Rhizogenesis Lab - Projects ................................
Role of auxin in root system development
in C. glauca
Dr. Laurent Laplaze - Dr. Benjamin Péret
Actinorhizal nodules and proteoïd roots are modified lateral roots and it is well documented that auxin controls lateral root development. Therefore, we are investigating the role of auxin during lateral root, proteoïd roots, and nodule development in Casuarina glauca.
1. Auxin distribution during lateral root and nodule development in C. glauca
We are trying to develop molecular markers to visualise auxin distribution during lateral root development. Transgenic Casuarinaceae
containing the PDR5-GUS and PIAA2-GUS markers have been generated. They
will be used to analyse changes in auxin concentration during the early
stages of lateral root and nodule formation.
2. Role of auxin transport during C. glauca root and nodule development
The LAX genes (including AUX1) code for auxin influx carriers. Marchant et al. (2002) have shown that AUX1
regulates lateral root development. In collaboration with Pr. M.
Bennett's laboratory in Nottingham (Projet Alliance n°05752SM), we
have isolated 2 homologues of LAX genes in C. glauca (named CgAUX1 and CgLAX3 according to their homology to Arabidopsis genes).
We are now studying the expression pattern of CgAUX1 and CgLAX3 during lateral root and nodule development in C. glauca. Moreover, complementation of the aux1 mutant using C. glauca LAX genes is underway.