| Anabaena sp.PCC 7120 is a photoautotrophic filamentous cyanobacteria.In the absence of available combined nitrogen sources(e.g.,ammonium,nitrate,etc.),Anabaena sp.PCC 712 can form semi-regularly distributed heterocyst cells in filaments and perform nitrogen fixation.Therefore,Anabaena sp.PCC 7120 has become a model organism to study the nitrogen fixation,carbon/nitrogen balance,and cell differentiation.However,the molecular mechanism and regulatory network of Anabaena sp.PCC 7120 in response to nitrogen deficiency stress are still unclear.In this study,we employed a label-free quantitative proteomic strategy to systematically investigate the nitrogen deficiency response of Anabaena sp.PCC 7120 at different time points.In total,363,603,and 669 proteins showed significant changes in protein abundance under nitrogen deficiency for 3,12,and 24 h,respectively.Bioinformatics analysis of differentially expressed proteins(DEPs)showed that these proteins were involved in various biological processes,including photosynthesis,nitrogen fixation,heteromorphic differentiation and energy metabolism.The expression of 10 proteins related to heterocysts differentiation at different time points was further validated by using multiple reaction monitoring(MRM)assays.Transcriptome and proteome data were combined to analyze the strategies of response to nitrogen deficiency stress at different levels.In particular,many dysregulated proteins were found to be time-specific and annotated as unknown or hypothetical,providing new candidates for future functional studies in this model cyanobacterium.In summary,this study revealed the dynamic response strategies of Anabaena sp.PCC 7120 under nitrogen deficiency stress,supplementing the analysis of key proteases in the regulatory network of nitrogen deficiency response,and provide novel insights into the molecular mechanisms of nitrogen stress responses and heterocyst development in Anabaena sp.PCC 7120. |
PDF Full Text Request