Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan.
PLoS One. 2020 Jan 28;15(1):e0228278. doi: 10.1371/journal.pone.0228278. eCollection 2020.
Long-lived forest tree species experience a wide range of environmental conditions throughout their lifespan. Evaluation of the underlying growth and development mechanisms of these species is essential to predict tree growth under climate change. This study investigated climate sensitivity to temperature, precipitation, dry periods, and the associated genomic regions in Cryptomeria japonica, Japan's most commercially important tree. We used tree rings and common garden experiments with three clonal replicates planted in two contrasting environments in Kyushu (Kumamoto site) and Honshu (Chiba site), Japan. Tree growth showed a significant negative correlation with the dry period (>4 days) in March of the year of tree-ring formation at the Chiba site. In contrast, temperature and precipitation had little influence on tree growth. Quantitative trait locus (QTL) analysis was performed to investigate climate sensitivity to dry periods at the Chiba site, revealing 13 significant QTLs. One QTL showed a substantially large contribution to the overall climate sensitivity, accounting for 12.4% of the total phenotypic variation. The phenotypic variance explained (PVE) by other QTLs ranged from 0.9% to 2.9%, and the total PVE by all QTLs was 35.6%. These findings indicate that the tree population at the Chiba site could be vulnerable to drought in early spring and that the QTL showing the greatest impact on climate sensitivity may be closely related to genes associated with tolerance or adaptation to drought stress. The QTLs identified in this study could be useful for molecular breeding, forest management, and predicting the growth of C. japonica under a changing climate.
长寿的森林树种在其整个生命周期中经历了广泛的环境条件。评估这些树种潜在的生长和发育机制对于预测气候变化下的树木生长至关重要。本研究调查了日本最具商业价值的树种之一日本柳杉对温度、降水、干旱期的气候敏感性及其相关的基因组区域。我们使用树木年轮和三个克隆重复种植在日本九州（熊本地点）和本州（千叶地点）两个对比环境中的共同花园实验。树木生长与千叶地点树木年轮形成当年 3 月的干旱期（>4 天）呈显著负相关。相比之下，温度和降水对树木生长的影响较小。进行了数量性状位点（QTL）分析，以研究千叶地点对干旱期的气候敏感性，发现了 13 个显著的 QTL。一个 QTL 对整体气候敏感性有很大的贡献，占总表型变异的 12.4%。其他 QTL 的表型方差解释（PVE）范围为 0.9%至 2.9%，所有 QTL 的总 PVE 为 35.6%。这些发现表明，千叶地点的树木种群可能容易受到早春干旱的影响，对气候敏感性影响最大的 QTL 可能与与耐旱性或适应干旱胁迫相关的基因密切相关。本研究中鉴定的 QTL 可用于分子育种、森林管理和预测气候变化下日本柳杉的生长。
