Physicochemical properties of plant viruses?

in plant pathology

Physicochemical properties of plant viruses?microsoft office

Plant viruses, like all other viruses, are obligate intracellular parasites that do not have the molecular machinery to replicate without the host. The plant viruses are defined as viruses pathogenic to higher plants. While this article does not intend to list all plant viruses, it discusses some important viruses as well as their uses in plant molecular biology.Most of the virus types that have been discovered infecting plants are single-stranded RNA viruses, and have rod-shaped capsids with protein units arranged in a spiral.One novel characteristic of Plant viruses is that some of the viruses, instead of having a segmented genome packaged into the same particle as happens in animal viruses, some of the plant virus species are multipartite. This is when, for example, in the Gemini virus genome there is two incomplete icosahedral particles joined as a pair and can contain two circular single stranded DNA molecules. This has been suggested that this method employed by plant viruses of separately packaging the genome solves the problem of organisation and packaging problems associated with the segmented genome.There are two major ways the viral diseases may spread: horizontal transmission and vertical transmission. Horizontal transmission means that the infection comes from the outside, usually through damage done to the plant by vegetative propagation, grafting, vectors (some viruses can propagate in plant host and vector animal) or mechanical transmission. Vertical transmission refers to the plant inheriting the disease from a parent; this is often via seed but is not as prevalent as horizontal transmission. Plant viruses frequently have the ability to stunt growth and diminish crop yield.

The outer surfaces of plants are composed of protective layers of waxes and pectin, but more significantly, each cell is surrounded by a thick wall of cellulose overlying the cytoplasmic membrane.There are single stranded, double stranded RNA and single stranded, double stranded DNA plant virus.