The lipid-transfer protein C of Ricinus communis L.: isolation of two cDNA sequences which are strongly and exclusively expressed in cotyledons after germination.

Differential screening of cDNA libraries from Ricinus communis L. cotyledons at the day 4 of germination against those at day 2 led to the isolation of two cDNA sequences which code for type C of the "nonspecific lipid-transfer protein". The two clones are nearly identical in the coding region, which in each case starts with a sequence coding for a signal peptide. In the non-coding regions there is only 40% identity. Both clones are expressed only in the cotyledons and are strongly developmentally regulated, being exclusively expressed after the second day of germination with a maximum at days 4 and 5. No transcripts were found in the hypocotyls, roots or endosperm of seedlings and none in sink and source leaves of mature Ricinus plants.