MICR3002 Lecture Notes - Lecture 4: Cowpea, Microrna, Antisense Rna
Document Summary
Persistent: no obvious symptoms, maintains infection for lifetime of host, no mp, seed transmission entirely through gametes, no horizontal transmission, low titre, examples: partitiviridae family and endornavirus genus. Infection may be resolves by recovery: encodes mp, may or may not be seed transmitted via gametes (rarely at high frequency, horizontal transmission usually by insect vectors, high titre, majority of viruses and well studied. Immunity: no detectable virus replication, high level resistant. Resistance: various levels of symptoms, delayed symptoms, reduced symptom severity, etc, eg. local lesions. Tolerance: virus replicates, plants appear healthy. Control of plant viruses: plants have no immune system, no viricides exists, plants infected for life, viruses rarely kill their plant host, control = prevent infection. Types of control: hygiene measures, control of vectors, plant resistance genes (breeding, mild strain cross protection, genetic engineering for resistance. If infected with a mild strain, can"t be infected with a severe strain of the same virus: pre-inoculate with wild virus, genetic engineering.
