Examination of the Transcriptional Response to Overexpression in (Lamb.) Carr.

The study of somatic embryogenesis can provide insight into early plant development. We previously obtained -overexpressing embryonic cell lines of (Lamb.) Carr. To further elucidate the molecular mechanisms associated with in this species, the transcriptional profiles of wild-type (WT) and three -overexpressing transgenic cell lines were subjected to RNA sequencing using the Illumina NovaSeq 6000 system. In total, 203,256 unigenes were generated using Trinity de novo assembly, and 2467 differentially expressed genes were obtained by comparing transgenic and WT lines. In addition, we analyzed the cleaved degree of target genes in different transgenic cell lines by detecting the expression pattern of , and their cleaved degree in transgenic cell lines was higher than that in WT. The downstream genes of were identified using Pearson correlation coefficients. Yeast one-hybrid and dual-luciferase report assays revealed that the transcription factors LaHDZ31-34 could bind to the promoters of , , , and . This is the first report of gene expression changes caused by overexpression in Japanese larch. These findings lay a foundation for future studies on the regulatory mechanism of miR166.