The role of alternative oxidase in tomato fruit ripening and its regulatory interaction with ethylene.
Although the alternative oxidase (AOX) has been proposed to play a role in fruit development, the function of AOX in fruit ripening is unclear. To gain further insight into the role of AOX in tomato fruit ripening, transgenic tomato plants 35S-AOX1a and 35S-AOX-RNAi were generated. Tomato plants with reduced LeAOX levels exhibited retarded ripening; reduced carotenoids, respiration, and ethylene production; and the down-regulation of ripening-associated genes. Moreover, no apparent respiratory climacteric occurred in the AOX-reduced tomato fruit, indicating that AOX might play an important role in climacteric respiration. In contrast, the fruit that overexpressed LeAOX1a accumulated more lycopene, though they displayed a similar pattern of ripening to wild-type fruit. Ethylene application promoted fruit ripening and anticipated ethylene production and respiration, including the alternative pathway respiration. Interestingly, the transgenic plants with reduced LeAOX levels failed to ripen after 1-methylcyclopropene (1-MCP) treatment, while such inhibition was notably less effective in 35S-AOX1a fruit. These findings indicate that AOX is involved in respiratory climacteric and ethylene-mediated fruit ripening of tomato.
Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University Chengdu 610064  China.
Fei
F
Xu
Shu
S
Yuan
Da-Wei
DW
Zhang
Xin
X
Lv
Hong-Hui
HH
Lin
D000255:Adenosine Triphosphate / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D019069:Cell Respiration; D003521:Cyclopropanes / Q000494:pharmacology; D015536:Down-Regulation; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D005638:Fruit / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D006856:Hydrogen Cyanide / Q000378:metabolism; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D000099188:Alternative Oxidase
D000255:Adenosine Triphosphate; D002338:Carotenoids; D003521:Cyclopropanes; D005030:Ethylenes; D006856:Hydrogen Cyanide; D000077276:Lycopene; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010937:Plant Growth Regulators; D010940:Plant Proteins; D000099188:Alternative Oxidase; C036216:ethylene; C412563:1-methylcyclopropene