@article{stasolla_bozhkov_chu_van zyl_egertsdotter_suarez_craig_wolfinger_von arnold_sederoff_2004, title={Variation an transcript abundance during somatic embryogenesis in gymnosperms}, volume={24}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/24.10.1073}, abstractNote={Somatic embryogenesis of Norway spruce (Picea abies L.) is a versatile model system to study molecular mechanisms regulating embryo development because it proceeds through defined developmental stages corresponding to specific culture treatments. Normal embryonic development involves early differentiation of proembryogenic masses (PEMs) into somatic embryos, followed by early and late embryogeny leading to the formation of mature cotyledonary embryos. In some cell lines there is a developmental arrest at the PEM-somatic embryo transition. To learn more about the molecular mechanisms regulating embryogenesis, we compared the transcript profiles of two normal lines and one developmentally arrested line. Ribonucleic acid, extracted from these cell lines at successive developmental stages, was analyzed on DNA microarrays containing 2178 expressed sequence tags (ESTs) (corresponding to 2110 unique cDNAs) from loblolly pine (Pinus taeda L.). Hybridization between spruce and pine species on microarrays has been shown to be effective (van Zyl et al. 2002, Stasolla et al. 2003). In contrast to the developmentally arrested line, the early phases of normal embryo development are characterized by a precise pattern of gene expression, i.e., repression followed by induction. Comparison of transcript levels between successive stages of embryogenesis allowed us to identify several genes that showed unique expression responses during normal development. Several of these genes encode proteins involved in detoxification processes, methionine synthesis and utilization, and carbohydrate metabolism. The potential role of these genes in embryo development is discussed.}, number={10}, journal={TREE PHYSIOLOGY}, author={Stasolla, C and Bozhkov, PV and Chu, TM and Van Zyl, L and Egertsdotter, U and Suarez, MF and Craig, D and Wolfinger, RD and Von Arnold, S and Sederoff, RR}, year={2004}, month={Oct}, pages={1073–1085} }
 @article{stasolla_scott_egertsdotter_kadla_d o'malley_sederoff_zyl_2003, title={Analysis of lignin produced by cinnamyl alcohol dehydrogenase-deficient Pinus taeda cultured cells}, volume={41}, ISSN={["0981-9428"]}, DOI={10.1016/S0981-9428(03)00051-2}, abstractNote={Comparative studies were conducted on composition of lignin produced both in vivo and in vitro by cinnamyl alcohol dehydrogenase (CAD)-deficient mutant loblolly pine (Pinus taeda L.). In vivo studies were performed using differentiating xylem obtained from two genotypes of heterozygous (CAD/cad) and two genotypes of homozygous (cad/cad) CAD-deficient mutant trees. In vitro studies were performed using a culture system in which cells, generated from the same genotypes, were induced to produce lignin in culture. Steady state RNA levels and enzyme activity of CAD were dramatically reduced in both xylem and cultured cells obtained from homozygous mutant trees, compared to their heterozygous counterparts. Light microscopic studies showed pronounced differences during the lignin formation between homozygous and heterozygous cells. Phenolic compounds in the heterozygous (CAD/cad) cells were deposited around the cell wall, accumulated preferentially in vacuoles of the homozygous (cad/cad) cells. Differences in lignin composition as revealed by thioacidolysis were also observed. Lignin of both xylem tissue and cultured cells obtained from CAD-deficient homozygotes showed lower levels of coniferyl alcohols and significant enrichments in dihydroconiferyl alcohol (DHCA) and coniferyl aldehyde, compared to their heterozygous counterparts. The striking similarities in lignin composition observed both in vivo and in vitro, open new possibilities for the use of culture systems aimed at revealing the mechanisms controlling lignin biosynthesis, and the formation of DHCA subunits.}, number={5}, journal={PLANT PHYSIOLOGY AND BIOCHEMISTRY}, author={Stasolla, C and Scott, J and Egertsdotter, U and Kadla, J and D O'Malley and Sederoff, R and Zyl, L}, year={2003}, month={May}, pages={439–445} }
 @article{stasolla_zyl_egertsdotter_craig_liu_sederoff_2003, title={The effects of polyethylene glycol on gene expression of developing white spruce somatic embryos}, volume={131}, ISSN={["1532-2548"]}, DOI={10.1104/pp.015214}, abstractNote={Abstract}, number={1}, journal={PLANT PHYSIOLOGY}, author={Stasolla, C and Zyl, L and Egertsdotter, U and Craig, D and Liu, WB and Sederoff, RR}, year={2003}, month={Jan}, pages={49–60} }
 @article{stasolla_zyl_egertsdotter_craig_liu_sederoff_2003, title={Transcript profiles of stress-related genes in developing white spruce (Picea glauca) somatic embryos cultured with polyethylene glycol}, volume={165}, ISSN={["0168-9452"]}, DOI={10.1016/S0168-9452(03)00228-0}, abstractNote={The effect of polyethylene glycol (PEG) on the transcript level of 512 stress-related genes was analyzed by cDNA microarray. Major changes in gene expression between control and PEG-treated embryos were observed during the initial stages of development, upon transfer of the embryogenic tissue on maturation medium, and during the late phases of development, culminating with the generation of cotyledonary embryos. Only small changes in gene expression were observed during the intermediate phases of embryo development. The transcript levels of several genes involved in cell aging and detoxification mechanisms, including peroxidases and chitinases, were developmentally regulated during the embryogenic process. Major differences in the expression of these genes were observed between control and PEG-treated embryos. Based on their expression profiles, four different clusters of genes involved in stress response mechanisms were identified. The first group of genes, which included several heat shock proteins, was up-regulated in PEG-treated immature embryos. An opposite tendency was observed for a second cluster of genes, which included a glutathione-S-transferase, and a cysteine protease. The third class included genes repressed by PEG in fully developed embryos, whereas a fourth group of genes, which included several heat shock proteins and ubiquitin, was induced in PEG-treated embryos at the end of the culture period. Difference in transcript levels and profiles of several genes involved in cell wall and lignin biosynthesis were also observed between control and PEG-treated embryos.}, number={4}, journal={PLANT SCIENCE}, author={Stasolla, C and Zyl, L and Egertsdotter, U and Craig, D and Liu, WB and Sederoff, RR}, year={2003}, month={Oct}, pages={719–729} }