Figure 2.

MdMAPK3 promotes apple fruit softening during storage. A) Apple fruit transiently overexpressing MdMAPK3 (MdMAPK3-OE) or empty vector (control) during storage. MdMAPK3 was overexpressed in apple fruit using Agrobacterium-mediated injection. MdMAPK3-OE fruits were harvested 7 d after injection and stored at RT for 30 d. DAI, days after infiltration; DAS, days after storage. Scale bar, 2 cm. B) Immunoblot analysis of proteins from apple fruit injected with empty vector or MdMAPK3-Myc and detected using an anti-Myc antibody. Fruit tissue at the injection region was used for protein extraction. Tubulin was used as a loading control. C) Relative MdMAPK3 expression in the fruits shown in (A) by RT-qPCR analysis. D) Apple fruit firmness during storage. Fruits sampled at each sampling point were divided into 3 subgroups (5 fruits per subgroup) and each subgroup was considered 1 biological replicate. Three biological replicates were analyzed. Values are means ± Se. Statistical significance was determined using Student's t-test (**P < 0.01). n.s., no significant difference. E) Relative MdPG1 expression by RT-qPCR analysis. For RT-qPCR, 3 biological replicates were used as described in Fig. 1. Values represent means ± Se. Statistical significance was determined using Student's t-test (**P < 0.01). n.s., no significant difference.