Metabolomics and Transcriptomics Reveal the Response Mechanisms of to Infection.

is one of the worst invasive species globally and can cause significant negative impacts on agricultural and forestry economics, particularly in Asia and the Pacific region. The rust has been used successfully as a biological control agent in several countries to help manage . However, the response mechanisms of to infection have never been studied. To investigate the response of to infection by , an integrated analysis of metabolomics and transcriptomics was performed. The levels of 74 metabolites, including organic acids, amino acids, and secondary metabolites in infected with , were significantly different compared to those in plants that were not infected. After infection, the expression of the TCA cycle gene was significantly induced to participate in energy biosynthesis and produce more ATP. The content of most amino acids, such as L-isoleucine, L-tryptophan and L-citrulline, increased. In addition, phytoalexins, such as maackiain, nobiletin, vasicin, arachidonic acid, and JA-Ile, accumulated in . A total of 4978 differentially expressed genes were identified in infected by . Many key genes of in the PTI (pattern-triggered immunity) and ETI (effector-triggered immunity) pathways showed significantly higher expression under infection. Through these reactions, is able to resist the infection of and maintain its growth. These results are helpful for us to understand the changes in metabolites and gene expression in after being infected by . Our results can provide a theoretical basis for weakening the defense response of to , and for as a long-term biological control agent of .