@article{pooma_gillette_jeffrey_petty_1996, title={Host and viral factors determine the dispensability of coat protein for bipartite geminivirus systemic movement}, volume={218}, ISSN={["0042-6822"]}, DOI={10.1006/viro.1996.0189}, abstractNote={Geminiviruses have unique, twinned icosahedral particles which encapsidate circular single-stranded DNA. Their genomes are composed of either one or two DNA segments. Monopartite geminiviruses absolutely require a functional coat protein (CP) for infectivity, whereas bipartite geminivirus CP null mutants can infect plants systemically. However, we show here that a CP mutant of the bipartite tomato golden mosaic virus (TGMV), which can infect Nicotiana benthamiana systemically, is confined to the inoculated leaves of Nicotiana tabacum or Datura stramonium. We also show that a CP mutant of the related bean golden mosaic virus (BGMV), which can infect beans systemically, is confined to the inoculated leaves of N. benthamiana. In each case, the extent of viral DNA accumulation in inoculated leaves was unaffected by the absence of CP, which suggests that CP is required specifically for systemic movement. The dispensability of CP is correlated with the degree of virus-host adaptation. TGMV is well adapted to N. benthamiana and does not require CP to infect this host systemically, whereas BGMV is poorly adapted to N. benthamiana and requires CP. Analysis of TGMV-BGMV hybrid viruses revealed that the viral genetic background can also affect the dispensability of CP for systemic movement in N. benthamiana. Thus, bipartite geminivirus movement in planta can be resolved genetically into three components: (i) local, cell-to-cell movement, which does not require CP; (ii) CP-dependent systemic movement, which occurs in all hosts tested; and (iii) CP-independent systemic movement, which occurs in hosts to which a given virus is well adapted.}, number={1}, journal={VIROLOGY}, author={Pooma, W and Gillette, WK and Jeffrey, JL and Petty, ITD}, year={1996}, month={Apr}, pages={264–268} }
 @article{pooma_petty_1996, title={Tomato golden mosaic virus open reading frame AL4 is genetically distinct from its C4 analogue in monopartite geminiviruses}, volume={77}, ISSN={["0022-1317"]}, DOI={10.1099/0022-1317-77-8-1947}, abstractNote={Tomato golden mosaic virus (TGMV) is a bipartite geminivirus with six well-characterized genes. An additional open reading frame (ORF), AL4, lies within the essential AL1 gene. Recent studies of monopartite, dicot-infecting geminiviruses have revealed that mutations in their analogous C4 ORFs have host-specific effects on infectivity, symptomatology, virus movement and/or viral DNA accumulation. We have investigated whether TGMV has a similar host-specific requirement for AL4. The phenotypes of three TGMV al4 mutants were determined in a range of hosts, which included species that revealed c4 mutant phenotypes for monopartite geminiviruses. Each TGMV al4 mutant was indistinguishable from wild-type TGMV in all hosts tested. Additional analyses of double mutants revealed no evidence for functional redundancy between AL4 and the AL3, or AR1 genes. In contrast to the putative C4 proteins of monpartite geminiviruses, TGMV AL4, if it is expressed, is either non-functional, or functionally redundant with an essential TGMV gene product.}, journal={JOURNAL OF GENERAL VIROLOGY}, author={Pooma, W and Petty, ITD}, year={1996}, month={Aug}, pages={1947–1951} }