Abstract:

In order to acquire a better insight into the ethylene and lipoxygenase control of flavour
compound generation and links between these metabolites and the central regulators of ripening，five
pleiotropic mutant tomato lines were subjected to volatile metabolite profiling in comparison with
wild-type Ailsa Craig（AC）. Five tomato mature mutants rin，nr，nor，cnr，hp-1 and wild type AC were
sampled at breaker color（0 d），three days after breaker（3 d）and seven days after breaker（7 d），
respectively. Aroma，ethylene and gene expression of hydroperoxide lyase（HPL），lipoxygenase（LOX）
activity and gene expression of TomloxC were investigated. With fruits growth and development，compared with the control，the aroma compounds in the mutant fruits were decreased. LOX enzyme activity and gene
expression of TomloxC were lower in rin，nor，cnr fruits than that in wild-type AC fruits. However，
expression of TomloxC were significantly increased in the hp-1 fruits and nr fruits at seven days after
breaker. The aroma compounds in ripening mutants of tomato were less than those in wild type，and they
can’t synthesize ethylene or synthesize small amounts of ethylene. Along with fruits growth and
development，the expression of LeHPL in AC and hp-1 were increased，seven days after breaker were
significantly higher than breaker and three days after breaker in the nor fruits，in rin and nr fruits were
significantly decreased at seven days after breaker. Above all，in the mutants lack of ethylene，the aroma
contents and types were lower than those in wild type，the ethylene synthesis were inhibited，LOX activity
and gene expression of LeHPL，TomloxC were decreased. Those results indicated that LOX was regulated
by ethylene in aroma volatiles synthesis of fruits.

Key words: tomato, mutant, lipoxygenase, ethylene, aroma volatile