Endophytic microorganisms isolated from coffee leaves, roots and branchesas plant growth promoters and biocontrol agents of coffee leaf rust


Abstract: Suppression of plant diseases and growth promotion due to the action of endophyticmicroorganisms has been demonstrated in several pathosystems. Experiments under controlledconditions involving 234 endophytic bacteria and fungi isolated from coffee leaves, roots andbranches were conducted with the objective of evaluating the germination inhibition of Hemileiavastatrix urediniospores, the control of coffee leaf rust development in tests with leaf discs andon plastic bags seedling, and to promote growth of coffee seedlings. None of the fungal isolatesinduced plant growth or reduced disease severity. The bacterial isolates (identified by the fattyacids profile analysis) 85G (Escherichia fergusonii), 161G, 163G, 160G, 150G (Acinetobactercalcoaceticus) and 109G (Salmonella enterica) increased plant growth, the maximum beinginduced by 85G. This isolate produced in vitro phosphatase and indol acetic acid. In assay tocontrol rust on coffee leaf disc, nine bacterial isolates, 64R, 137G, 3F (Brevibacilluschoshinensis), 14F (Salmonella enterica), 36F (Pectobacterium carotovorum), 109G (Bacillusmegaterium), 115G (Microbacterium testaceum), 116G and 119G (Cedecea davisae)significantly reduced disease severity, when applied 72 or 24h before challenging with thepathogen. In seedling tests most disease severity reduction was achieved by the isolates 109G and119G. There was no correspondence between the organisms that promoted seedling growth andthose that reduced rust severity on seedlings or leaf discs.

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