Figure 8.

Expression of ACPK1 in different tissues and during fruit development. A, Expression of ACPK1 gene in different tissues. Total RNA (20 μg) from root (R), young stem (St), leaf (L), flesh (F), or seed (S) of berry, transferred on a nylon membrane after electrophoresed in an agarose gel, was probed with the ³²P-labeled cDNA fragment corresponding to the N-terminal variable domain of ACPK1 to detect specifically mRNA level of ACPK1 (ACPK1 mRNA). rRNA indicates the RNA samples stained with ethidium bromide. B, Expression of ACPK1 during berry development. Total RNA from berry tissues was probed as in A with the ³²P-labeled cDNA fragment corresponding to the N-terminal variable domain of ACPK1 to detect specifically mRNA level of ACPK1 (ACPK1 mRNA). rRNA, RNA samples stained with ethidium bromide. Total microsomal proteins (100 μg) extracted from berry tissues were immunoprecipitated with 5 μg anti-ACPK1-N⁴⁰ serum protein. The immunoprecipitated proteins were subjected to SDS-PAGE and then to the assays for detecting the levels of ACPK1 protein (ACPK1 protein, blotted with anti-ACPK1-N⁴⁰ serum), autophosphorylation (ACPK1 Autophosphorylation), or histone-phosphorylating kinase activity (ACPK1 Kinase activity) as described in “Materials and Methods.” The concentrations of ABA in the berry tissues (columnar figures, ABA content in berry) were determined by radioimmunoassay (values in the columnar figures are means of five replications ± se). I, II, III, and IV indicate the sampling dates that are the early stage of berry growth (10 d after anthesis, stage I), first rapid growth phase (stage II, 10th–30th d after anthesis), lag growth phase (stage III, 30th–50th d after anthesis), and second rapid growth phase or ripening stage (stage IV, 50th–80th d after anthesis).