John CairneyAssociate Professor School of Biology Ph.D., University of Dundee, Scotland,    1986

John Cairney obtained his education in Scotland, gaining his B.S. (Honours) in Molecular Biology in 1982 at the University of Glasgow and his Ph.D. in the Department of Biochemistry (now School of Life Sciences) at the University of Dundee in 1986. He was awarded a European Molecular Biology Organization Fellowship to conduct postdoctoral research at the Max Planck Institute for Molecular Genetics in Berlin, Germany, and after further postdoctoral research at Columbia University, NY, and Texas A&M University, he became a faculty member at Texas A&M in the Department of Forest Science. Dr. Cairney joined IPST as an Assistant Professor in 1994. Dr. Cairney's research interests are in gene regulation during embryo development in loblolly pine. This work focuses upon both natural development within pine seeds and in a laboratory setting, during somatic embryogenesis. In complementary projects, the control of gene expression under drought conditions is being studied.

Research Summary

Gene Expression During Pine Embryogenesis

Embryogenesis, in plants as in animals, is an exquisitely controlled sequence of events, wherein subtle biochemical alterations mediate major changes in form and function. Perhaps, surprisingly, the process of embryo formation in the seed can be mimicked in the laboratory in a technique called Somatic Embryogenesis.

Figure 1
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This method permits the multiplication of embryos that are subsequently matured and germinated into pine plantlets. The process begins by extracting seeds from pine cones and cracking them open to reveal the ovule. Ovules, which contain immature embryos are then excised from seeds and are placed on an Intitation medium. An amorphous tissue containing embryo-like structures, an embryogenic mass, is extruded from the ovule. The embryogenic mass is transferred into liquid Multiplication media which permits embryos to multiply rapidly, though their development is limited. Transfer to a second, semi-solid gelled Maturation medium of different composition encourages the embryos to continue development. Finally embryos are germinated and the resulting plantlets are transferred into soil and into the greenhouse from where they may be planted as normal seedlings.

The process is rapid and thousands of embryos can be produced in a flask, matured, and converted into plantlets. Thus, somatic embryogenesis has the potential to provide thousands of high-quality embryos of the best trees available. Current concerns over the North American fiber supply make this a very important avenue of research.

Somatic embryogenesis, however, is a rather inefficient process and the quality of embryos and plantlets can be poor. It is very dependent on genotype and species. Improving the process requires an understanding of the process of embryogenesis in the natural state.

The principal agents of biochemical change are the genes that encode proteins whose action is needed at different times in development; thus, gene activity is carefully regulated. How natural (zygotic) and laboratory (somatic) embryos differ in terms of gene activity is unknown. My research group has recently developed techniques for applying a molecular technique called Differential Display to the study of pine embryo gene expression (Xu, et al. 1997, 2001). We have been able to follow the activity of hundreds of pine genes during development, generating results with as little starting material as a single embryo (Cairney, et al. 1997, 1999, 2000). Several hundred cDNAs have been cloned, sequenced, and compared to GenBank files. Similarities to many well-characterized genes have been noted. In this way, we will be able to follow the activity of specific genes and construct testable hypotheses about the biochemical events occurring during embryogenesis. Complementary work studies the regulation of specific genes in greater detail (Ciavatta et al 2001). From these experiments, and experiments arising from them, we will be able to design better culturing protocols, better cultivation conditions, and thereby improve somatic embryogenesis.