Woody plants and the application of molecular tools

Using various molecular biology tools three woody plant genera, Populus, Quercus, and Montanoa were chosen as experimental systems to elucidate heretofor unanswered questions.; To elucidate genetic mechanisms of control of vascular cambial differentiation, hybrid poplar clone 47-174 (Populus deltoides × trichocarpa) was used as a model to examine gene expression in wood forming tissue and as a result of wind stress or mechanical perturbation (MP). RNA isolated from stressed and non-stressed poplar stems was examined using differential display of PCR products. One hundred thirty differential display gel bands from stem tissue were cloned and sequenced. Northern analysis and BLAST searches confirmed that more than seventy of these clones represent expressed sequence tags (ESTs) for poplar genes expressed in wood forming tissue. An abundance of representation of stress related genes indicate the ESTs are from abiotic induced mechanical perturbation.; In the second study, DNA fingerprinting techniques were used for the identification of cultivars of Quercus × hispanica , the Lucombe oak. Using inter-simple sequence repeat (ISSRs) primers, 66 Q. × hispanica (and related) samples were analyzed and compared for band pattern differences to establish identities. DNA evidence revealed that some named cultivars had identical banding patterns, which then aided in identification of other named or unnamed cultivars with the same DNA banding patterns.; A phylogeny of the genus Montanoa based on the Internal Transcribed Spacer (ITS) and the External Transcribed Spacer (ETS) was created. The combined dataset supports the monophyly of the genus and an early evolutionary split that coincides with geographic distribution. One lineage is composed mostly of central and southern Mexican species whereas the other lineage contains those species endemic to Mesoamerica and South America. The relationships of Montanoa to other genera in the Heliantheae are briefly discussed.