New study reveal another nutrition process involving plant roots and symbiotic microorganisms. The roots use their exudate to attract bacterias within the periplasmic spaces, the bacteria is then used as food. The surviving microorganisms are then ejected through roots hair and start again a cycle of regeneration and re-ingestion by the plant. This new study represent a milestone in the understanding of plant nutrition and quantitative analysis need to be performed in order to define the extent of this nutrition process.
Abstract can be found here: https://www.mdpi.com/2076-2607/6/3/95