L. Trainotti et al., Two different endo-beta-1,4-glucanases contribute to the softening of the strawberry fruits, J PLANT PHY, 154(3), 1999, pp. 355-362
The expression of different endo-beta-1,4-glucanases (EGases) and the ultra
structural details of the cell wall dismantling were studied throughout the
development of the strawberry fruits. Detectable enzyme activity is first
observed in large green fruits, but a steep increase occurs in white fruits
when the ripening process proper starts. This process is then accompanied
by a further increase in EGase activity which appears to be doubled in red
ripe fruits. Two isoforms with different isoelectric points (pI 7.9 and 9.0
, respectively) contribute to the observed enzyme activity, and both isoenz
ymes increase in activity as fruits ripen. Two cDNA fragments, encoding two
divergent endo-beta-1,4-glucanases (faEG10 and faEG30, respectively), were
obtained by RT-PCR and the expression of their related mRNAs examined by n
orthern analysis. faEG30-related transcripts start to be detected in large
green fruits, while faEG10 expression is detected in white fruits. Thereaft
er, the amount of both EGase mRNAs increases throughout the ripening proces
s up to the stage of red ripe fruits. The fine structure of the cell wall w
eakening which occurs during the ripening is well in accordance with the ab
ove described biochemical and molecular data.