Kd. Kausch et Ak. Handa, MOLECULAR-CLONING OF A RIPENING-SPECIFIC LIPOXYGENASE AND ITS EXPRESSION DURING WILD-TYPE AND MUTANT TOMATO FRUIT-DEVELOPMENT, Plant physiology, 113(4), 1997, pp. 1041-1050
A 94-kD protein that accumulates predominately in tomato (Lycopersicon
esculentum) fruit during ripening was purified, and antibodies specif
ic for the purified protein were used to isolate cDNA clones from a re
d-ripe fruit cDNA library. A sequence analysis of these cDNAs and cros
s-reactivity of the 94-kD-specific antibodies to the soybean lipoxygen
ase (LOX) L-1, L-2, and L-3 proteins and soybean LOX L-1-specific anti
bodies to the 94-kD protein identified it as a member of the LOX gene
family. Maximum levels of the 94-kD LOX mRNA and protein are present i
n breaker to ripe and red-ripe stages, respectively. Expression of 94-
kD LOX in different tissues from mature green and red-ripe tomato frui
ts was found to be greatest in the radial walls of ripe fruit, but imm
unocytolocalization using tissue printing suggests that the highest ac
cumulation of its protein occurs in locular jelly. None of 94-kD LOX i
s expressed in nonripening mutant fruits of any age. Never-ripe mutant
fruit accumulate the 94-kD LOX mRNA to levels similar to those obtain
ed in wild-type fruit, but fail to accumulate the 94-kD LOX protein. C
ollectively, the results show that expression of 94-kD LOX is regulate
d by the ripening process, and ethylene may play a role in its protein
accumulation.