INDOLE-3-ACETIC ACID (IAA) PRODUCTION BY ENDOPHYTIC BACTERIA ISOLATED FROM SALINE DESSERT, THE LITTLE RUNN

A total of 13 isolates were screened for their potential to produce IAA and all isolates were able to utilize tryptophan and produce the IAA. The two isolates with high IAA production were secondary screened to select the most highest producer. Isolation of microorganisms was carried out from root samples of different plants collected from saline desert, Little Rann of Kachchh. Isolation was carried out by enrichment isolation technique using YEM (Yeast Extract Mannitol) agar and ASM (Ashby’s Mannitol) Agar. TLC and FTIR analysis confirmed the IAA production in the cell filtrates of the strain. Sequencing of the 5AY isolate had 16S rRNA gene with 99% nucleotides identity to that of Pseudomonas stutzeri, and 10AY isolate had 16S rRNA gene with 99% nucleotides identity to that of Bacillus sp. TA_AJ2. IAA production by Pseudomonas stutzeri and Bacillus sp. TA_AJ2was optimized by studying some factors and the results revealed that the maximum IAA value was obtained when the isolate cultivated in tryptone yeast extract broth medium supplemented by tryptophane 200µg/ml, incubated at 37°C for 168 hours. These results suggest that IAA-producing Pseudomonas stutzeri could be a promising candidate for utilization in growth improvement of plants of economic and agricultural value.