Transcriptome profiling of Arabidopsis thaliana roots in response to allelopathic effects of Conyza canadensis

The molecular mechanisms underlying allelopathy and their role in the interactions between invasive weeds and native species remain unclear. In this study, we aimed to explore the physiological and molecular response of plant roots of a native species to allelopathy from an invasive weed. We examined the growth and development of roots of native Arabidopsis thaliana for a 2-week period after being treated with aqueous extracts at different concentrations from invasive Conyza canadensis. Extracts with higher concentration in the Murashige and Skoog (MS) media (i.e., 4 mg of extract/mL of MS) significantly affected the root growth of A. thaliana. Roots of A. thaliana displayed weakened root tip activity and an accumulation of reactive oxygen species (ROS) in response to extracts from C. canadensis. The transcriptome analysis of A. thaliana roots exposed to phytotoxicity revealed differentially expressed genes (DEGs) involved in cell wall formation, abiotic stress, transporter genes and signal transduction. We found that genes associated with nutrient transport, such as major facilitator superfamily (MFS) and amino acid permease (AAP3) transporters as well as genes involved in stress response, including leucine-rich repeat receptor-like protein kinases (LRR-RLKs) were down-regulated. In addition, we found that many transcription factors associated with plant stress (such as APETALA2/ethylene response factors) were up-regulated while others (e.g., zinc-finger proteins) were down-regulated. Allelochemicals from C. canadensis also induced the up-regulation of detoxification (DTX) genes, ROS related genes, calcineurin B-like interacting protein kinases (CIPKs) and calmodulin. Overall, our findings provided insights into allelopathy in C. canadensis at the molecular level, and contributes to our understanding of invasion mechanisms of alien plant species. CLINICAL TRIALS REGISTRATION: This study does not contain any studies with clinical trials performed by any of the authors.