Sugarcane Seedling Growth Promotion by Indole Acetic Acid (IAA) Producing Streptomyces sp. AS14-2 Isolated from Rhizosphere of Sugarcane and Rice

Abstract

The present study aimed to screen and identify of indole acetic acid (IAA) producing actinomycetes isolates from the rhizosphere of sugarcane and rice and to evaluate the effects of these isolates on plant growth under pot experiment conditions. Out of eleven IAA producing actinomycete isolates, two isolates include AS13-2 and AS14 showed the highest ability to produce IAA 29.02 and 17.17µg/mL respectively. Based on morphological and 16S rDNA sequence analysis indicated these isolates belong to Streptomyces genus. Pot culture experiments revealed that sugarcane seedlings inoculated with the IAA producing Streptomyces sp. AS14-2 gave the best enhancement of plant growth and significantly increased shoot lengths, shoot fresh weight, shoot dry weight, root lengths, root fresh weight and root dry weight compared with un-inoculated control treatments. These results suggest that the IAA producing Streptomyces sp. AS14-2 could be a promising candidate for utilization in growth improvement in sugarcane crop.