Auxins production
The auxins production in the presence of 50% v/v Trichodermaspp. was quantified using the Salkowski reagent . Bacterial cultures (5
ml) at initial OD600 0.1 were grown at 30°C overnight in
TY medium supplemented with 1.25 mM L-tryptophan and 50% v/v fungal
spent medium. After 24 h, cell cultures were centrifuged at 10,000 rpm
for 10 minutes. The culture supernatants and the Salkowski reagent
(distilled water 300 ml, 95-97% H2SO4180 ml, 0.5 M FeCl3 9 ml) were mixed (1:4 ratio) and
incubated in the dark for 30 min at room temperature. The absorbance was
estimated at 530 nm with a spectrophotometer. The auxins concentration
in cultures was estimated based on the IAA standard curve. Four
biological replicates (independent cultures) were performed. Production
inhibition index was calculated as: 1- OD530trt/OD530 ctr where OD represents the values of optical
density at 530 nm for treated (trt) and control (ctr) samples.