Evaluation of Indole acetic acid and hydrogen cyanide production by plant growth promoting rhizobacteria
摘要
Plant growth-promoting rhizobacteria (PGPR) enhance plant development through a sevarl mechanisms that include indole acetic acid (IAA) and hydrogen cyanide (HCN) production. This study evaluates the IAA and HCN production abilities of nine PGPR isolates, consisting of Bacillus cereus, Providencia rettgeri, Providencia vermicola, Serratia liquefaciens, and Bacillus thuringiensis. The optimization of IAA production was assessed under varying conditions, including incubation temperature, duration, pH, and tryptophan concentration. The results indicated that IAA production was significantly influenced factor investigated. Generally, peak production of IAA was observed after 48 h of incubation while tryptophan concentration was observed to be directly proportional to IAA production. With respect to pH, although no production was observed at pH levels below 6, optimal synthesis was observed at pH 7. Tat the respective temperatures investigated; the highest IAA yield was recorded at 25 °C for most of the isolates. Meanwhile, HCN production was detected after 72 h of incubation but was limited to B. cereus OP830493 and B. cereus OP830499. These findings highlight the role of PGPR in bioremediation and sustainable agriculture by reducing reliance on chemical fertilizers and pesticides. The study underscores how environmental parameters modulate IAA biosynthesis and suggests their potential application in enhancing plant growth and soil health.