Transcriptomics and metabolomics analysis reveal metabolic regulation of Populus davidiana × P. bolleana response to elevated CO₂

Populus davidiana × P. bolleana is an economically important tree species for the development of timber plantations, especially in Northern China. Populus davidiana × P. bolleana plays a role in forest production and environment. Nowadays, the effect of atmospheric carbon dioxide (CO₂)-caused climate change is an increasing concern and will affect plant secondary metabolism. In this study, transcriptomic and untargeted metabolome responses of Populus davidiana × P. bolleana to elevated concentrations of CO₂ were studied. Populus davidiana × P. bolleana were grown under three concentration of CO₂ (397 ppm, 550 ppm, 750 ppm) for 30 days. A total of 127,088,734 clean reads were obtained and assembled into 50498 unigenes (118087 transcripts); 50498 unigenes were annotated using different databases (NR, Swiss-Prot, KEGG, GO, eggNOG and Pfam). Additionally, 6416 differentially expressed genes (DEGs) were identified including 3202 up- and 3214 down-regulated genes. “Phenylpropanoid biosynthesis” and “flavonoid biosynthesis” enrich into the Kyoto encyclopedia of genes and genomes (KEGG) pathway. Moreover, 10460 and 9852 metabolites ions were identified using positive (pos) mode and negative (neg) mode, respectively. We conducted correlation analyses of enriched KEGG pathways of DEGs and accumulated metabolites, revealing that phenylpropanoid and flavonoid secondary metabolism pathways were enriched under CO₂ stress. The findings provide new insights of a molecular mechanism responsible for adaption of Populus davidiana × P. bolleana to CO₂ stress.

Investigated the effects of elevated CO₂ on Populus davidiana × P. bolleana using transcriptome and metabolome analysis. Results revealed changes in differentially expressed genes (DEGs) associated with phenylpropanoid and flavonoid biosynthesis pathways, suggesting an impact on the production of these metabolites.