INVERTEBRATE TISSUE-CULTURE AS A TOOL TO STUDY INSECT TRANSMISSION OF PLANT-VIRUSES

Invertebrate tissue culture is an underutilized resource in the study of insect-transmitted plant viruses. Since the establishment of leafhopper vector monolayers over 20 yr ago, these continuous cultures were used primarily to assay the infectivity of plant viruses that replicate in their insect vectors and to elucidate the viral determinants for transmission of wound tumor phytoreovirus and potato yellow dwarf rhabdovirus. Primary aphid cultures were used to study the uptake of viruses and viral accumulation. The biggest potential for use of insect cell culture in the future is in studying the molecular biology of propagative viruses. Although leafhopper cell lines do not support the same virus-vector specificity that is found in vivo, the cell lines have some advantage over the use of whole insects in the ease with which viral transcripts and mutant viruses can be uniformly introduced into cells. Existing leafhopper monolayer systems could facilitate studies on the influence of the vector's genetic background on viral replication. Cultures derived from salivary glands might be useful to study the insect receptors that recognize the viral capsid. Cell lines from planthoppers, thrips, and eriophid mite vectors would allow research on the biological and molecular characterization of poorly characterized plant viruses.