RNA and capsid accumulation in cowpea protoplasts that are resistant to cowpea mosaic virus strain SB.
Leaf protoplasts from the Arlington line of cowpea (Vigna unguiculata) support only a limited increase of cowpea mosaic virus strain SB (CPMV-SB), whereas cowpea severe mosaic virus, another member of the comovirus group, replicates efficiently in Arlington cowpea protoplasts. CPMV-SB replicates efficiently in protoplasts of cowpea line Blackeye 5. Some characteristics of the virus-specific resistance of Arlington protoplasts to CPMV-SB are reported. Differences between progeny CPMV-SB from Arlington and Blackeye 5 protoplasts were not detected. Inoculation with CPMV-SB RNA, rather than virions, did not make Arlington protoplasts fully susceptible. These results favor, for likely involvement in the CPMV-SB restriction phenomenon, events in the virus life cycle that occur after exposure of virion RNA to the cytoplasm and before assembly of particles is completed. The accumulation of CPMV-SB RNAs of both polarities was found to be depressed in inoculated Arlington protoplasts. However, (+)RNA (virion RNA polarity) accumulated to no lesser extent, per unit of (-)RNA, in Arlington protoplasts than in Blackeye 5 protoplasts. Capsid antigen accumulation, per unit of (+)RNA, was reduced in Arlington protoplasts as compared to Blackeye 5 protoplasts. A working hypothesis consistent with the above and other observations is that Arlington protoplasts have an inhibitory substance that interferes with the production or/and function of CPMV-SB specified proteins.
D002213:Capsid / Q000235:genetics* / Q000302:isolation & purification; D003433:Crosses, Genetic; D007700:Kinetics; D009029:Mosaic Viruses / Q000235:genetics*; D010944:Plants / Q000235:genetics / Q000382:microbiology*; D011523:Protoplasts / Q000382:microbiology*; D012330:RNA, Double-Stranded / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D014771:Virion / Q000235:genetics
D012330:RNA, Double-Stranded; D012367:RNA, Viral