Most plant reoviruses encode a type of nonstructural protein that assembles tubular structures to package virions for viral spread in planthopper or leafhopper vectors.These tubules are propelled by actin filaments an...Most plant reoviruses encode a type of nonstructural protein that assembles tubular structures to package virions for viral spread in planthopper or leafhopper vectors.These tubules are propelled by actin filaments and facilitate viruses to overcome transmission barriers in insect vectors.This is known as actin-based tubule motility(ABTM),in which insect proteins,especially actin-associated proteins participate.To better understand the insect components that play a role in the ABTM,the proteins interacting with tubule protein Pns11 of the Rice gall dwarf virus(RGDV)in the leafhopper vector were investigated.We found that gelsolin,an actin-modulating protein,interacted with Pns11 in the yeast-two-hybrid system and Sf9 cells.The interaction and co-localization of gelsolin and Pns11 were also verified in cultured cells and insect bodies of the leafhopper vector.Further,the expression of gelsolin was up-regulated by the RGDV infection both in cultured cells and insects.The knockdown of the gelsolin gene triggered by RNA interference increased viral accumulation,thus increasing the viruliferous rates of the leafhopper vector.This negative association of gelsolin with Pns11 and virus infection revealed that gelsolin negatively affected the ability of the virus to spread by interacting with Pns11 tubules,finally acting to negatively regulate RGDV infection.The results of this study indicate that ABTM is negatively regulated by insects in the coevolution of the insect vector and virus.展开更多
RNA silencing is a potent antiviral mechanism in plants and animals. As a counter-defense, many viruses studied to date encode one or more viral suppressors of RNA silencing(VSR). In the latter case, how different VSR...RNA silencing is a potent antiviral mechanism in plants and animals. As a counter-defense, many viruses studied to date encode one or more viral suppressors of RNA silencing(VSR). In the latter case, how different VSRs encoded by a virus function in silencing remains to be fully understood. We previously showed that the nonstructural protein Pns10 of a Phytoreovirus, Rice dwarf virus(RDV), functions as a VSR. Here we present evidence that another nonstructural protein, Pns11, also functions as a VSR. While Pns10 was localized in the cytoplasm, Pns11 was localized both in the nucleus and chloroplasts. Pns11 has two bipartite nuclear localization signals(NLSs), which were required for nuclear as well as chloroplastic localization. The NLSs were also required for the silencing activities of Pns11. This is the first report that multiple VSRs encoded by a virus are localized in different subcellular compartments, and that a viral protein can be targeted to both the nucleus and chloroplast. These findings may have broad significance in studying the subcellular targeting of VSRs and other viral proteins in viral-host interactions.展开更多
基金supported by the National Natural Science Foundation of China under grant numbers 3173007131772124+2 种基金the Natural Science Foundation of Fujian Province,China under grant number 2017 J06011the National Key R&D Program of China under grant number 2017YFD0200900the Program for New Century Excellent Talents in Fujian Province University under grant number Kla18057A.
文摘Most plant reoviruses encode a type of nonstructural protein that assembles tubular structures to package virions for viral spread in planthopper or leafhopper vectors.These tubules are propelled by actin filaments and facilitate viruses to overcome transmission barriers in insect vectors.This is known as actin-based tubule motility(ABTM),in which insect proteins,especially actin-associated proteins participate.To better understand the insect components that play a role in the ABTM,the proteins interacting with tubule protein Pns11 of the Rice gall dwarf virus(RGDV)in the leafhopper vector were investigated.We found that gelsolin,an actin-modulating protein,interacted with Pns11 in the yeast-two-hybrid system and Sf9 cells.The interaction and co-localization of gelsolin and Pns11 were also verified in cultured cells and insect bodies of the leafhopper vector.Further,the expression of gelsolin was up-regulated by the RGDV infection both in cultured cells and insects.The knockdown of the gelsolin gene triggered by RNA interference increased viral accumulation,thus increasing the viruliferous rates of the leafhopper vector.This negative association of gelsolin with Pns11 and virus infection revealed that gelsolin negatively affected the ability of the virus to spread by interacting with Pns11 tubules,finally acting to negatively regulate RGDV infection.The results of this study indicate that ABTM is negatively regulated by insects in the coevolution of the insect vector and virus.
基金supported by grants from CARS-01-06 to X.H.X., Transgenic Research Program (2016ZX08010001)the National Natural Science Foundation of China (31530062)。
文摘RNA silencing is a potent antiviral mechanism in plants and animals. As a counter-defense, many viruses studied to date encode one or more viral suppressors of RNA silencing(VSR). In the latter case, how different VSRs encoded by a virus function in silencing remains to be fully understood. We previously showed that the nonstructural protein Pns10 of a Phytoreovirus, Rice dwarf virus(RDV), functions as a VSR. Here we present evidence that another nonstructural protein, Pns11, also functions as a VSR. While Pns10 was localized in the cytoplasm, Pns11 was localized both in the nucleus and chloroplasts. Pns11 has two bipartite nuclear localization signals(NLSs), which were required for nuclear as well as chloroplastic localization. The NLSs were also required for the silencing activities of Pns11. This is the first report that multiple VSRs encoded by a virus are localized in different subcellular compartments, and that a viral protein can be targeted to both the nucleus and chloroplast. These findings may have broad significance in studying the subcellular targeting of VSRs and other viral proteins in viral-host interactions.
