Abstract
Mineral starvation is though to reduce plant growth by reducing metabolic activity, however this might be an oversimplified view. By using the Arabidopsis natural variation we have identified a major QTL (LPR1 = Low Phosphate Response1), and its paralogue LPR2, that reduce the primary growth during phosphate stavation. The molecular origin of the LPR1 QTL is explained by the differential allelic expression of LPR1 in the root tip (1,2,3). Physical contact of the primary root tip with low-Pi medium is required to arrest root growth. These results provide strong evidences for the involvement of the root cap in sensing and/or responding to mineral deficiency. Our results suggest that when the root encounters a mineral-deficient zone, a signaling pathway restraining growth is triggered in the root tip. We are currently dissecting this signalling by various approaches including classical (4) and chemical genetics, microscopy, biochemistry (5,6) and new tools to manipulate phosphate flux in vivo.
1 Reymond et al. 2006. PCE, 2 Svistoonoff et al. 2007. Nature Genet., 3 Ticconi et al. 2009. PNAS, 4 Misson et al. 2004. PMB, 5 Misson et al. 2005. PNAS, 6 Hirsch et al. 2006. Biochimie
