Identification de Pseudomonas syringae dans les cultures de tomate (Lycopersicum esculentum L.) de la région de Mostaganem et étude de la toxicité de quelques fongicides à l’égard du pathogène

الموضوعات

زراعة

الملخص

The compaign 2018-2019 has been particulary damaging to the late-saison tomato crop inthe mostaganem region. Indeed, considerable yield losses, reaching 100% in certain fields arerecorded.In the field or greenhouse, the symptoms are the same. Brown necrosis are visible in allaerial parts of the plant. On leaves, the necroses are surrounded by yellow halo.The origin of the disease is unknown. The symptomatic study suggests Pseudomonassyringae pv. tomato, responsible of dangerous disease that have an economic impact on thetomato crop.The colonies obtained presented morphologically an identical appearance, namelysmall roud and smooth colonies, a creamy appearance and cream color. Four representativeisolates of sampled sites are characterized by biochemical assays and hypersensitivity on tobacco(LOPAT : L, Levane ; O, oxydase ; P, Pectinase ; A, Arginie deshydrolase ; T, Tabac).The tobacco hypersensitivity test gives a positive reaction, which confirms thepathogenicity of the bacterium. In addition, seedling of 3 or 4 leaves of the Susana varietyinoculated with the bacterium (108 CFU/ml) show the same symptoms as those obseved in openfields. The colonies reisolated from the seedlings have the same characteristics as the initialcolonies. The postulate of kock is verified.Gram staining indicates that the bacteria is Gram negative, rod-shaped.The results of the chemical tests show that bacterium is levan positive, catalase negative,oxidase positive and has neither Arginine deshydrolase nor nitrate reductase. The Hugh &Leifson test reveals an oxidative metabolism. On the basis of all these results the bacterium tunsout to pseudomons syrigae. This work requires complementary analyses, such as confirmation of theidentity of the bacterium by molecular analyzes based on the PCR-amplified 16S RNAr geneusing universal primers and identification of the pathovar using specific primers.In addition, we have tested the phytotoxicity of certain fungicides, including copperoxychloride, which is known to be toxic to the bacterium, against pseudomonas syringae isolates.The results of this test show a significant difference between the isolates. Among thefungicides tested, phosethyl aluminium is the most toxic to the bacterium. Copper oxychloridecomes in second place.

روابط وملفات

التعريف والنوع

رقم الوثيقة

edab198c-1686-46e3-805d-596da293af2f

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

ماستر (LMD)

نوع الملف

pdf text

أسماء الملفات

2055767_1.pdf, 2055767_2.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Djamel Mahiout ","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"Rym Kheira Boumaiza","title_ar":"اعداد","title_en":"Preparation"}]

اللغة

French

المصدر والدورية

اسم المصدر

Identification de Pseudomonas syringae dans les cultures de tomate (Lycopersicum esculentum L.) de la région de Mostaganem et étude de la toxicité de quelques fongicides à l’égard du pathogène

المحتوى والصفحات

عدد الصفحات

0

إشراف وإعداد

الإشراف

Djamel Mahiout

الإعداد

Rym Kheira Boumaiza

الاقتباسات الببليوغرافية