Since strawberry is a non-climacteric fruit, auxins could regulate
their ripening events being the achenes the endogenous source
of auxins (Given et al., 1988). As shown in Fig. 3A and B the expression
of FaEXP1 and FaEXP2 was affected by auxin. The removal of
achenes from LG fruit induced a rapid increase in mRNA accumulation
of FaEXP1 and FaEXP2 genes (see −/− treatment). On the other
hand, de-achened fruit treated with NAA (−/+ treatment) showed
a reduction in the level of FaEXP1 and FaEXP2 transcript accumulation
compared to de-achened fruit. In addition, the application
of NAA to intact fruit (+/+ treatment) reduced transcript accumulation
of FaEXP1 and FaEXP2 compared to non-treated fruit (+/−
treatment). These results indicate a clear repression of expression
of FaEXP1 and FaEXP2 genes by auxins. The expression of FaEXP5
gene in de-achened fruit was also induced compared to intact
fruit, however the effect was less intense than with FaEXP1 and
FaEXP2 (Fig. 3D). Moreover, the application of NAA to de-achened
fruit (−/+) was not able to repress the expression of FaEXP5 compared
to de-achened fruit. This indicates that the expression of
FaEXP5 gene was also regulated by auxins but the application of
exogenous auxin did not reduce the gene expression level of this
expansin