The horticulture department at Purdue University led a team of international researchers studying auxin transport and how PIN and PGP proteins work together to direct plant growth.
Auxin is the hormone that signals growth in both roots and shoots. PIN-PGP complexes direct the flow of auxin as it influxes at the apex of a plant cell and effluxes at the basal end. The arrangement of the complexes mechanically directs auxin flow, and the changing concentrations of auxin turn genes on and off locally to initiate shoots and roots.
With greater understanding of these protein complexes, it may be possible to “direct” auxin flow and control root:shoot ratios and engineer plants used for biofuels.