Though both strains (A3CK and A7CK) were able to produce IAA
from all the isomers oftryptophan, they preferred L-tryptophan for
growth and IAA production (data not shown). The highest IAA
production in culture was recorded at 2mg/ml tryptophan level
for both the strains(Fig. 2B).Tryptophan is a known precursor of
IAA biosynthetic pathways (Spaepen etal.,2007). The indole-3-
pyruvate pathway was found in E. cloacae where thetryptophan
was also precursor in IAA biosynthesis (RyuandPatten,2008).