Screening of Endophytic Actinomycetes for their Plant Growth Promoting Activity and for Biocontrol in Chilli (Capsicum annum) against Sclerotium Rolfsii

In the present study, sixty endophytic actinomycetes recovered from chilli plants were evaluated for their plant growth-promoting abilities. All endophytic actinomycetes isolates were used to evaluate phosphate solubilization, siderophores, ammonia, indole-3-acetic acid and gibberellic acid production, as well as antifungal activities. Out of sixty isolates the amount of indole-3-acetic acid (IAA) ranging between 2.33�0.14 to 121.92�0.44 g/ml was produced by 37 isolates and 32 isolates were positive for ammonia production ranging between 2.24�0.04 to 22.12�0.003 mg/ml. Among sixty isolates tested, the amount of hydroxamate-type siderophores were produced by18 isolates ranging between 4.1�0.2 to 129.4�0.1 g/ml, while catechols-type siderophores produced by 9 isolates ranging from 9.2�0.2 to 147.3�0.2 g/ml. Thirteen isolates showed the solubilisation of inorganic phosphorous ranging from 1.12 � 0.04 to 20.07 � 0.02 mg/100ml, gibberellic acid production was shown by 9 ranged from 26.50�0.006 to 56.33�0.002 g/ml and 8 different isolates observed to produce HCN. The antagonistic activity was displayed by six isolates against Sclerotium rolfsii. On the basis of PGP traits and antifungal activity, isolate CR36 was selected for green house study which was identified as Streptomyces diastaticus subsp. ardesiacus. These results clearly suggest the possibility of using endophytic actinomycetes as bioinoculant for plant growth promotion, nutrient mobilization for sustainable agriculture.