Systemic induction and role of mitochondrial alternative oxidase and nitric oxide in a compatible tomato-Tobacco mosaic virus interaction.
The role of mitochondrial alternative oxidase (AOX) and the relationship between AOX and nitric oxide (NO) in virus-induced systemic defense to Tobacco mosaic virus (TMV) were investigated in susceptible tomato (Solanum lycopersicum) plants. TMV inoculation to the lower leaves induced a rapid NO synthesis and AOX activation in upper uninoculated leaves as early as 0.5 day postinoculation. Application of exogenous potassium cyanide (KCN, a cytochrome pathway inhibitor) at nonlethal concentrations and NO donor diethylamine NONOate (DEA/NO) to the upper uninoculated leaves greatly induced accumulation of AOX transcript, reduced TMV viral RNA accumulation, and increased the leaf photochemical quantum yield at photosystem II. Pretreatment with NO scavenger almost completely blocked TMV-induced AOX induction and substantially increased TMV susceptibility. Salicylhydroxamic acid (SHAM, an AOX inhibitor) pretreatment reduced the DEA/NO-induced cyanide-resistant respiration and partially compromised induced resistance to TMV. Conversely, KCN and SHAM pretreatment had very little effect on generation of NO, and pretreatment with NO scavenger did not affect KCN-induced AOX induction and TMV resistance. These results suggest that TMV-induced NO generation acts upstream and mediates AOX induction which, in turn, induces mitochondrial alternative electron transport and triggers systemic basal defense against the viral pathogen.
Fu
Li-Jun
LJ
Department of Horticulture, Huajiachi Campus, Zhejiang University, P. R. China.
Shi
Kai
K
Gu
Min
M
Zhou
Yan-Hong
YH
Dong
De-Kun
DK
Liang
Wu-Sheng
WS
Song
Feng-Ming
FM
Yu
Jing-Quan
JQ
D000154:Aconitate Hydratase / Q000378:metabolism; D019069:Cell Respiration; D019343:Citric Acid / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D054884:Host-Pathogen Interactions; D018551:Solanum lycopersicum / Q000201:enzymology / Q000378:metabolism / Q000821:virology*; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism*; D010935:Plant Diseases / Q000821:virology; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism / Q000821:virology; D010940:Plant Proteins / Q000378:metabolism; D011190:Potassium Cyanide / Q000494:pharmacology; D013997:Time Factors; D014027:Tobacco Mosaic Virus / Q000502:physiology*; D000099188:Alternative Oxidase
D000154:Aconitate Hydratase; D019343:Citric Acid; D003576:Electron Transport Complex IV; D004791:Enzyme Inhibitors; D024101:Mitochondrial Proteins; D009569:Nitric Oxide; D010088:Oxidoreductases; D010940:Plant Proteins; D011190:Potassium Cyanide; D000099188:Alternative Oxidase