Phosphorus uptake in eucalypts plants under split root system

Phosphorus (P) often limits plant growth and development because its availability in most soils is low, mainly in tropical soils. Various phosphate transporters and regulatory elements, including transcription factors, are involved in the uptake and transport of P from the soil into root cells and to other plant organs. The split-root technique was applied to three eucalypt species to understand better the mechanisms of the root-leaf signaling and remobilization response to P supply. Two-month-old seedlings of Eucalypts grandis, E. globulus , and E. tereticornis were used, with each half of the split root system placed in pots. The P treatments were: +P/+P, +P/-P, and -P/-P (+ P = P supplementation and –P = P depleted). P was supplied as 440 µM nutrient solution. Eucalypts plants were grown for six weeks and RT-qPCR evaluated the expression of genes related to P uptake, transport, and utilization in roots and leaves. P supply on one side of the root seemed to compensate for the lack of P on the other side in the + P/-P treatment, so the plant did not show P stress responses, and root-to-root signaling and remobilization in this treatment differed depending on the species. The genes analyzed were mostly induced when plants were under P deprivation, and the expression response was species-dependent. Therefore, this indicates that different mechanisms may be involved in plant response to low P and that signaling control 1may also be linked to the adaptation of eucalypts species to low soil P.