PDF(Pubmed)
Abstract：
Severe and frequent heat and drought events challenge the survival and development of long-generation trees. In this study, we investigated the genomic basis of heat tolerance, water use efficiency and growth by performing genome-wide association studies in coastal Douglas-fir (Pseudotsuga menziesii) and intervarietal (menziesii × glauca) hybrid seedlings. GWAS results identified 32 candidate genes involved in primary and secondary metabolism, abiotic stress and signaling, among other functions. Water use efficiency (inferred from carbon isotope discrimination), photosynthetic capacity (inferred from %N), height and heat tolerance (inferred from electrolyte leakage in a heat stress experiment) were significantly different among Douglas-fir families and varieties. High-elevation seed sources had increased water use efficiency, which could be a result of higher photosynthetic capacity. Similarly, families with greater heat tolerance also had higher water use efficiency and slower growth, suggesting a conservative growth strategy. Intervarietal hybrids showed increased heat tolerance (lower electrolyte leakage at 50 and 55 °C) and higher water use efficiency compared with coastal families, suggesting that hybridization might be a source of pre-adapted alleles to warming climates and should be considered for large-scale reforestation projects under increasingly arid conditions.
摘要：
严重和频繁的高温和干旱事件挑战了长代树木的生存和发展。在这项研究中,我们研究了耐热性的基因组基础，通过在沿海道格拉斯冷杉（Pseudotsugamenziesii）和品种间（menziesii×glauca）杂交幼苗中进行全基因组关联研究，提高水分利用效率和生长。GWAS结果确定了涉及初级和次级代谢的32个候选基因，非生物胁迫和信号，在其他功能中。水利用效率(从碳同位素判别推断)，光合能力(从%N推断)，道格拉斯冷杉家族和品种之间的高度和耐热性（根据热应力实验中的电解质泄漏推断）显着不同。高海拔种子源提高了水分利用效率，这可能是光合能力较高的结果。同样，耐热性较高的家庭也有较高的水分利用效率和较慢的增长，建议采取保守的增长策略。与沿海家庭相比，品种间杂种表现出更高的耐热性（在50和55°C时电解质泄漏较低）和更高的水利用效率，这表明杂交可能是气候变暖的预先适应等位基因的来源，应该考虑在日益干旱的条件下进行大规模的植树造林项目。
