The Tobacco mosaic virus replicase protein disrupts the localization and function of interacting Aux/IAA proteins.
Previously, we identified a correlation between the interaction of the Tobacco mosaic virus (TMV) 126/183-kDa replicase with the auxin response regulator indole acetic acid (IAA)26/PAP1 and the development of disease symptoms. In this study, the TMV replicase protein is shown to colocalize with IAA26 in the cytoplasm and prevent its accumulation within the nucleus. Furthermore, two additional auxin (Aux)/IAA family members, IAA27 and IAA18, were found to interact with the TMV replicase and displayed alterations in their cellular localization or accumulation that corresponded with their ability to interact with the TMV replicase. In contrast, the localization and accumulation of noninteracting Aux/IAA proteins were unaffected by the presence of the viral replicase. To investigate the effects of the replicase interaction on Aux/IAA function, transgenic plants expressing a proteolysis-resistant IAA26-P108L-green fluorescent protein (GFP) protein were created. Transgenic plants accumulating IAA26-P108L-GFP displayed an abnormal developmental phenotype that included severe stunting and leaf epinasty. However, TMV infection blocked the nuclear localization of IAA26-P108L-GFP and attenuated the developmental phenotype displayed by the transgenic plants. Combined, these findings suggest that TMV-induced disease symptoms can be attributed, in part, to the ability of the viral replicase protein to disrupt the localization and subsequent function of interacting Aux/IAA proteins.
Padmanabhan
Meenu S
MS
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
Shiferaw
Haiymanot
H
Culver
James N
JN
D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000032:analysis; D007210:Indoleacetic Acids / Q000032:analysis / Q000378:metabolism; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000378:metabolism / Q000821:virology; D010940:Plant Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000032:analysis; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000378:metabolism / Q000472:pathogenicity*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D000073718:Pancreatitis-Associated Proteins; D010940:Plant Proteins; C000612141:REG3A protein, human; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; C030737:indoleacetic acid