Transcript profiling and genome mapping in black spruce (Picea mariana).
Date
2007
Authors
Mann, Ishminder K.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
Conifers represent an ecologically and economically important group of extant gymnosperms. They are primarily distributed in forests of the Northern-Hemisphere, supplying timber, pulp and resin resources. Picea (spruce) and Pinus (pine) are the two major genera in the family Pinaceae of conifers. Spruce genomics research is challenging because of the large genome size, the abundance of highly repetitive elements in its genome, paucity of sequence data and lack of advanced generation pedigrees. The results reported are a part of an active research program on structural and functional genomics of black spruce (Picea mariana), red spruce (Picea rubens) and their hybrids related to growth and adaptation to climate change being conducted under the leadership of my supervisor Dr. Om Rajora. The research objectives were to (1) develop an expressed sequence tag (EST) resource, (2) identify differentially-expressed genes in needle versus cambium tissues, and (3) construct a high density genetic linkage map, which could be used in mapping of traits related to growth and adaptation in black spruce.
An EST resource has been generated in black spruce by partially sequencing cDNA clones from a standard cDNA library developed from needles. Approximately 13% of the ESTs from black spruce showed no identity with sequences in the available EST database at the National Centre for Biotechnology Information (NCBI). A total of 586 transcripts coding for proteins with known functions have been annotated. The ESTs generated were compared with the EST databases from representative species belonging to conifers, monocots and eudicots to determine the extent of EST similarities. The ESTs from black spruce showed higher sequence similarities with conifers followed by eudicots than with monocots.
Transcriptome profiling of needle and cambium tissues was conducted. Differentially-expressed transcripts were identified in needle versus cambium tissues of black spruce via analysis of ESTs and dot-blot hybridization of cDNA clones from subtracted cDNA libraries. Transcripts coding for proteins involved in disease and stress response mechanisms, and cell structure were predominantly expressed in the cambium tissues, whereas those involved in photosynthesis, energy and metabolism were predominantly expressed in the needle tissues.
A near-saturated genetic linkage map of black spruce was developed using a three-generation outbred pedigree and amplified fragment length polymorphism (AFLP), selectively amplified microsatellite polymorphic loci (SAMPL), expressed sequence tag polymorphism (ESTP) and microsatellite (mostly cDNA based) markers. The consensus map had 941 markers distributed over 12 linkage groups, and covered more than 96% of black spruce genome. The mapped markers included 695 AFLPs, 213 SAMPL, 30 microsatellites and 3 ESTPs. Total estimated map length was 1898 cM, with an average of one marker every 2 cM. This is the first genetic linkage map of Picea mariana, and the first of its kind in the genus Picea based on a three-generation outbred pedigree.
Thesis (Ph.D.)--Dalhousie University (Canada), 2007.
An EST resource has been generated in black spruce by partially sequencing cDNA clones from a standard cDNA library developed from needles. Approximately 13% of the ESTs from black spruce showed no identity with sequences in the available EST database at the National Centre for Biotechnology Information (NCBI). A total of 586 transcripts coding for proteins with known functions have been annotated. The ESTs generated were compared with the EST databases from representative species belonging to conifers, monocots and eudicots to determine the extent of EST similarities. The ESTs from black spruce showed higher sequence similarities with conifers followed by eudicots than with monocots.
Transcriptome profiling of needle and cambium tissues was conducted. Differentially-expressed transcripts were identified in needle versus cambium tissues of black spruce via analysis of ESTs and dot-blot hybridization of cDNA clones from subtracted cDNA libraries. Transcripts coding for proteins involved in disease and stress response mechanisms, and cell structure were predominantly expressed in the cambium tissues, whereas those involved in photosynthesis, energy and metabolism were predominantly expressed in the needle tissues.
A near-saturated genetic linkage map of black spruce was developed using a three-generation outbred pedigree and amplified fragment length polymorphism (AFLP), selectively amplified microsatellite polymorphic loci (SAMPL), expressed sequence tag polymorphism (ESTP) and microsatellite (mostly cDNA based) markers. The consensus map had 941 markers distributed over 12 linkage groups, and covered more than 96% of black spruce genome. The mapped markers included 695 AFLPs, 213 SAMPL, 30 microsatellites and 3 ESTPs. Total estimated map length was 1898 cM, with an average of one marker every 2 cM. This is the first genetic linkage map of Picea mariana, and the first of its kind in the genus Picea based on a three-generation outbred pedigree.
Thesis (Ph.D.)--Dalhousie University (Canada), 2007.
Keywords
Biology, Bioinformatics.