Samah Mokbel: Spiroplasma citri on Chili Pepper Plant in Egypt

Studies of Spiroplasma citri on Chili Pepper Plant in Egypt

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT

Spiroplasma citri was detected in naturally infected chili pepper plant in Kafer Ghatatty, Giza

governorate. Stunting, leaf deformation and shoot proliferation were naturally observed in this field. Hand cross section of chili pepper infected stem treated with Dienes’ stain by light microscopy showed phloem with blue stain while the healthy one remained unstained. Enzyme linked immunosorbent assay (ELISA) technique gave positive reaction of S. citri in natural infected samples using speciefic antiserum. Injection of healthy seedlings of chili pepper plant with liquid culture media of S.citri showed the similar symptoms appeared by natural infection. The injected seedlings and seeds resulted from it were tested by ELISA gave positive reactions of S.citri for both of them. These infected seeds are able to transmit S.citri easily among the plant. To our knowledge, this is the first record of S.citri infecting chili pepper plant in Egypt.

Key words: Spiroplasma citri, chili pepper, light microscopy, Dienes' stain, ELISA

How to cite this article:

Saied, S.M., EL-Abagy, E.M. and Mokbel, A.S. (2014). Studies of Spiroplasma citri on Chili Pepper Plant in Egypt. Middle East J.of Agriculture Research, 3(4): 968-972. http://www.curresweb.com/mejar/2014/968-972.pdf. 

Samah Mokbel: Antiviral activity of lactoferrin

Antiviral activity of lactoferrin against Potato virus x

in vitro and in vivo

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT

The effectiveness of lactoferrin against Potato virus x (PVX) in vitro and in vivo have been evaluated. Four concentrations of lactoferrin 100, 250, 500 and 1000 mg/L were examined either in vitro culture medium or in vivo (greenhouse). The presence of the virus was evaluated by ELISA technique. Results demonstrated that application of 1000 mg/L lactoferrin by spraying or combined with tissue culture proved to be an effective method for PVX-inhibition as compared with other concentrations. Also, results of antiviral activity of lactoferrin at concentration 1000 mg/L showed great potential as phytotherapeutic source to produce quality and health plantlets for rapid and large scale in vitro production.

Keywords: Lactoferrin; Potato virus x; Tissue culture; Greenhouse; Antiviral activity

 How to cite this article:

Taha, S.H., Mokbel, A.S., Abdel-Hamid, M. and Hamed, A.H. (2015). Antiviral activity of lactoferrin against Potato virus x in vitro and in vivo. Int. J. of Dairy Science, 10: 86-94.

http://scialert.net/abstract/?doi=ijds.2015.86.94

Samah Mokbel: Production of OYDV-free onion plantlets

Characterizations of the Egyptian isolate of Onion yellow dwarf virus Infecting onion and development of Virus-Free plantlets

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT

Onion yellow dwarf disease is an economically important disease of onion (Allium cepa L.) caused by Onion yellow dwarf virus (OYDV). In this research we aimed to identify and molecularly characterize the isolate of the OYDV infecting onion plants in Egypt and to obtain OYDV-free plants from infected onions through tissue culture techniques. To achieve our aim, the virus has been isolated from naturally infected onion plants grown in five Egyptian Governorates, Gharbia, Qalyobia, Giza, Fayoum and Beni-Suef then mechanically transmitted onto healthy onion plants in an insect proof greenhouse. The virus identification was done by indirect ELISA using specific antiserum and confirmed by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) using virus-specific primers. The molecular characterization for the Egyptian isolate has been performed through cloning and sequencing for the OYDV CP gene which amplified by RT-PCR then cloned and sequenced in the TOPO cloning vector. The CP gene sequence has been submitted to the GenBank and compared to other available isolates of OYDV. Sequence alignment and phylogenetic analysis showed that the Egyptian isolate of the OYDV is related to other isolates from Poland and Japan with a similarity ranged from 70 to 93% among those isolates available on GenBank. The virus was eliminated from infected onion plants using cytokinin (kinetin) in a tissue culture line to obtain the OYDV-free plantlets. The effect of different concentration levels of kinetin as well as its efficacy on the OYDV elimination and regeneration of infected onion bulbs were determined.

Key words: Onion, Onion yellow dwarf virus, cloning, RT-PCR, ELISA, Tissue culture, Cytokinin.

How to cite this article:

El-Attar A.K., Mokbel, A.S. and Hamed, A.H. (2014). Characterizations of the Egyptian isolate of Onion yellow dwarf virus Infecting Onion and development of Virus-free plantlets. Egyptian J. of Virology, 11(2): 68-81.

Samah Mokbel: Production of virus-free minitubers

Eradication of potato viruses and evaluation of different soil mixtures on minitubers production

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT: 

Recently production of virus-free potato minitubers is critical. For this purpose, infected tubers with Potato leafroll virus (PLRV) or Potato virus x (PVX) from two cultivars Spunta or Lady Rosette as demonstrated by serological detection were used as a source for virus-free minitubers production. This achived by subjecting tubers directly to thermotherapy treatment at 36ºC, 37ºC or 38ºC for three weeks which resulting in 50%, 70% or 80% of PLRV-free tubers and 0%, 16.6% or 33.3% of PVX-free tubers, respectively. Moreover, no effect on the survival rate of tubers was detected. High percentage of PLRV- or PVX-free plantlets (93.1% or 76%), respectively was achieved with meristem tip excision (0.1-0.2mm) from thermo-treated tubers at (38ºC) with survival rate 96.6% or 83.3%, respectively. DAS-ELISA method was applied to the tubers directly, in vitro cultures and young acclimatized plantlets to detect these viruses, after direct transplant of in vitro virus-free plantlets in greenhouse. The statistical analysis showed that cultivars and ratio of bed components and their interaction had insignificant (P>0.05) effects on minituber number and minituber weight. However, ratio of bed components and interaction with cultivars were significantly (P<0.05) affected on minituber diameter. Maximum minituber diameter (13.64 mm) was recorded for Lady Rosette cultivar, followed by Spunta cultivar (13.53 mm) applied with Vermiculite + Sand (4:1). Pots received Vermiculite + Sand (4:1), produced highest minituber diameter, while the least minituber was recorded for pots having Peat moss + Sand (4:1).

Key Words: Potato, PLRV, PVX, thermotherapy, meristem culture, minitubers, soil mixture.

How to cite this article:

Mokbel, A.S., and Abd El-Mohsen, A.A. (2014). Eradication of potato viruses and evaluation of different soil mixtures on minitubers production. Egyptian J. of Virology, 11(2):46-57.

Samah Mokbel: PRUNUS NECROTIC RINGSPOT VIRUS ON APPLE IN EGYPT

PARTIAL CHARACTERIZATION OF PRUNUS NECROTIC RINGSPOT VIRUS ON APPLE IN EGYPT

 Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

Abstract                                                        

A severe isolate of Prunus necrotic ringspot virus (PNRSV) was isolated from apple orchards in the vicinity of Nubaria city, Beheira governorate, Egypt. Infected-apple trees showed chlorotic, necrotic ringspots, and shoot holes on leaves. Severely infected- trees withered, became useless, and were removed causing severe economic losses.  Reverse transcriptase (RT) polymerase chain reaction (PCR), RT-PCR, using degenerate primer pair for the coat protein (CP) gene of Ilarvirus amplified products similar to those produced from peach and apricot isolates of PNRSV-infecting stone fruits) .  Dot blotting immuno-binding assay (DBIA showed positive reaction between PNRSV-infected apple sap and an Egyptian antiserum for PNRSV. Purified preparation from infected leaves, using the electro-elution technique yielded nucleoprotein which had A_max and A_min at 260 and 240 nm respectively. Electron microscopy examination showed spherical virions with ca. 26 nm in diameter.

 

Key words: Prunus necrotic ringspot virus, Ilarvirus, RT-PCR, Dot blotting immuno-binding assay, Egypt

How to cite this article:

Abdel-Salam, A.M. and Mokbel, A.S. (2014). Partial characterization of Prunus necrotic ringspot virus on apple in Egypt. Egyptian J. of Virology, 11(2): 280-287.

Samah Mokbel:Effectiveness of radiation processing in elimination of phytoplasma from in vitro plantlets

Effect of Gamma Irradiation on Production of Phytoplasma-Free Hibiscus Plantlets

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT:

Controlling phytoplasma-causing disease through combination of tissue culture technique and radiation treatment represented a short method for high level management. To investigate the effect of gamma rays to produce healthy plantlets, the hibiscus witches' broom phytoplasma was transmitted by grafting into healthy hibiscus plants, the in vitro-infected hibiscus explants were exposed to gamma radiation at different doses - 5 gray  (Gy), 10Gy, 15Gy, 20Gy and 25 Gy- emitted from cobalt 60 (⁶⁰Co) for 30 minute. All applied doses resulted in phytoplasma-free hibiscus plantlets with different survival activity. The presence of phytoplasma 16Sr DNA was examined using PCR detection before and after treatments. The different treatments of radiation resulted in different survival rates and phytotoxic effects including leaf yellowing and lack of growth. The 5Gy dose was proved to be best effective dose for controlling the phytoplasma without affecting the in vitro growth and survival rate, while the higher doses leaded to strongly reducing the survived hibiscus explants with increasing the inability to re-shoot.

Keywords: Hibiscus, phytoplasma, gamma irradiation, in vitro, PCR, graft transmission, tissue culture.

How to cite this article:

Mokbel, A.S. and El-Attar, A.K.  (2014). Effect of Gamma Irradiation on Production of Phytoplasma-Free Hibiscus Plantlets. Egyptian J. of Virology, 11(2): 35-45.

Samah Mokbel:First Record of a Witches'-Broom Phytoplasma Infecting Tomato in Egypt

Occurrence, Etiology and Molecular Characterization of phytoplasma diseases on Solanum lycopersicum crop in Egypt

Samah A. Mokbel

Department of Virus and Phytoplasma Research, Plant Pathology Research Institute, Agricultural Research Center., Egypt. Dr.SamahMokbel@gmail.com

ABSTRACT: Surveys were carried over the course of the 2012 and 2013 in different areas of tomato-growing fields in Egypt (Giza, Ismailia, Bani-Sweif, Fayoum and Qena) in order to determine the occurrence and distribution of phytoplasma associated with diseased tomato plants (Solanum lycopersycum L.), and to identify and classify the phytoplasma involved. A detection survey of infected tomato plants, which showed symptoms of big bud, witches'-broom and phyllody, in all regions of the screened governorates, reacted positively when assayed by nested polymerase chain reactions (PCR) using universal phytoplasma-specific primer pair P1/P7 and R16F2n/R16R2. Similar assays were used to detect phytoplasma interactions with experimentally host plant. Dienes’ stain was also used for detection of natural infection of phytoplasma. The phloem of infected tissues showed scattered area stained bright blue. Different techniques for transmission of phytoplasma to healthy tomatoes and periwinkles in an insect-proof greenhouse were tested, including mechanical inoculation, wedge grafting, parasitic plant dodder (Cuscuta campestris), insects in the family Cicadellidae (leafhopper, Empoasca decipiens) and in germinated seeds within the fruit, suggesting mechanical inoculation and seed-transmissible were not feasible while the positive results were obtained by the other three techniques for host plants with numerous symptoms obtained later. Application of transmission electron microscopy (TEM) technique for detection of experimentally inoculated samples, revealed phytoplasma in the phloem of most of tested samples. Phytoplasma were observed as rounded bodies, ranging in size from 200 to 600 nm. The molecular characterization was performed for three different samples representing the different symptoms of phytoplasma through cloning and direct sequencing. The DNA sequencing, phylogenetic analysis and the multiple alignments for the sequences of the Egyptian clones with each other and with the other sequences of phytoplasma strains on GenBank suggested that we may have three different phytoplasma isolates (witches’ broom, phyllody and big bud) infecting tomato plants in Egypt and listed under accession numbers KT225548, KT230865 and KT225545, respectively.

Key words: Phytoplasma, PCR, Sequencing, Dienes’stain, TEM, graft, dodder and insect transmission.

How to cite this article:

Ahmed, A.E., Shalaby, O.Y., Dwidar, E.F., Mokbel, A.S. and El-Attar, A.K. (2014). Occurrence, Etiology and Molecular Characterization of phytoplasma diseases on Solanum lycopersicum crop in Egypt. Egyptian J. of Virology, 11(2): 244-261.