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V i r u s. Introduction to Plant Virology. Symptoms Virus structure Transmission Virus transport Biotechnology.
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V i r u s
Introduction to Plant Virology SymptomsVirus structureTransmissionVirus transportBiotechnology
Virus symptoms : Virus infected plants can display a wide range of different symptoms.The whole plant can be stunted (dwarf-like) and infected leaves can show abnormal colorations like mosaics and yellowing. Very often infected leaves have a rolling or curly appearance and also the fruits can display various symptoms dependent on the virus.The yield of crop plants can be severely reduced by a virus infection.However, the age of the plants, the viral strain and many other factors are affecting both yield and symptoms of infected plants.
Virus structure : Virus particles are so small that they can not be seen in a light microscope. However, by using an Electron Microscope (EM) it is possible to visualize virus particles. Dependent on the virus species the particles can have a number of different forms as shown to the right. Some viruses are surrounded by a lipid membrane (shown in blue).
Virus structure : All virus particles contain a virus genome (either DNA or RNA).The genome is surrounded by a large number of proteins (coat proteins) forming the outher shell of the virus particle. When detecting viruses by immunological methods (fx ELISA) it is the coat proteins of the virus that are detected. In contrast, the virus genome may be detected by PCR.
Virus transport : In order to spread in the plant viruses take advantage of the plants own transport system. This involves plasmodesmata connecting individual cells and the phloem vessels which can transport the virus to distant sites in the plant. However, virus particles (blue) cannot spread through the plasmodesmata unless these are modified by the virus.For this purpose plant viruses express various movement proteins (red) which increases the size of the plasmodesmata. Several different mechanisms seems to be involved in this process.
Contoh Penyakit Tanaman Karena Virus
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