title: Studies on the factors modulating indole-3-acetic acid production in endophytic bacterial isolates from Piper nigrum and molecular analysis of ipdc gene.
abstract: OBJECTIVE
  The study mainly aimed quantitative analysis of IAA produced by endophytic bacteria under various conditions including the presence of extract from Piper nigrum. Analysis of genetic basis of IAA production was also conducted by studying the presence and diversity of the ipdc gene among the selected isolates.
  
  
  METHODS
  Five endophytic bacteria isolated previously from P. nigrum were used for the study. The effect of temperature, pH, agitation, tryptophan concentration and plant extract on modulating IAA production of selected isolates was analysed by colorimetric method. Comparative and quantitative analysis of IAA production by colorimetric isolates under optimal culture condition was analysed by HPTLC method. Presence of ipdc gene and thereby biosynthetic basis of IAA production among the selected isolates were studied by PCR-based amplification and subsequent insilico analysis of sequence obtained.
  
  
  CONCLUSIONS
  Among the selected bacterial isolates from P. nigrum, isolate PnB 8 (Klebsiella pneumoniae) was found to have the maximum yield of IAA under various conditions optimized and was confirmed by colorimetric, HPLC and HPTLC analysis. Very interestingly, the study showed stimulating effect of phytochemicals from P. nigrum on IAA production by endophytic bacteria isolated from same plant.
  
  
  CONCLUSIONS
  This study is unique because of the selection of endophytes from same source for comparative and quantitative analysis of IAA production under various conditions. Study on stimulatory effect of phytochemicals on bacterial IAA production as explained in the study is a novel approach. Studies on molecular basis of IAA production which was confirmed by sequence analysis of ipdc gene make the study scientifically attractive. Even though microbial production of IAA is well known, current report on detailed optimization, effect of plant extract and molecular confirmation of IAA biosynthesis is comparatively novel in its approach.
authors.affiliation: School of Biosciences, Mahatma Gandhi University, Kottayam, India.
authors.forename: B
authors.initials: B
authors.lastname: Jasim
authors.forename: C
authors.initials: C
authors.lastname: Jimtha John
authors.forename: V
authors.initials: V
authors.lastname: Shimil
authors.forename: M
authors.initials: M
authors.lastname: Jyothis
authors.forename: E K
authors.initials: EK
authors.lastname: Radhakrishnan
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000737:chemistry / Q000235:genetics*; D060026:Endophytes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005798:Genes, Bacterial; D007210:Indoleacetic Acids / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000235:genetics; D010802:Phylogeny; D029222:Piper nigrum / Q000382:microbiology*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein
chemical_list: D007210:Indoleacetic Acids; C030737:indoleacetic acid; C068832:indolepyruvate decarboxylase; D002262:Carboxy-Lyases
keywords: HPTLC; IAA production; Piper nigrum; endophytes; ipdc gene; piperine