The six Tomato yellow leaf curl virus genes expressed individually in tomato induce different levels of plant stress response attenuation.
Tomato yellow leaf curl virus (TYLCV) is a begomovirus infecting tomato plants worldwide. TYLCV needs a healthy host environment to ensure a successful infection cycle for long periods. Hence, TYLCV restrains its destructive effect and induces neither a hypersensitive response nor cell death in infected tomatoes. On the contrary, TYLCV counteracts cell death induced by other factors, such as inactivation of HSP90 functionality. Suppression of plant death is associated with the inhibition of the ubiquitin 26S proteasome degradation and with a deactivation of the heat shock transcription factor HSFA2 pathways (including decreased HSP17 levels). The goal of the current study was to find if the individual TYLCV genes were capable of suppressing HSP90-dependent death and HSFA2 deactivation. The expression of C2 (C3 and CP to a lesser extent) caused a decrease in the severity of death phenotypes, while the expression of V2 (C1 and C4 to a lesser extent) strengthened cell death. However, C2 or V2 markedly affected stress response under conditions of viral infection. The downregulation of HSFA2 signaling, initiated by the expression of C1 and V2, was detected in the absence of virus infection, but was enhanced in infected plants, while CP and C4 mitigated HSFA2 levels only in the infected tomatoes. The dependence of analyzed plant stress response suppression on the interaction of the expressed genes with the environment created by the whole virus infection was more pronounced than on the expression of individual TYLCV genes.
Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel. rena.gorovits@mail.huji.ac.il.
Rena
R
Gorovits
Department of Cell Research and Immunology, Tel-Aviv University, 69978, Ramat Aviv, Israel.
Adi
A
Moshe
Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
Linoy
L
Amrani
Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
Rotem
R
Kleinberger
Faculty of Agricultural Technology, Department of Biotechnology, Al-Balqa' Applied University, Al-Salt, 19117, Jordan.
Ghandi
G
Anfoka
Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
Henryk
H
Czosnek
D015100:3,3'-Diaminobenzidine / Q000737:chemistry; D053839:Begomovirus / Q000235:genetics* / Q000378:metabolism; D020868:Gene Silencing; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000032:analysis / Q000737:chemistry; D018551:Solanum lycopersicum / Q000378:metabolism* / Q000821:virology; D010781:Photography; D010935:Plant Diseases / Q000821:virology; D018515:Plant Leaves / Q000378:metabolism / Q000821:virology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D013696:Temperature; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D010940:Plant Proteins; D014764:Viral Proteins; D015100:3,3'-Diaminobenzidine; D006861:Hydrogen Peroxide
Cell death; Geminivirus; Stress response; Viral proteins