Phosphate solubilizing bacteria associated with the rhizosphere of yacón [Smallanthus sonchifolius (Poeppig) Robinson] and its ability to promote plant growth

Abstract

In recent years, research in plant species for nutraceutical purposes has increased. The biotechnological development allows the use of microorganisms in the production of edible value crops and medicinal properties such as yacon (Smallanthus sonchifolius). The aim of this work is to contribute to the knowledge of the association of the bacteria to its
rhizosphere and its capacity to promote plant growth. In order to do this, phosphate-solubilizing bacteria were isolated from the yacon rhizosphere. Solubilization index of tricalcium phosphate and the ability to solubilize other phosphates (iron phosphate, aluminum phosphate and basis slag), to produce total indoles and siderophores were evaluated. The organic acids produced were identified and the effect on plant growth was evaluated. Propagules with three vegetative buds were inoculated by immersion in the bacterial suspensions. They were planted in pots and placed in a greenhouse
for 90 days. The isolated characterized as YM1, YM2 and YM3 solubilized tricalcium phosphate, iron phosphate and basis slag. All produced total indoles and siderophores. YM1 and YM3 showed significant differences in stem length, number of leaves, dry weight, length and dry weight of roots. The results suggest that these isolated could be promising for their use, as growth promoters, in yacon.