An Endophytic Microbe From An Unusual Volcanic Swamp Corn Seeks And Inhabits Root Hair Cells To Extract Rock Phosphate

The study demonstrated that the bacterial endophyte strain 3F11, isolated from Zea nicaraguensis, a wild maize growing in volcanic swamps, could colonize root hairs of both annual ryegrass and corn. This endophyte promoted root hair growth and acidified the rhizosphere, facilitating the solubilization and uptake of rock phosphate (P). The GFP-tagged 3F11 cells were observed to localize on and inside root hairs, significantly increasing root hair length without affecting density. The findings suggested that 3F11's ability to target and colonize root hairs, coupled with its acid production, enhanced P uptake by increasing the root hair surface area. This dual mechanism of action was consistent across two evolutionary divergent hosts, indicating a conserved host recognition machinery. The study highlighted the potential of using such endophytes to improve P uptake in crops, especially in P-insoluble environments.