title: Tomato plant cell death induced by inhibition of HSP90 is alleviated by Tomato yellow leaf curl virus infection.
abstract: To ensure a successful long-term infection cycle, begomoviruses must restrain their destructive effect on host cells and prevent drastic plant responses, at least in the early stages of infection. The monopartite begomovirus Tomato yellow leaf curl virus (TYLCV) does not induce a hypersensitive response and cell death on whitefly-mediated infection of virus-susceptible tomato plants until diseased tomatoes become senescent. The way in which begomoviruses evade plant defences and interfere with cell death pathways is still poorly understood. We show that the chaperone HSP90 (heat shock protein 90) and its co-chaperone SGT1 (suppressor of the G2 allele of Skp1) are involved in the establishment of TYLCV infection. Inactivation of HSP90, as well as silencing of the Hsp90 and Sgt1 genes, leads to the accumulation of damaged ubiquitinated proteins and to a cell death phenotype. These effects are relieved under TYLCV infection. HSP90-dependent inactivation of 26S proteasome degradation and the transcriptional activation of the heat shock transcription factors HsfA2 and HsfB1 and of the downstream genes Hsp17 and Apx1/2 are suppressed in TYLCV-infected tomatoes. Following suppression of the plant stress response, TYLCV can replicate and accumulate in a permissive environment.
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Moshe
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Rena
authors.initials: R
authors.lastname: Gorovits
authors.affiliation: School of Life Sciences, Tsinghua University, Beijing, 100084, China.
authors.forename: Yule
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Henryk
authors.initials: H
authors.lastname: Czosnek
mesh_terms: D053839:Begomovirus / Q000472:pathogenicity*; D036022:Capsid Proteins / Q000378:metabolism; D016923:Cell Death; D020868:Gene Silencing; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006358:Hot Temperature; D018551:Solanum lycopersicum / Q000166:cytology* / Q000821:virology*; D008954:Models, Biological; D059828:Plant Cells / Q000821:virology*; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000166:cytology / Q000821:virology; D010940:Plant Proteins / Q000378:metabolism*; D066329:Protein Aggregates; D054875:Ubiquitination
chemical_list: D036022:Capsid Proteins; D018841:HSP90 Heat-Shock Proteins; D010940:Plant Proteins; D066329:Protein Aggregates; D049452:Green Fluorescent Proteins
keywords: HSP90; cell death; geminivirus; heat stress transcription factor