Plant growth promoting bacterial endophytes isolated from Polish herbal plants

Endophytes produce a wide range of compounds with high application potential, mainly in medicine and agriculture. In this study, we test the hypothesis that endophytic bacteria produce indole-3-acetic acid (IAA), have positive influence on plant root development and are possible to application as plant-growth promoters. Endophytic bacteria were isolated from 3 native growing plant species: Chelidonium majus L., Elymus repens L., Solidago gigantea L. All endophytic strains produced IAA and the highest levels of IAA were observed for Pseudomonas azotoformans P3 strain. Triticale seed bacterization did not affect the seed germination, but had significant influence on root length and the longest roots were obtained after seed treatment with Pseudomonas sp. strains. Triticale roots were longer only in seedlings grown from seeds treated with endophytic strains producing high IAA levels (more than 22 µg ml–1). Our results suggest that endophytic Pseudomonas sp. strains isolated from Elymus repens L. can be used as plant-growth promoter.