The synergistic response of Arundo donax to multiple stressors: New insights from root genome-wide transcription analysis

Giant reed ( Arundo donax L.) has adapted itself to different adverse abiotic conditions such as water and nutrition stress, which is used as an emerging model to study response mechanism under varied stress conditions in plants. However, there is currently a lack of systematic comparative RNA-seq analysis of multiple stresses response mechanisms of giant reed. By analyzing publicly available transcriptome data, a total of 7475, 22,681 and 10,887 differentially expressed genes (DEGs) were identified in the roots of A. donax under drought, waterlogging and high nitrogen conditions, respectively. GO enrichment and KEGG pathway analysis showed that nitrogen metabolism and phenylpropanoid biosynthesis pathway were significant enriched under drought, waterlogging and high nitrogen stress conditions, whereas the gene expression patterns of these pathways were different under three stresses. Nitrogen content analysis showed that different stresses affect the accumulation and distribution of nitrogen across giant reed plants. In addition, pairwise comparison of DEGs under different stresses indicated that antioxidant defense systems and water balance maintenance play positive roles in multiple stressors response. Three stresses markedly increased the activities of the antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD), as well as glutathione (GSH) content to minimize oxidative damage. Transcriptomics and physiological analyses suggested that osmotic adjustment substance and aquaporins in plant roots positively contribute to modulating water homeostasis when exposed to external stimuli. Collectively, our findings revealed the gene regulatory networks of A. donax in response to multiple stressors and provided a novel understanding of the synergistic molecular mechanism of giant reed under different stress conditions. • Root transcriptomics revealed the response mechanism of A. donax under various stresses. • Regulation of nitrogen and phenylpropanoid metabolism helps adapt to various stresses. • Involvement of water balance and ROS scavenging is critical to resist multiple stressors. • Revealing gene networks responsive to stresses, offering candidate resistance genes.