Lai Zhao, Gross Briana L, Zou Yi, Andrews Justen, Rieseberg Loren H
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Mol Ecol. 2006 Apr;15(5):1213-27. doi: 10.1111/j.1365-294X.2006.02775.x.
This paper describes the creation of a cDNA microarray for annual sunflowers and its use to elucidate patterns of gene expression in Helianthus annuus, Helianthus petiolaris, and the homoploid hybrid species Helianthus deserticola. The array comprises 3743 ESTs (expressed sequence tags) representing approximately 2897 unique genes. It has an average clone/EST identity rate of 91%, is applicable across species boundaries within the annual sunflowers, and shows patterns of gene expression that are highly reproducible according to real-time RT-PCR (reverse transcription-polymerase chain reaction) results. Overall, 12.8% of genes on the array showed statistically significant differential expression across the three species. Helianthus deserticola displayed transgressive, or extreme, expression for 58 genes, with roughly equal numbers exhibiting up- or down-regulation relative to both parental species. Transport-related proteins were strongly over-represented among the transgressively expressed genes, which makes functional sense given the extreme desert floor habitat of H. deserticola. The potential adaptive value of differential gene expression was evaluated for five genes in two populations of early generation (BC2) hybrids between the parental species grown in the H. deserticola habitat. One gene (a G protein-coupled receptor) had a significant association with fitness and maps close to a QTL controlling traits that may be adaptive in the desert habitat.
本文描述了一年生向日葵cDNA微阵列的构建及其在阐明向日葵、叶柄向日葵和同倍体杂交种沙漠向日葵基因表达模式中的应用。该阵列包含3743个EST（表达序列标签），代表约2897个独特基因。其平均克隆/EST一致性率为91%，适用于一年生向日葵的种间研究，并且根据实时RT-PCR（逆转录-聚合酶链反应）结果显示出高度可重复的基因表达模式。总体而言，阵列上12.8%的基因在这三个物种间表现出统计学上显著的差异表达。沙漠向日葵有58个基因表现出超亲或极端表达，相对于两个亲本物种，上调和下调的基因数量大致相等。在超亲表达的基因中，与运输相关的蛋白质大量富集，鉴于沙漠向日葵极端的沙漠底部栖息地，这在功能上是合理的。对生长在沙漠向日葵栖息地的亲本物种间早期世代（BC2）杂交种的两个群体中的五个基因，评估了差异基因表达的潜在适应性价值。一个基因（一种G蛋白偶联受体）与适合度显著相关，并且定位在一个控制可能适应沙漠栖息地性状的QTL附近。
