Figure 6.

Involvement of ethylene in the response of citrus fruits to elicitor treatment and to Penicillium digitatum infection. (a) Northern blot analysis of CsACO in the flavedo and albedo of oranges: NT, nontreated; I, infected; IC, infected and cured; X, nonwounded; C, cured; WC, wounded and cured. (b) CsACO mRNA accumulation in oranges infected with P. digitatum during 1, 2 and 3 days. Fruits were nontreated (NT), wounded and water inoculated (W) or wounded and inoculated with a suspension of 10⁶ conidia/mL of P. digitatum (I). In (a) and (b), relative accumulation (R.A.) values of CsACO mRNA in arbitrary units are shown at the bottom. Normalization was carried out with respect to the hybridization signal of the Citrus sinensis 26S rRNA using the flavedo infected with P. digitatum for 1 day (I1) as a reference. Hybridization with the P. digitatum 28S rDNA probe is shown at the bottom. (c) Ethylene production in discs of nontreated oranges (●), infected fruits (), cured fruits (), wounded and cured fruits (□) and infected and cured fruits (◊). Values represent the average of three replicates, including 10 discs in each replicate, ± SD.