombok: quantitative research methods, quantitative descriptive approaches, and survey research types. Data collection tools are observation, interviews, and questionnaires. Data analysis using SPSS, data analysis techniques by calculating the mean score of the questionnaire. Results: The study obtained a mean environmental literacy value for the indigenous people of Bayan Village at 214.37 and for the Dasan Sari Environmental community at 240.56. The results of the hypothesis testing in this study obtained a significance value greater than 0.05 and t-count < t-table. Conclusions: There was no real difference in environmental literacy between indigenous peoples and urban communities on Lombok Island

In vivo effect of some fungicides on the development of Pyricularia grisea and Helminthosporium oryzae

The effect of various fungicide treatments of seeds and leaves of rice on the development of the pathogenic fungi Pyricularia grisea and Helminthosporium oryzae was studied. When applied to seeds, tricyclazole, mancozeb and the carboxin+thiram combination were the only fungicides that reduced all the symptoms induced by both pathogens without damaging the development of young plants. Tricyclazole and the tricyclazole+mancozeb protected rice plants against P. grisea and H. oryzae respectively throughout the vegetative phase. To ensure protection during the entire vegetative phase, pyrazophos should be applied every two weeks while the carboxin+thiram combination, thiabendazole and mancozeb should be applied every week

Pathogenicity of Helminthosporium rostrata on rice varieties widely grown in Morocco

The plants of rice varieties (Arco, Thaibonnet and Elio) were inoculated with three isolates of Helminthosporium rostrata (HR1 HR2 and HR3), isolated for the first time in Morocco from the rice seed of Taibonnet variety at the end of the growing season. The results obtained showed that all the isolates are able to induce the disease on rice plants and sporulate on the foliar lesions. HR1, HR2 and HR3 was respectively the most pathogenic on Elio (I.C = 113), Arco (I.C = 212.5), and Taibonnet (130.48). The symptoms induced by the isolates are similar to those induced by Helminthosporium sativum on rice

Quantitative and qualitative estimation of Moroccan Trichoderma isolates capacity to solubilize rock phosphate

Thirty Trichoderma isolates isolated from compost, various crops and soil with roots of adjacent sites to the phosphate mines of Morocco, were tested in vitro for their potential to solubilize phosphorus from phosphate rock. The qualitative assessment of phosphate solubilization by Trichoderma isolates was performed on Modified Pikovskaya Agar (MPA) solid medium. The visual observation of the 3- and 6-day-old cultures did not show any clear zone around the colony. However, all the isolates were able to grow on the culture medium 3 days after incubation, the maximum recorded diameter was 58.6 mm for isolate TR-B 98 (3) and the minimum value was 34.8 mm for isolate TS-EM-98 (2). After 6 days, they showed good radial growth that exceeded 79.8 mm with variable appearance of the mycelial density such as the isolates TS-B 98, TS-EM-98 (1) and TR-CB 2000 (1) that presented, respectively, high, regular and low mycelial density. Also, the Trichoderma isolates produced variable number of conidia on MPA medium. Quantitative estimation on the Modified Pikovskaya Broth (MPB) liquid medium showed a variable potential of the Trichoderma isolates to solubilize phosphate when the amount of soluble phosphorus remained low in the liquid medium without the fungus (0.26 mgL−1). The maximum concentration of soluble phosphorus was 11.92 mgL−1 with percentage of soluble phosphorus equal to 95.39% recorded by the isolate TR-TB 2000 after 9 days of incubation, followed by the isolates TR-B 98 (3), TS-B 98 and TR-EM 2 respectively, 11.20, 10.47 and 9.61 mgL−1 and 89.6, 83.76 and 76.38%. In addition, treatments with Trichoderma isolates provided a lower final broth pH which varied between 6.81 for TOL isolate and 3.40 for TS-B-2000 (2) compared to initial pH (7.2). The isolates that proved potent for phosphate solubilization displayed the highest fresh and dry weights such as TR-TB 2000 (FW = 4.11 g and DW = 2.56 g), while the lowest fresh and dry weight were noted in the weakest isolates for phosphate solubilization such as T27 (FW = 1.025 g and DW = 0.58 g). The high solubilization potential of Trichoderma isolates can be exploited for the solubilization of fixed phosphorus present in the soil, thus improving soil fertility and plant growth

Related flavonoids cause cooperative inhibition of the sarcoplasmic reticulum Ca²⁺ ATPase by multimode mechanisms.

This is the peer reviewed version of the following article: Ogunbayo, O. A., & Michelangeli, F. (2014). Related flavonoids cause cooperative inhibition of the sarcoplasmic reticulum Ca2+ ATPase by multimode mechanisms. FEBS Journal, 281(3), 766-777, which has been published in final form at doi: 10.1111/febs.12621. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Flavonoids are group of plant-derived hydroxylated polycyclic molecules found in fruit and vegetables. They are known to bio-accumulate within humans and are considered to have beneficial health effects, including cancer chemoprotection. One mechanism proposed to explain this is that they are able to induce apoptosis in cancer cells by inhibiting a variety of kinases and also the Ca²⁺ ATPase. An investigation was undertaken with respect to the mechanism of inhibition for three flavonoids: quercetin, galangin and 3,6 dihydroxyflavone (3,6-DHF). Each inhibited the Ca²⁺ ATPase with K(i) values of 8.7, 10.3 and 5.4 μM, respectively, showing cooperative inhibition with n ~ 2. Given their similar structures, the flavonoids showed several differences in their mechanisms of inhibition. All three flavonoids stabilized the ATPase in the E₁ conformation and reduced [³²P]-ATP binding. However, both galangin and 3,6-DHF increased the affinity of Ca²⁺ for the ATPase by decreasing the Ca²⁺-dissociation rate constant, whereas quercetin had little effect. Ca²⁺-induced changes in tryptophan fluorescence levels were reduced in the presence of 3,6-DHF and galangin (but not with quercetin), indicating that Ca²⁺-associated changes within the transmembrane helices are altered. Both galangin and quercetin reduced the rates of ATP-dependent phosphorylation and dephosphorylation, whereas 3,6-DHF did not. Modelling studies suggest that flavonoids could potentially bind to two sites: one directly where nucleotides bind within ATP binding site and the other at a site close by. We hypothesize that interactions of these two neighbouring sites may account for both the cooperative inhibition and the multimode mechanisms of action seen with related flavonoids

Beer and its Non-Alcoholic Compounds: Role in Pancreatic Exocrine Secretion, Alcoholic Pancreatitis and Pancreatic Carcinoma

In this article we provide an overview of the newest data concerning the effect of non-alcoholic constituents of alcoholic beverages, especially of beer, on pancreatic secretion, and their possible role in alcoholic pancreatitis and pancreatic carcinoma. The data indicate that non-alcoholic constituents of beer stimulate pancreatic enzyme secretion in humans and rats, at least in part, by direct action on pancreatic acinar cells. Some non-alcoholic compounds of beer, such as quercetin, resveratrol, ellagic acid or catechins, have been shown to be protective against experimentally induced pancreatitis by inhibiting pancreatic secretion, stellate cell activation or by reducing oxidative stress. Quercetin, ellagic acid and resveratrol also show anti-carcinogenic potential in vitro and in vivo. However, beer contains many more non-alcoholic ingredients. Their relevance in beer-induced functional alterations of pancreatic cells leading to pancreatitis and pancreatic cancer in humans needs to be further evaluated