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Title: MARKER PROTEINS ASSOCIATED WITH SOMATIC EMBRYOGENESIS OF WHEAT CALLUS CULTURES (REVISE TITLE AS PUBLISHED; ADD ACCEPT DATE)

Author
item FELLERS, JOHN - OKLAHOMA STATE UNIVERSITY
item GUENZI, ARRON - OKLAHOMA STATE UNIVERSITY
item Porter, David

Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/29/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: One of the major constraints in the development of a widely used genetic transformation system for developing new improved wheat cultivars has been the inability to use any (or all) elite wheat genetic backgrounds for targets to incorporate transgenes. Due to several biochemical and physiological mechanisms only a few wheat genotypes work well in the developing somatic embryos. This process is necessary to recover and regenerate genetically transformed plantlets. A better understanding of the process of somatic embryogenesis, and a way to identify genotypes that have a high potential of developing somatic embryos, is critical in order to optimize the transformation process. This study was undertaken to identify differences in two-dimensional protein electrophoresis patterns of embrogenic and non-embryogenic wheat callus. If a marker protein associated with embryogenesis was found, it would be useful in identifying other gentoypes with the capacity for somatic embryogenesis. We found two basic proteins with relative molecular weights of approximately 27 and 43 kilodaltons that were consistently associated with embryogenic callus. While more work is needed to understand how these proteins are involved in somatic embryogenesis, they appear to have the potential to serve as marker proteins for embryogenesis.

Technical Abstract: 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 in vivo labeled with 35-S-methionine and cysteine. Protein profile differences were examined in embryogenic (E-callus) and non-embryogenic (NE-callus) wheat callus 105 and 271 d after callus initiation growing on 5.6 and 9 uM 2,4-dichlorophenoxyacetic acid (2,4-D). Proteins unique to E-callus were identified by computer assisted analysis of scanned images of fluorographs in vivo labeled proteins of E- and NE-callus. Thirty-three embryogenic proteins (E-proteins) were identified in 105-d-old E-callus growing on 5.6 uM 2,4-D, 71 E-proteins in 105-d-old callus on 9 uM 2,4-D, 43 E-proteins in 271-d-old callus on 5.6 uM 2,4-D, and 39 E-proteins in callus 271-d-old callus growing on 9 uM 2,4-D. Of these E-proteins, 10 were in callus 105-d-old callus regardless of 2,4-D concentrations. Two E-proteins with relative molecular weights/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.