Plant root phenolic acids play multifunctional roles plantmicrobe interactions in rhizospheric region. The in fluence of root
nodule phenolic acid son IAA production by its symbiontis
observed (Mandal etal.,2009). Therefore,the effect of phenolic
acids on IAA production was tested in culture condition (Table7).
The result in dicates that most of the phenolic acids in hibit growth
and IAA production except protocatechuic acid for the strain A3CK
and ferulic acid for the strain A7CK are the best stimulant at 1 mg/
ml concentration for IAA production (Fig. 4A andB). Protocatechuic acid is also shown to stimulate IAA production maximally at
1 mg/ml in rhizobial isolates of the root nodule of Vigna mungo
(Mandal etal.,2009). Phenolic acids are found strain specific vital
agents that could modify the legume–bacterial symbiosis
Seneviratne and Jayasinghearachchi(2003). Moreover,phenolic
acids also have stronganti-oxidativeproperty by keep in gmetal
ions (Mn2þ and Fe3þ) at reduced state,that in turn regulate the
IAA oxidase and peroxidase for stimulation of IAA production
(Schneider and Wightman,1974). Further,it was found that
optimization of nutritional requirements by supple mentation of
the different nutrients in medium ; the IAA production was
enhanced in culture.In optimized medium the strains A3CK and
A7CK produced 478 mg/ml and 545 mg/ml of IAA and are 236.6%
and 251.6% enhancement from the basal medium,respectively