All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.
What are the main characteristics of a plant virus?
Virus is a submicroscopic, transmissible, intercellular, obligate parasite and consists of nucleic acid (either RNA or DNA), which is typically surrounded by a protein coat. They are less than 200 millimicron and cannot be grown in artificial media and require living host cell for multiplication.
What is the structure and genome of a typical plant virus?
Viruses are the smallest among all known organisms. The typical diameter of a spherical plant virus is ~30 nm. The rigid, rod-shaped TMV particle is 300 x 18 nm and consists of an RNA genome of about 6,400 nucleotides encapsidated by 2,130 copies of the TMV coat protein.
What is the structure of a virus where do they come from?
A complete virus particle, known as a virion, consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres. Viruses can have a lipid “envelope” derived from the host cell membrane.
What is the shape and structure of a virus?
Most viruses have icosahedral or helical capsid structure, although a few have complex virion architecture. An icosahedron is a geometric shape with 20 sides, each composed of an equilateral triangle, and icosahedral viruses increase the number of structural units in each face to expand capsid size.
What structure gives a virus its shape?
Shapes of viruses are predominantly of two kinds: rods, or filaments, so called because of the linear array of the nucleic acid and the protein subunits; and spheres, which are actually 20-sided (icosahedral) polygons.
How do viruses infect plant cells?
Some viruses can infect plants when aphids and other insects tap into the phloem to feed. Such insect vectors can also pick up virus particles and carry them to new plant hosts. Other viruses infect plant cells through a wound site created by a leaf-munching insect such as a beetle.
What are plant viruses called?
INTRODUCTION
| Rank | Virus | Author of virus description |
|---|---|---|
| 1 | Tobacco mosaic virus (TMV) | Karen-Beth G. Scholthof |
| 2 | Tomato spotted wilt virus (TSWV) | Scott Adkins |
| 3 | Tomato yellow leaf curl virus (TYLCV) | Henryk Czosnek |
| 4 | Cucumber mosaic virus (CMV) | Peter Palukaitis |
Which of the plant virus contain DNA as genome?
Geminiviruses, a newly discovered group of plant viruses, have single-stranded circular DNA in their genome. The nucleocapsids are isometric units bonded together in pairs. Geminiviruses are among the smallest autonomously replicating viruses known so far.
How does the structure of a virus differ from that of a cell?
Cells have a double stranded DNA molecule and many strands of single stranded RNA as the copies. Viruses, however, can have double stranded DNA, single stranded DNA, double stranded RNA, or single stranded RNA. They convert RNA to DNA and then back to RNA to make proteins, which does not happen inside cells.
