The selection of plant genotypes characterized by wellness and stable growth under drought-stress conditions amid ongoing climate change is an important challenge in forest tree breeding. The introduction of molecular markers will enable efficient selection of breeding materials that are resistant to drought stress in forest trees as well as in crop species. Japanese cedar, Cryptomeria japonica, the most dominant forest species in Japan, grows well on mesic sites and is characterized by intraspecific variation in its drought-stress response. Here, we analyzed the physiological characteristics and gene expression profiles of multiple C. japonica genotypes under both control and drought-stress conditions to identify drought-responsive genes and develop gene expression markers that could assess the physiological status of cuttings based on their gene expression responses to dehydration. The two representative genes that showed a large expressional change in the later period after water withholding were both homologs of COR47, a gene to the dehydrin protein family, and of ERF016, a member of the dehydration-responsive element-binding (DREB) transcription factor family in Arabidopsis. We developed both intermediate- and small-scale sets of the gene-expression analysis platforms that allowed us to correlate gene expression with the physiological responses of cuttings to drought. The results highlight the potential to assess the environmental adaptability with gene expression analysis in C. japonica.
Keywords: desiccation; gene-expression markers; intraspecific variation; photosynthetic characteristics; sugi; transcriptome.
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