Yang Suk-Hwan, Loopstra Carol A
Institute for Plant Genomics and Biotechnology and The Department of Forest Science, Molecular and Environmental Plant Science, Texas A&M University, College Station, TX 77843-2123, USA.
Tree Physiol. 2005 Aug;25(8):1063-73. doi: 10.1093/treephys/25.8.1063.
In developing xylem, gene expression levels vary in different genotypes, at different stages of development, throughout a growing season, and in response to stresses. Commercially important characteristics such as wood-specific gravity are known to differ with seed source. For example, when grown on a common site, the specific gravity of Arkansas loblolly pine (Pinus taeda L.) trees is greater than that of Louisiana loblolly pine, and Texas loblolly pines have a greater specific gravity than loblolly pines from the Atlantic coast. A microarray analysis was performed to examine variation in gene expression among trees from different geographical sources when grown on a common site, and seasonal variation in gene expression in each seed source. We used microarrays containing 2171 expressed sequence tags (ESTs) with putative functions of interest, selected from several loblolly pine xylem partial cDNA libraries and a shoot tip library. Genes with significant variation in expression for each factor were identified. Many genes preferentially expressed in latewood compared with earlywood were for proteins involved in cell wall biosynthesis. Variation in gene expression among trees from the two seed sources in each growing season suggests that there may be more differences between South Arkansas trees and South Louisiana trees in latewood than in earlywood. Variation in gene expression among trees from different regions may reflect adaptation to different environments.
在发育中的木质部中，基因表达水平在不同基因型、不同发育阶段、整个生长季节以及对胁迫的响应中都会有所变化。已知诸如木材比重等具有商业重要性的特征会因种子来源不同而有所差异。例如，当种植在同一地点时，阿肯色州火炬松（Pinus taeda L.）树木的比重高于路易斯安那州火炬松，而得克萨斯州火炬松的比重比来自大西洋沿岸的火炬松更大。进行了一项微阵列分析，以研究在同一地点生长的不同地理来源树木之间基因表达的差异，以及每个种子来源中基因表达的季节性变化。我们使用了包含2171个具有假定感兴趣功能的表达序列标签（EST）的微阵列，这些标签选自几个火炬松木质部部分cDNA文库和一个茎尖文库。确定了每个因素在表达上有显著差异的基因。与早材相比，许多在晚材中优先表达的基因是参与细胞壁生物合成的蛋白质。每个生长季节中两个种子来源树木之间基因表达的差异表明，阿肯色州南部树木和路易斯安那州南部树木在晚材中的差异可能比在早材中更多。不同地区树木之间基因表达的差异可能反映了对不同环境的适应性。
