02333naa a2200265 a 450000100080000000500110000800800410001902400520006010000200011224501380013226000090027052014980027965300240177765300200180165300360182165300240185770000170188170000250189870000160192370000200193970000150195970000190197470000200199377300540201321200092021-01-08       2020    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1007/s11104-019-04388-02DOI1 aFERREIRA, N. S.  aInteraction of phytohormone-producing rhizobia with sugarcane mini-setts and their effect on plant developmenth[electronic resource]  c2020  aRhizobia are common members of plant microbiomes. This study aimed to evaluate if rhizobia can colonize sugarcane mini-setts and if and how they affect sprouting and morphological traits of plant development. Bradyrhizobium sacchari strain BR 10280T and Rhizobium sp. strain BR 10268 were inoculated on sugarcane mini-setts and sprouting and plant development were evaluated. Bacterial production of hormones and their effect on plant growth were studied using HPLC and GC-MS / SIM and sugarcane sprouting assays. Colonization was investigated by colony counting and CLSM. Sequence analysis of recA, gyrB and rpoB genes was applied to refine the phylogenetic classification of strain BR 10268. Results BR 10268 had a positive effect on sugarcane mini-sett sprouting and shoot and root growth at 30 and 75 days after transplantation (DAT) and colonized sprouting mini-sett tissues. Few significant effects were observed for B. sacchari BR 10280T . Cell-free BR 10268 supernatant was found to contain gibberellins (GAs) and low concentrations of indole-3-acetic acid (IAA) and trans-zeatin; treatment of mini-setts with GA3 (0.15 or 1.5 μg mL−1 ) affected sprouting in a similar manner as BR 10268 inoculation. BR 10268 was found to be phylogenetically close to R. freirei Rhizobium sp. BR 10268 positively affects h of sugarcane, probably via production of plant hormonal substances, notably gibberellins, thus naturally occurring rhizobia may have potential as sugarcane inoculants.  aEndophytic bacteria  aGibberellins HP  aPlant growth promoting bacteria  aScanning microscopy1 aMATOS, G. F.1 aMENESES, C. H. G. de1 aREIS, V. M.1 aROUWS, J. R. C.1 aSCHWAB, S.1 aBALDANI, J. I.1 aROUWS, L. F. M.  tPlant and Soil, Published online 3 January, 2020.