Glabrous Rice 1, encoding a homeodomain protein, regulates trichome development in rice

Background: Glabrous rice, which lacks trichomes on the rice epidermis, is regarded as an important germplasm resource in rice breeding. Trichomes are derived from aerial epidermal cells and used as a model to study the cell fate determination in plant. In Arabidopsis, the molecular mechanisms of trichome development have been well studied. However, little is known about the molecular basis of trichome development in rice. Results: In this study, near isogenic lines harboring the glabrous rice 1 locus were developed. By a map-based approach, we narrowed down the locus to a 21-kb DNA region harboring two genes. One of the genes named Glabrous Rice 1 (GLR1), which is most likely the candidate, encodes a homeodomain protein containing the WOX motif. Constitutive Expression of GLR1 could partially complement the glabrous phenotype of NILglr1. The knock down of GLR1 by RNA interference led to a significant decrease in trichome number on the leaves and glumes of the RNAi transgenic plants. Conclusion: GLR1 plays an important role in rice trichome development and will contribute to breeding of glabrous elite rice varieties.