RPE, a plant gene involved in early developmental steps of nematode feeding cells

Sedentary plant-parasitic nematodes are able to induce the redifferentiatio n of root cells into multinucleate nematode feeding sites (NFSs), We have i solated by promoter trapping an Arabidopsis thaliana gene that is essential for the early steps of NFS formation induced by the root-knot nematode Mel oidogyne incognita. Its pattern of expression is similar to that of key reg ulators of the cell cycle, but it is not observed with the cyst nematode. L ater in NFS development, this gene is induced by both root-knot and cyst ne matodes. It encodes a protein similar to the D-ribulose-5-phosphate 3-epime rase (RPE) ((EC 5.1.3.1), a key enzyme in the reductive Calvin cycle and th e oxidative pentose phosphate pathway (OPPP), Quantitative RT-PCR showed th e accumulation of RPE transcripts in potato, as in Arabidopsis NFS, Homozyg ous rpe plants have a germination mutant phenotype that can be rescued in d warf plants on sucrose-supplemented medium. During root development, this g ene is expressed in the meristems and initiation sites of lateral roots. Th ese results suggest that the genetic control of NFSs and the first stages o f meristem formation share common steps and confirms the previous cytologic al observations which indicate that root cells undergo metabolic reprogramm ing when they turn into NFSs.