Histological characterization of the lateral root primordium development in rice

Background: Lateral root constitutes an important part of root system either in tap root plants or fibrous root plants. The development of lateral root primordium (LRP) in Arabidopsis, which has a tap root system with simple radial structure of primary root, has been well characterized. However, limited knowledge has been acquired on the plants with fibrous root system, such as rice. This is mainly due to their multiple cell layers coated on root, which disturb the observation of LRP. Results: We used an easy and quick method to strip the epidermal and cortex tissues of primary root so that the LRP can be easily observed under microscope. In this way, we observed the developmental processes of LRP in rice. In addition, we described the expression dynamics of several root development related genes, especially OsPINs (PIN-FORWMED), during the process of LRP development. Conclusions: We reported an easy and quick method for LRP observation in rice and suggested a fountain model of auxin transport in LRP of rice, which is similar with that in Arabidopsis.