文摘
Respiratory burst oxidase homologues (Rbohs) belong to NADPH oxidase super-families and generate the initial and pivotal oxidative burst response when algae are in adverse conditions. A full-length complementary DNA (cDNA) of the Rboh gene was cloned from Pyropia haitanensis and designated as Phrboh. Phrboh has a complete open reading frame (ORF) of 2,853 base pairs, which could be translated into a polypeptide of 951 amino acids. In all red algae, Rbohs are highly conserved in their structural domains. Phylogenetic analysis showed that the red algal Rbohs cluster well into one sub-branch that is away from plant and animal counterparts. Transcription analysis showed that Phrboh was upregulated when elicited by oligoagar, heat shock, or most effectively by flg22. However, no obvious transcriptional change was detected when the gametophytes were damaged by mechanical force. In addition, the four stimulations could induce the rise of NADPH oxidase activity in P. haitanensis, but the most intense response occurred under mechanical damage. The enhancing effect of mechanical damage on the production of superoxide anion was also the largest. Heat shock induced a remarkable release of H2O2, but other stresses did not. These results indicated that the regulation of Rbohs in P. haitanensis differs under different stresses.