SUPRA-PHYSIOLOGICAL LEVELS OF GIBBERELLINS / DELLAS ALTER THE PATTERNING, MORPHOLOGY AND ABUNDANCE OF ROOT HAIRS IN ROOT TIPS OF ARABIDOPSIS THALIANA SEEDLINGS

Abstract

In spite of the role of gibberellins/DELLAs in leaf hair production, no investigations have assessed their function in the production of root hairs. To this aim, the effects of supra-physiological levels of GAs/DELLAs on the gene expression patterning of the root hair (CPC) and non-hair (GL2, EGL3 and WER) epidermal cell fate markers, and on the distribution, morphology and abundance of root hairs, were studied in root tips of 5-day-old A. thaliana seedlings. Results showed that excessive GAs/DELLAs misarranged the CPC, GL2, EGL3 and WER gene expression patterning and the location, shape and frequency of root hairs. However, when the gai-1 (GA-insensitive-1) DELLA mutant protein was specifically over-expressed at the root epidermis, no changes in the patterning or abundance of root hairs occurred. Thus, results suggest that, in A. thaliana seedlings, the GAs/DELLAs might regulate the patterning, morphology and abundance of root hairs from the sub-epidermal tissues of the root.

Keywords

• dellas
• gibberellins
• root hair morphology
• root hair number
• root hair patterning