Trees of the genus Populus are the model tree species. The genome of Populus trichocarpa was completely sequenced and released into the public domain in the autumn of 2004. The Campbell lab is developing a burgeoning program in poplar genomics to address questions relating to carbon sequestration, wood formation, tree nutrition, tree health, and adaptation
to environmental factors, including climate change. The program builds on our experience with arabidopsis and, therefore, uses a comparative genomics approach to expand on our growing knowledge of the function of Populus genes. The results from our lab should have immediate application in efforts aimed at selection of superior poplar for carbon sequestration and
wood formation, and in understanding the genomic basis of adaptation. As such our work should find application in both tree improvement and forest conservation genetics.

In addition, recent work in the Campbell lab has also aimed to develop new tools to investigate gene function in poplar. A large amount of time is required for the rigorous assessment of the phenotypic effect of a gene and its implications in an ecological context. Recently, plant viruses have provided a useful and rapid means by which to analyse plant gene function. Virus-based genetic engineering systems take advantage of the natural
ability of viruses to express, replicate, and transmit their genetic material throughout the host plant. Insertion of foreign genes into the viral genome can be used to express a foreign gene throughout a plant. It might be possible to establish a similar system for trees, provided an
appropriate viral vector could be identified. The Campbell lab has been testing the possibility that poplar mosaic virus (PopMV) may be ideal in this regard. The group has sequenced the entire PopMV genome, and initiated studies aimed at understanding how PopMV propagates in the host, and how the host responds to the virus. The latter analyses have involved
microarray-based transcript profiling, and are amongst the first investigations of the response of the poplar transcriptome to any pathogen.

Personnel:

Dr. Christian Dubos

Patent filed:

Smith CM, Campbell MM (2003) Poplar mosaic virus: a gene function analysis
system for trees.

Publications (personnel supervised by Dr. Campbell are underlined):

Smith CM, Campbell MM (2004) Complete genome sequence of poplar mosaic
virus. Archives of Virology (in press) (BBSRC & CellFor funded)

Smith CM, Rodriguez-Buey M, Karlsson J, Campbell MM (2004) The response of
the poplar transcriptome to wounding and subsequent infection by a viral
pathogen. New Phytologist (in press) (BBSRC & CellFor funded)

Smith CM, Campbell MM (2004) Populus genotypes differ in infection and
systemic spread of Poplar mosaic virus (PopMV) Plant Pathology (in press)
(BBSRC & CellFor funded)