Endophytic bacteria from paddy with double 1-aminocyclopropane-1-carboxylic acid deaminase and nitrogenase activity

Abstract

Plant growth promoting bacteria with dual activity, 1-aminocyclopropane-1-carboxylic-acid deaminase (ACCD) and nitrogenase, is more effective in supporting plant growth under stress condition. Previously, we were obtained several endophytic bacterial strains that exhibited dual activity, one of which was Raoultella terrigena PCM8. This study aimed to characterize the ACCD and nitrogenase genes of PCM8 strain. The acdS gene was obtained from the results of Whole Genomic Sequencing analyis, while the nifH gene was obtained by PCR. The characterization of both of the genes was carried out by means of in-silico analysis. WGS annotation analysis, showed that the acdS gene of PCM8 was located at the locus 19090 of genomic DNA and contains 978 nucleotides. In silico analysis of both acdS and nifH gene products showed that the ACCD enzyme of PCM8 had 325 amino acids, with molecular weight of 34.95 kDa, while nitrogenase as represented by nifH subunit product consist of 96 amino acids with molecular weight of 93.98 kDa, respectively.  The ACCD had pI value of 5.06, and catalytic residues of Lys51, Ser78, Tyr287, and Thr288, while nifH gene product had the pI value of 11.77. The results suggested that R. terrigena PCM8 potentially produce double activity of ACCD and nitrogenase and therefore it can be a good candidate as plant growth promoting under stress condition.

Keywords: acdS gene, 1-aminocyclopropane-1-carboxylic acid deaminase, endophytic bacteria, nifH gene, nitrogenase Raoultella terrigena