Submitted to: Molecular Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/16/2008
Publication Date: 7/8/2008
Citation: Petri, C., Webb, K.K., Hily, J., Dardick, C.D., Scorza, R. 2008. High transformation efficiency in plum (Prunus domestica L.): a new tool for functional genomics studies in Prunus spp. Molecular Breeding. DOI 10.1007/s11032-008-9200-8. Interpretive Summary: In order to study how genes control the growth and development of plants, "functional genomics" studies are used in which the genes of interest are repressed or otherwise altered in their expression, and are then transferred into model plants. While model plants, such as the small weed species Arabidopsis or tobacco, are useful for studying some plant genes, they are not useful for the study of some genes that are specific for trees. Transferring genes into trees for gene function studies has been hampered by the difficulty and inefficiency of the process in most trees. We have developed a gene transfer system for plum trees that is dependable, efficient, and fast. This will allow researchers to study important tree genes in the trees themselves. This can lead to breakthroughs in the genetic improvement of trees both through biotechnology and through traditional breeding methods.
Technical Abstract: An improved Agrobacterium-mediated transformation protocol in plum (Prunus domestica L.) cv 'Bluebyrd' using hypocotyl slices as source of explants is described. The addition of 2, 4-D to the regeneration media during co-culture allowed us to increase transformation efficiency up to 10 times over previous reports. Southern blot analysis of the putative transgenic shoots revealed transformation efficiencies up to 42% with an average of 25% over all trials. Timing in each step has been optimized producing self-rooted transgenic plants in approximately six months. In order to test the system, we developed a vector containing a hairpin Phytoene desaturase (PDS) gene fragment cloned from peach. This vector was used for targeted post-transcripcional gene silence (PTGS) providing an excellent collection of knockout PDS gene plants. This easy and efficient protocol may help to determine the roles of plant genes. Plum could become the model plant in Prunus spp. and even more so in Rosaceae where genes could be studied, and any hypotheses could be tested quickly and efficiently.