Plant Viruses

During the past few years, many new virus diseases have been described, some of great economic importance and some with novel kinds of symptoms; much has been done on the factors that affect spread; and insect vectors have been identified in species of insects previously not incriminated. Plant viruses are viruses that infect plants. A virus particle, also known as a virion, is an extremely small infectious agent. It is essentially a nucleic acid (DNA or RNA) enclosed in a protein coat called a capsid. Viral genetic material can be double-stranded DNA, double-stranded RNA, single-stranded DNA or single-stranded RNA. Most plant viruses are classified as single-stranded RNA or double-stranded RNA virus particles. Very few are single-stranded DNA and none are double-stranded DNA particles. Viruses do not capture or store free energy and are not functionally active outside their host. They are therefore parasites but are not usually regarded as genuine microorganisms. This book is an excellent reference, providing insight into the exciting research developments made in the field.