Transient expression of a pea MAP kinase gene induced by gibberellic acid and 6-benzyladenine in unpollinated pea ovaries

PsMAPK3, a new MAP kinase cDNA, was cloned from ovaries of Pisum sativum L. Expression of PsMAPK3 is at low basal levels in unpollinated ovaries but i t is rapidly induced by gibberellic acid (peak at 30 min) and 6-benzyladeni ne (peak at 45 min). Both treatments promoted the development of a partheno carpic fruit. In situ hybridization localized PsMAPK3 mRNA in ovules. The t ranscript was additionally detected in the mesocarp when it is expanding in response to the treatments. These observations suggest that gibberellins a nd cytokinins regulate PsMAPK3 mRNA levels in pea ovary shortly after fruit set is induced.