The biochemical characterisation of bacterial serine proteases and their influence on nitrogen acquisition in Zea mays

Nitrogen (N) is a vital element of life. Since plants cannot use or take atmospheric N, they uptake nitrogen in the form of ammonium and nitrate. The conversion of N to
multiple chemical forms is microbial-dependent. We have identified bacterial members
associated with maize roots that secrete active proteases. Genes for proteolysis are significantly more abundant in root-associated bacteria than in soil and certain classes of proteases are highly expressed in endophytic bacterial communities. This body of evidence indicates that plants might “select” for bacterial strains that promote an advantage under certain conditions, e.g. availability of nitrogen. We hypothesize that bacterial proteases can improve nitrogen acquisition under poor nitrogen conditions and that plants recruit bacteria-producing proteases to enhance plant nitrogen uptake.

Here, we aim to investigate the proteases produced in the maize root-associated SynCom cultures Stenotrophomonas maltophilia, Chryseobacterium indologenes, and Curtobacterium pusillum. Furthermore, we will test their effect on Mono- and Dicots on different nitrogen sources.