Cauliflower Mosaic Virus

Cauliflower mosaic virus

Host Range ► Narrow

host range ,restricted members of Brassicaceae

► Vein

clearin in Arabidopsis,Brassica spe,Rhaphanus sps &other plants family in Brassicaceae

Classification ► ► ► ► ► ► ►

The Caulimoviridae are a family of viruses, including the following genera: Genus Badnavirus; type species: Commelina yellow mottle virus Genus Caulimovirus; type species: Cauliflower mosaic virus Genus Tungrovirus; type species: Rice tungro bacilliform virus Genus Soymovirus; type species: Soybean chlorotic mottle virus Genus Cavemovirus; type species: Cassava vein mosaic virus Genus Petuvirus; type species: Petunia vein clearing virus

Structure ► Camv

is an icosahedral virus ► Diameter 50nm ,molecular weight 23*10(6) dal ► genome is circular ds DNA,present between ► 2 & 3 layers ► Molecular weight 4.9*10(6)dal ► G+C content 43% ► Capsid multilayered ► Arrangement of capsomere not clear

Structure

► The

(-)strand :single discontinuity or

gap ► The (+)strand:two gaps ► Gaps are primer binding sites for replication of DNA ► Gaps are same respect to specific restriction site

Properties ► Thermal

inactivation point 70 to 75 degree cell for 10 mint ► DNA resistant to chloroform ► Infectivity weakened by treatment with ether ► Linear DNA not infective ► Serological studies:closely related to dahila mosaic,straw berry banding and carnation etched ring viruses

Genome ► ► ► ► ► ► ►

Coding region I -  codes for 38 KD protein which helps in transfer of virus from one cell to another. Coding region II - codes for 19 KD protein which attracts aphids. Coding region III - codes for viral 15 KD viral capsomeres. Coding region IV - codes for 57 KD coat protein. Coding region V- codes for 79 KD reverse transcriptase Coding region VI - codes for 58 KD proteins which is used in building inclusion bodies. Coding region VII - codes for protein which targets newly formed virus to inclusion body.

Replication ► Enry

into the host cell by aphids ► Uncoating and release of DNA within cytoplasm ► Uncoated DNA transport to nucleus ► Removal of overhang and gaps by DNAse and DNAligase ► DNA associated with histones ► Two RNA transcripts produced and transported to cytoplasm

► 35sRNA

Codes structural proteins ► 19sRNA involved replication ► dsDNA synthesised from RNAs by reverse transcriptase ► Encapsidation occurs form progeny virion ► Newly formed virus aggregate form inclusion bodies ► Mature virions escape from infected

symptoms

Symptoms ► Vein

clearing or chlorotic vein banding in Arabidopsis thaliana,Brassica spe. ► Mosaic symptoms occur in B. campestris ► Stunting of entire plant ► Virus containing Inclusion bodies in the cytoplasm ► Nucleus become lobed ► vesicles protrude out from cell wall

Control ► Using

insecticides ► Elimination of disease plants ► Cultivation of virus –resistant varieties ► Selection of disease free planting materials ► Selection of disease free soil for cultivation

APPLICATIONS ►

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The cauliflower mosaic virus (CaMV) 35S promoter has been most commonly used in plant transformation studies, but its activity in mushrooms has not been reported. p301-b is a binary vector containing a bialaphos resistance gene driven by the promoter of Lentinus edodes glyceraldehyde-3-phosphate dehydrogenase (GPD) gene. CaMV 35S-GUS was inserted into p301-b, and the resulting construct p301-bG was transformed to protoplasts of Ganoderma lucidum and basidiospores of Pleurotus citrinopileatus. GUS activity was observed in the transformants, indicating that CaMV 35S promoter can direct expression of exogenous gene in the mushrooms. This is the first report on the application of CaMV 35S promoter in genetic modification of