Transcriptional analyses reveal the molecular mechanism governing shade tolerance in the invasive plantSolidago canadensis

Solidago canadensisis an invasive plant that is capable of adapting to variable light conditions. To elucidate the shade tolerance mechanism inS. canadensisat the molecular level, transcriptome analyses were performed for leaves growing under natural light and three shade level conditions. Many differentially expressed genes (DEGs) were found in the comparative analysis, including those involved in photosynthesis, antioxidant, and secondary metabolism of phenol- and flavonoid-related pathways. Most genes encoding proteins involved in photosynthesis, such as photosystem I reaction center subunit (Psa), photosystem II core complex protein (Psb), and light-harvesting chlorophyll protein (Lhca and Lhcb), and reactive oxygen species (ROS) scavenging-related enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were upregulated with the shade levels. Furthermore, most of the DEGs related to secondary metabolite synthesis were also upregulated in the shade conditions. Our study indicates thatS.canadensiscan respond to shade stress by modulating the expression of several photosynthesis-related, free radical scavenging-related, and secondary metabolism-related genes; thus, this species has the ability to adapt to different light conditions.