Transcriptional regulation and expression networks involving exogenous nitric oxide in Kentucky bluegrass under cadmium stress

Cadmium (Cd) is harmful to the environment, as it is a non-essential biological element. It leads to the normal dysfunction and degradation of soil quality, and is toxic to plants. Many studies reported that the application of nitric oxide (NO) can effectively reduce the toxicity of Cd in plants. However, the underlying molecular mechanism of the positive effects of exogenous NO on plant Cd tolerance has not been well documented. In the present study, comparative transcriptome analysis was performed on Kentucky bluegrass seedlings treated with Cd (Cd alone) and Cd + NO (Cd and NO simultaneously) .Comparative transcriptional regulation analysis showed that Differential expressed genes (DEGs) was mainly involved in mitogen-activated protein kinase (MAPK) signal transduction, plant hormone signal transduction, phenylpropanoid biosynthesis, amino acid transport and metabolism, fatty acid metabolism and biosynthesis related pathways. These results suggest that exogenous NO may alleviate cadmium stress by regulating genes related to signal transduction, carbohydrate transport and metabolism, amino acid biosynthesis and phenylpropane biosynthesis. Additionally, the DEGs and metabolic pathways between Cd and Cd + NO treatment groups were analyzed in this study, and a series of key genes mediated by NO signal in response to cadmium stress were screened out, and they were listed as candidate genes related to NO alleviating cadmium stress in Kentucky bluegrass. This study helps to understand the transcriptional regulation and complex internal network of exogenous NO alleviating Cd -tolerance in Kentucky bluegrass.