Baxter_etal_esb1_mapping

ABSTRACT: Background: Though central to our understanding of how roots perform their vital function of scavenging water and solutes from the soil, no direct genetic evidence currently exists to support the foundational model that suberin acts to form a chemical barrier limiting the extracellular, or apoplastic, transport of water and solutes in plant roots. Methodologies/Principle Findings: Using the newly characterized enhanced suberin1 (esb1) mutant, we established a connection in Arabidopsis thaliana between suberin in the root, and both water movement through the plant, and solute accumulation in the shoot. Esb1 mutants, characterized by increased root suberin, were found to have reduced day time transpiration rates, and increased water use efficiency during their vegetative growth period. Furthermore, these changes in suberin and water transport were associated with decreases in the accumulation of Ca, Mn and Zn, and increases in the accumulation of Na, S, K, As, Se and Mo in the shoot. Conclusions/Significance: Here we present direct genetic evidence establishing that suberin in the roots plays a critical role in controlling both water and mineral ion uptake and transport to the leaves. The changes observed in the elemental accumulation in leaves are also interpreted as evidence that a significant component of the radial root transport of Ca, Mn and Zn occurs in the apoplast. Keywords: genomic hybridization bulked segregant analysis Overall design: Hybridizations from a set of Bulk Segregant analysis. An F2 population from 14501 in the col-0 background crossed to Ler-0 was analyzed. This series contains the 3 hybs from Ler used to identify Single Feature Polymorphisms, the 3 hybs of Col-0 they were compared to, and 1 hyb for each pool from the BSA mapping (High Ca/B pool, low Ca/B Pool). It also included 2 tiling array hybs: a wt (Col-0) and a mutant (esb1-1).