A Major Locus for Chloride Accumulation on Chromosome 5A in Bread Wheat

Abstract

Chloride (Cl−) is an essential micronutrient for plant growth, but can be toxic at high concentrations resulting in reduced growth and yield. Although saline soils are generally dominated by both sodium (Na+) and Cl− ions, compared to Na+ toxicity, very little is known about physiological and genetic control mechanisms of tolerance to Cl− toxicity. In hydroponics and field studies, a bread wheat mapping population was tested to examine the relationships between physiological traits [Na+, potassium (K+) and Cl− concentration] involved in salinity tolerance (ST) and seedling growth or grain yield, and to elucidate the genetic control mechanism of plant Cl− accumulation using a quantitative trait loci (QTL) analysis approach. Plant Na+ or Cl− concentration were moderately correlated (genetically) with seedling biomass in hydroponics, but showed no correlations with grain yield in the field, indicating little value in selecting for ion concentration to improve ST. In accordance with phenotypic responses, QTL controlling Cl− accumulation differed entirely between hydroponics and field locations, and few were detected in two or more environments, demonstrating substantial QTL-by-environment interactions. The presence of several QTL for Cl− concentration indicated that uptake and accumulation was a polygenic trait. A major Cl− concentration QTL (5A; barc56/gwm186) was identified in three field environments, and accounted for 27–32% of the total genetic variance. Alignment between the 5A QTL interval and its corresponding physical genome regions in wheat and other grasses has enabled the search for candidate genes involved in Cl− transport, which is discussed.

Ion‐dependent metabolic responses of Vicia faba L. to salt stress

“…The third aim of this study was to identify ion-specific effects by a comparative metabolite analysis; such effects are otherwise difficult to identify (Genc, Oldach, Taylor, & Lyons, 2016;Genc, Taylor, Rongala, & Oldach, 2014). We assume that if one metabolite increased in two salt treatments that shared the Na + ion (e.g., NaCl and Na 2 SO 4 ) but not in the third salt (i.e., KCl), then this effect is probably caused by Na + .…”

AtNPF2.5 Modulates Chloride (Cl−) Efflux from Roots of Arabidopsis thaliana

“…Genotypic differences in Cl − efflux from the root of salt sensitive and salt tolerant poplar species demonstrated the contribution of salt-inducible Cl − excretion from the root to plant salinity tolerance (Sun et al, 2009). The exclusion of Cl − has been found to be a multigenic trait (Gong et al, 2011; Long et al, 2013; Genc et al, 2014), and this is not surprising considering the many potential processes that can underpin Cl − transport to the shoot that are detailed above.…”

Ncl Synchronously Regulates Na+, K+ and Cl− in Soybean and Greatly Increases the Grain Yield in Saline Field Conditions

“…In contrast, mechanisms of chloride (Cl − ) transport in plants are poorly understood, despite the importance of minimizing Cl − toxicity for salt tolerance. Control of Cl − transport and Cl − “exclusion” from shoots is correlated with salt tolerance in soybean 1 7 11 13 32 and other legumes Trifolium 33 , Medicago 34 , and Lotus 35 as well as in other crops, such as wheat 36 ; however, no gene that regulates the transport and accumulation of Cl − in soybean has been reported.…”