Auxins production by radical endophytes from Populus and Nothofagus trees.

GENTILE, I; FONTENLA, S.; PARTORINO, M.J.; SEVERINO, M. E.; MESTRE, M.C

La Falda

Workshop; II Workshop Latinoamericano sobre PGPR; 2014

Root endophytes are microorganisms that during whole or part of their life cycle, colonize the plant roots without causing any disease symptoms. Some produce metabolites which promotes plant growth. Plantproduction to remediation, reforestation or forestry industry is growing in Patagonia. Different trees belonging to the genus Populus and Nothofagus are produced in nursery because of their economic and ecological importance. We collected roots from P. nigra, P. trichocarpa and N. obliqua in a nursery from INTA Bariloche. The roots were surface sterilized for culturing and isolating of endophytic bacteria. Isolation media included one general isolation medium, and selective media for diazotrophs and for Pseudomonas group. The semi-quantitative production of auxins like compounds was determined usingSalkowski method. We recovered 41 isolations of endophytic bacteria, 7 of them were assigned to the Pseudomonas group ,16 to the diazotroph group, 2 isolates were able to growth on both low N medium and cetrimide containing medium, 5 isolates showed similar colony morpholgy to Bacillus mycoides while the another 16 were assigned to a group named ?Other Bacteria?. The maximum value of auxin-like production was found within the diazotroph group with a value of ~30 μg/mL. None of the Bacillus mycoides-like isolates produced auxins at all. Most of the ?Other Bacteria? produced auxins-like compounds. Most of these endophytic bacteria produced auxins-like compounds showing their potential as plant growth promoters.