Abstract

Big sagebrush (Artemisia tridentata) is one of the ecologically most important shrub species in western North America. The species serves as a major source of food and habitat for the near-threatened sage grouse and various other fauna. Habitat loss due to a combination of disturbances followed by establishment of invasive plant species is considered as a serious threat to sustainability of the big sagebrush ecosystem. Because of its importance, restoration of this species is very crucial to those dependent on big sagebrush community. However, restoration of big sagebrush carried out by using diverse seed source can lead to imbalance and degradation in the native ecosystem. Therefore, restoration works aided by understanding of adaptive traits of big sagebrush using molecular markers will aid successful restoration. The major objective of this research was to create a substantial resource of nuclear sequence data and identify markers that can be used in future studies in big sagebrush. We report the development and annotation of the first expressed sequence tag (EST) collection for big sagebrush based on 454 sequencing of leaf tissue. Expressed genes of subspecies tridentata and vaseyana were sequenced using the 454 GS-FLX titanium platform, which produced 823,392 reads with an average read length of 404 bp and 702,001 reads with an average read length of 333 bp for sspp. tridentata and vaseyana, respectively. Assembly of the reads resulted in 212,102 consensus sequences in ssp. tridentata and 199,439 in ssp. vaseyana. A combined assembly of both subspecies sequences generated 29,541 contigs with an average length of 796 bp and 275,866 singletons with an average length of 370 bp. A BLASTx search against the non-redundant (NR) protein database using the contigs obtained from a combined assembly resulted in 21,436 sequences with significant blast alignments (≤ 1e-15). Gene Ontology (GO) IDs were assigned to 18,397 sequences. A total of 20,952 SNPs were detected between the two subspecies and 1,182 SNPs were confirmed in tetraploid ssp. wyomingensis. In addition, 1,003 and 507 SSRs were detected in ssp. tridentata contigs and ssp. vaseyana contigs, respectively.

Degree

MS

College and Department

Life Sciences; Plant and Wildlife Sciences

Rights

http://lib.byu.edu/about/copyright/

Date Submitted

2011-06-22

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd4507

Keywords

Artemisia tridentata, EST assembly, 454 sequencing, SNPs, SSRs, Ka, Ks

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