Marker proteins associated with somatic embryogenesis of wheat callus cultures

Abstract

Summary A marker protein for embryogenic potential could be useful in determining if target tissue for microprojectile bombardment has the ability to regenerate plants. The identification of such a protein in wheat callus cultures was approached by using isoelectric focusing and SDS-PAGE of proteins labeled in vivo with 35[S]-methionine and cysteine. Protein profile differences were examined in embryogenic (E-callus) and non-embryogenic (NE-callus) wheat callus, 105 or 271 d after callus initiation. Callus was maintained on medium containing either 5.6 or 9 μmol/L 2,4-dichlorophenoxyacetic acid (2,4-D). Proteins unique to E-callus (E-proteins) were identified by computer assisted analysis of scanned images of fluorographs of in vivo-labeled proteins of E- and NE-callus. Thirty-three E-proteins were identified in 105-day-old E-callus growing on 5.6 μmol/L 2,4-D, 71 E-proteins in 105-day-old callus on 9 μmol/L 2,4-D, 43 E-proteins in 271-day-old callus on 5.6 μmol/L 2,4-D, and 39 E-proteins in 271-day-old callus growing on 9 μmol/L 2,4-D. Of these E-proteins, 10 were in 105-day-old callus regardless of 2,4-D concentration. One E-protein was present in 271-day-old callus from both 2,4-D concentrations. Two E-proteins with relative molecular masses/pis of 43.0/7.6 and 27.0/8.2 were present in E-callus from three of the four treatments. These proteins could be used as markers for determining if tissue has embryogenic potential.