Biological Control of Potato Bacterial Wilt Diseases

Potato (Solanum tuberosum L.) is considered one of the four major and important food crops around the world. This study planned to control bacterial wilt disease of potato using some bio-agents which isolated and identified from potato plant soil. Twenty isolates were selected and identified as the following three isolates belonging to Streptomyces spp. (Streptomyces antibioticus (SA1), S. albus (SA2), and S. mutabilis (SM1); five isolates belong to pseudomonas species (Pseudomonas fluoresces (PsF1), P. aeruginosa (PsA1), P. putida (PsP1), P. alecaligones (PsA2) and P. pseudoalcaligones (PsP2)) and twelve isolates were belonging to Bacillus spp. (Bacillus subtilis (BS1-8), B. cereus(BC1), B. badius (BB1-2), B. pumilus (BP1). In vitro, these isolates were examined against the growth R. solanacearum bacterium, where some isolates (BS3, PsF1, BS8, BS6, SM1, BS5, and BS4) were the most effective compared with other isolates. Bacillus subtilis (BS8); Pseudomonas fluorescence (PsF1) and Streptomyces mutabilis (SM1) isolates were selected as bio-agents to control potato bacterial wilt disease under in vivo condition, where these isolates led to reduced disease severity and to increase potato yield compared with the control. The application of bio-agents as drench treatment was more effective than tuber treatment, and isolates of S. mutabilis (SM1) and B. subtilis (BS8) were more effective than Pseudomonas fluorescence (PsF1) isolate

Management of Lettuce Bacterial Soft Rot Disease Using Biotic and Abiotic Agents under Field Conditions

The current investigation was planned to apply some biotic and abiotic treatments singlely and/or combined to control bacterial soft rot diseases of lettuce under field conditions in Qaha region, Qalyubia Governorate, Egypt. The application of resistance inducers (jasmonic acid and salicylic acid), antibiotics (norfloxacin and tetracycline) and bio-agents (isolates of B. subtilis and Ps. fluorescens) significantly reduced the disease severity as a single treatment compared to the control treatment. Obtained results indicated that resistance inducers appeared to be most effective against bacterial soft rot disease of lettuce compared with other treatments, while antibiotics were less effective at controlling the disease. However, the interaction between bio-agents as soil drench treatment, antibiotics, or resistance inducers as foliar treatment significantly reduced the severity of lettuce bacterial soft rot disease compared with the control treatment. Furthermore, the interaction between disease severity was more reducted with interaction treatments between Ps. fluorescens isolate rather than interact with treatments between B. subtilis isolate and other treatments. However, the interaction between the isolate of Ps. fluorescens as bio-agent treatment or norfloxacin as antibiotic or salicylic acid as a plant resistance inducer, were the most effective methods to control the disease compared with other treatments. Meanwhile, the interaction between resistance inducers and antibiotics as foliar treatments were significantly reduced from the severity of lettuce bacterial soft rot disease compared with the control treatment. Disease severity was more reduced with the application of interaction between norfloxacin and resistance inducers than the interaction between tetracycline and resistance inducers. Meanwhile, the severity of the disease decreased more with the application of interaction between salicylic acid and antibiotics than the interaction between jasmonic acid and antibiotics. Generally, all combination treatments were more efficient than single treatments alone to significantly manage the spread and the infection of the disease compared to the untreated control

ENDOPHYTIC BACTERIA ASSOCIATED WITH SUGARCANE AND ITS POTENTIAL TO SUPPRESS SPORISORIUM SCITAMINEUM, THE CAUSAL FUNGAL PATHOGEN OF SMUT DISEASE

Bacterial endophytic ubiquitously colonize the internal tissues of the plant. The purpose of this study was to isolate and identify the endophytic bacteria from sugarcane stalks which have antagonistic activity against Sporisorium scitamineum, the causal pathogen of sugarcane smut disease, and to study their activity to produce some secondary metabolites i.e. enzymes and growth-promoters.  Sugarcane samples were collected from five governorates in Upper-Egypt namely, Giza, Beni-Suef, Sohag, Qena, and Luxor. A total of 240 isolates of endophytic bacteria were isolated from 160 samples of healthy sugarcane stalks (variety GT-54-9). Isolated endophytes were screened for its antagonistic activity against S. scitamineum, in vitro, using dual culture method. Only, 62 isolates showed different degrees of antagonistic activity. Ten isolates of endophytic bacteria were selected to study their potential to produce enzymes (chitinase, β 1,3 glucanase, phenylalanine ammonia lyase) and growth-promoters (siderophores, indole acetic acid (IAA), salicylic acid (SA)). These isolates were pre-identified using the morphological and physiological properties according to Bergy's manual as Pseudomonas sp., Serratia sp., Enterobacteria sp., Herbaspirillium sp., Gluconacetobacter sp. Anabaenopsis sp. and Azospirillumsp. All endophetic bacteria produced β 1,3gluconase and indole acetic acid (IAA), while Pseudomonas sp. produced salicylic acid and phenylalanine ammonia lyase, Ana baenopsis sp. produced phenylalanine ammonia lyase, Gluconacetobacter sp. produced chitinase and Herbaspirillium sp. produced siderophore. Meanwhile, isolates of Anabaenopsis sp. and Pseudomonas sp. were the most effective to produce β 1,3glucanase and indole acetic acid compared with other entophytic bacteria

SUSCEPTIBILITY OF SOME TOMATO CULTIVARS TO BACTERIAL CANKER AND SPOT DISEASES AND THE ROLE OF SEEDS IN PATHOGEN TRANSMISSION*

Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Smith) and bacterial spot caused by Xanthomonas campestris pv. vesicatoria (Doidge) Dye have become important diseases of tomato in Egypt. The present work was planned to evaluate the reaction of different tomato cultivars and the role of seeds to transmit both pathogens. Cultivars of Dora, Flora-Dade, KTM141, Money Maker, Niagra, Super strain B hybrid and GS12 were moderately resistant to both diseases, but Castle rock, Peto 86 and Super strain B cultivars were susceptible. However, Castle rock, Peto 86, Super strain B and Niagra cultivars were highly susceptible for bacterial canker than spot disease. Using the Liquid assay method, C. michiganensis subsp. michiganensis bacterium could be detected in seeds of cultivars Dora, KTM141, Niagra and Super strain B hybrid, but X. campestris pv. vesicatoria was detected on seeds of cultivars GS12, Peto 86 and Super Marmand. However, both bacterial pathogens were not detected in seeds of all cultivars, except GS12, when direct planting method on selective media was used. In an in vivo assay, bacterial canker has developed more than bacterial spot disease on tomato seedlings produced from non-treated seeds. Bacterial canker has developed on all tested cultivars at different frequencies. Transmission of both pathogens occurred at high frequency by seeds of cultivars Niagra and Dora, however bacterial spot was not borne on samples of other tomato cultivar

نتائج جديدة بطريقة البوتاسيوم / ارجون لعمر الصخور البركانية بجزيرة حالول - قطر

The only rocks of igneous origin known to be exposed in Qatar are those of Halul and Shra'Auh Islands. They occur within a salt diapir and the age of these rocks is uncertain. They have generally been assigned to the Hormuz Formation; approximately Middle Cambrian age. A few unreliable isotopic ages were obtained earlier and led to inconclusive results. In this paper, new K/Ar ages obtained by the writer are presented and discussed. They indicate a tectono-thermal event which took place some 33 million years ago, although the rocks themselves are considered to be much older.تتواجد في جزيرتي حالول وشراعوه بعض الصخور البركانية هي الصخور الوحيدة من أصل ناري الموجودة على السطح في قطر . ويتناول هذا البحث عمر الصخور البركانية بجزيرة حالول كجزء أولي من دراسة بترولوجية تفصيلية لهذه الصخور -وقد سبقت محاولات قليلة لتحديد عمر هذه الصخور بطرق النظائر المشعة ولم تصل إلى نتائج يعتمد عليها- وفي هذا البحث تم الحصول على نتائج جديدة بطريقة البوتاسيوم /أرجون - تتراوح بين 29 -23 مليون سنة وتم مناقشتها في ضوء المعلومات الجيولوجية المتاحة عن هذه الصخور

النشاط الناري خلال حقب الحياة القديمة (الباليوزوي) في مصر

Based on available isotopic age data, including a few K/Ar ages obtained by the writer, a geochronological sequence of the main phases of igneous activity in Egypt during the Paleozoic is presented. Five main phases at around 550-500 Ma, 400 Ma, 350 Ma, 290 Ma and 230 Ma are identified. An attempt is made to relate these phases with tectonic events. It appears that Paleozoic igneous activity in Egypt was more widespread than has previously been recognised.استنادا إلى نتائج تعيين أعمار الصخور النارية المختلفة بطرق النظائر المشعة – يقدم هذا البحث تتابعا زمنيا يوضح المراحل الرئيسية للنشاط الناري في مصر خلال حقب الحياة القديمة ( الباليوزوي) – والمراحل الرئيسية التي تم تحديدها هي: 550 – 500 مليون سنة ، 400 مليون سنة ، 350 مليون سنة ، 290 مليون سنة ، 230 مليون سنة. ويتضح من هذه الدراسة أن النشاط الناري في الباليوزوري هو أكثر انتشارا عما كان معروفا عنه قبل

النشاط الناري في مصر خلال حقب الميزوزي

A geochronological sequence of the main phases of igneous activity in Egypt during the Mesozoic is presented in this paper. This is essentially based on scrutinized isotopic age data. New K / Ar ages are also included. Three main phases are outlined: 1. Early Triassic- Late Permian (230 ± 10 Ma). 2. Late Jurassic - Early Cretaceous (140 ± lOMa). 3. Late Cretaceous (90 * lOMa). An attempt is made to relate these phases with tectonic events.يقدم هذا البحث تتابعا زمنيا للمراحل الرئيسية للنشاط الناري في مصر خلال حقب الحياة المتوسطة ( الميزوزوي ) ، ويستند هذا التتابع بالدرجة الأولى على نصائح تعيين أعمار الصخور بطرق النظائر المشعة ، ويتضمن البحث نتائج جديدة بطريقة البوتاسيوم – آرجون . والمراحل الرئيسية التي تم تحديدها هي : 1- نهاية البرمي - الترياس المبكر (230 ± 10 مليون سنة) 2- نهاية الجوري - الكريتاوي المبكر (140 ± 10 مليون سنة) 3- الكريتاوي المتأخر (90 ± 10 مليون سنة) ويتضن البحث أيضا الربط بين هذه المراحل والأحداث التكتونية المصاحبة لها

نشأة وعمر الصخور الجرانيتية المتداخلة بجبل كوليت وسيجه جنوب الصحراء الشرقية بمصر

In the South Eastern Desert of Egypt tonalite. granodiorite and granite intruded intermediate to acidic metavolcanics and volcanogenic metasedimentary rocks of Precambrian age. The geological features of these granitic masses were investigated and a geological map (scale 1 : 40 000) was prepared. They have been classified into two groups: tonalite and granodiorite (syn to late-tectonic), and biotite and Muscovite granites (younger granitoids). The two groups appear to be genetically related on the basis of their major and trace element contents. The chemical compositions of these tonalitic to granitic rocks indicate that these granitic rocks belong to calc-alkaline series. The magma, during crystallisation, was under 3-4 kb pressure. Radiometric age determination indicates that they have a Pan-African age of 589 to 603 Ma. It is believed that these granitic intrusions have been intruded directly after the tectonic modification of an island arc.يقع جبل سيجه وجبل كوليت في جنوب الصحراء الشرقية بمصر، وهما يمثلان بكتل جرانيتية يتراوح تركيبها من صخور التوناليت إلى صخور الجرانيت متداخلة في صخور بركانية متوسطة وحمضية. تم رسم خريطة جيولوجية للمنطقة مقياس 40000:1 وقسمت هذه الصخور إلى مجموعتين الأولى صخور التوناليت والجرانوديوريت ، والثانية صخور الجرانيت الممثلة بالبيوتيت جرانيت والمسكوفيت جرانيت . وقد اتضح من الدراسة البتروجرافية والكيميائية وجود علاقة بين المجموعتين من حيث النشأة والتطور الصهيري وأنهم يتبعون مجموعة الصخور الكلس قلوية ، وتد تبلورت هذه الصخور تحت ضغط متوسط أثناء تكون أقواس الجزر . ومن تقدير عمر صخور المسكوفيت جرانيت بطريقة البوتاسيوم / أرجون ، اتضح أن عمرها يتراوح بين 589 و 602 مليون سنة