Kacper Piotr Kaminski, Kirsten Kørup, Mathias Neumann Andersen, Mads Sønderkær, Mette Sondrup Andersen, Hanne Grethe Kirk, Kåre Lehmann Nielsen

Theoretical and Applied Genetics, November 2015, Volume 128, Issue 11, pp 2143-2153

Abstract

Key message

WUE phenotyping and subsequent QTL analysis revealed cytosolic GS genes importance for limiting N loss due to photorespiration under well-watered and well-fertilized conditions.

Abstract

Potato (Solanum tuberosum L.) closes its stomata at relatively low soil water deficits frequently encountered in normal field conditions resulting in unnecessary annual yield losses and extensive use of artificial irrigation. Therefore, unraveling the genetics underpinning variation in water use efficiency (WUE) of potato is important, but has been limited by technical difficulties in assessing the trait on individual plants and thus is poorly understood. In this study, a mapping population of potatoes has been robustly phenotyped, and considerable variation in WUE under well-watered conditions was observed. Two extreme WUE bulks of clones were identified and pools of genomic DNA from them as well as the parents were sequenced and mapped to reference potato genome. Following a novel data analysis approach, two highly resolved QTLs were found on chromosome 1 and 9. Interestingly, three genes encoding isoforms of cytosolic glutamine synthase were located in the QTL at chromosome 1 suggesting a major contribution of this enzyme to photosynthetic efficiency and thus WUE in potato. Indeed, Glutamine synthetase enzyme activity of leaf extracts was measured and found to be correlated with contrasting WUE phenotypes.

See: http://link.springer.com/article/10.1007/s00122-015-2573-2

Figure 2: Relative skewness measure (all scaled to the same value of relative contribution to skewness) of low and high bulk mapping marker distribution on 12 reference potato genome chromosomes. Sliding window analysis was performed with bin size of 2 Mb and step size of 0.2 Mb. Two overlapping peaks in low and high bulks were detected, at chr. 01 〈24.7;27.5〉 and at chr. 09 〈39.5;43.1〉