Screening of ApDOT1.9 interacting proteins and the potential function of interactor ApSNARE in the rapid growth regulation of Alexandrium pacificum

Alexandrium pacificum is a toxic dinoflagellate resulting in harmful algal blooms (HABs). ApDOT1.9 is a methyltransferase involved in the rapid growth regulation of A. pacificum, but its protein interaction information is still limited. In this study, 14 candidate interacting proteins of ApDOT1.9, which were involved in metabolism, genetic information processing, environmental information processing and cellular processes, were screened. The interaction between candidate interactor ApSNARE (Soluble N-ethylmaleimide-sensitive factor attachment protein receptors of Alexandrium pacificum) and ApDOT1.9 was further validated by molecular docking and GST (Glutathione S transferase) pull-down. The relevant biological functional information and gene expression of ApSNARE were also analyzed and detected. These results indicate that ApSNARE was an interactor of ApDOT1.9 and it may also participate in A. pacificum rapid growth regulation under high light or high nitrogen conditions, which will provide preliminary information on the interaction proteins of ApDOT1.9 and molecular regulation mechanisms of growth in A. pacificum. •Candidate interacting proteins of ApDOT1.9 in A. pacificum were screened by GST pull-down combined mass spectrometry;•ApSNARE interaction with ApDOT1.9 was confirmed by molecular docking and in vitro GST pull-down;•The interactor ApSNARE may be involved in the rapid growth of A. pacificum under high light or high nitrogen conditions.