Highlights 1997-1998

• Monsanto Company joins TGERC as the 14th Regular Member.

 

• TGERC staff obtained new grants to accelerate work on genes to control flowering. With grants from the Consortium for Plant Biotechnology and Monsanto we will be exploring new genes that control readiness to flower in trees, and testing dominant negative mutant genes in Arabidopsis to guide our ongoing work in poplars. These studies may provide new approaches for advancing and delaying flowering in trees, which can increase the efficiency of research and breeding, and simplify use of transgenic trees.

 

• The promoter from the poplar PTD gene shows floral-specific expression in Arabidopsis and may contain a strong matrix attachment region (MAR). Floral expressionindicates that PTD promoter is likely to be useful for controlling gene expression both in poplars and in other species, and thus may be important for inducing sterility. Engineered sterility would facilitate ecological analysis and regulatory approval of transgenic plantations. The promoter also has multiple DNA sequence motifs that closely resemble those in strong MARs, which increase and stabilize transgene expression.

 

• A field trial was established to screen transgenic lines of commercial hybrid cottonwoods for superior glyphosate tolerance. A total of 73 lines are being tested with high levels of Roundup on Potlatch's research site in eastern Oregon. Elite lines will be propagated for large-scale trials to study the value and ecological impact of glyphosate-tolerant plantations.

 

• Two field trials were installed to study resistance to leaf beetles in transgenic commercial clones of hybrid cottonwoods. A total of 53 lines are being tested on Boise Cascade land in southeastern Washington and on Fort James land in northwestern Oregon. Most of the lines showed high resistance to the cottonwood leaf beetle in greenhouse trials. We will evaluate the degree of resistance imparted by various levels of expression of the inserted genes, the effects of defoliation on tree growth, and the impact of the gene transfer process on growth and form.

 

• \r\n\r\nNine highly plymorphic DNA markers were developed that are suitable for paternity analyses and DNA fingerprinting of poplars. Working with the Poplar Molecular Genetics Cooperative we identified a set of simple sequence repeat (SSR) DNA markers that were reliable in the laboratory and showed very high levels of genetic polymorphism in black cottonwood. These will be used to study movement of pollen and seeds from plantations and wild stands, generating information for assessing the risks of gene escape from transgenic plantations.

 

• Seven Members supported OSU in filing U.S. and Canadian patent applications for the DNA sequences of four floral homeotic genes. The genes are two poplar homologs of AGAMOUS, and one each of LEAFY and APETALA3 from Arabidopsis. The sequences of one or more of these genes, or their regulatory regions, should be useful for genetic engineering of sterility in poplar and other tree species.