The wheat Phs-A1 pre-harvest sprouting resistance locus delays the rate of seed dormancy loss and maps 0.3 cM distal to the PM19 genes in UK germplasm

Shorinola, Oluwaseyi; Bird, Nicholas; Simmonds, James; Berry, Simon; Henriksson, Tina; Jack, Peter; Werner, Peter; Scholefield, Duncan; Balc�rkov�, Barbara; Val�rik, Miroslav; Holdsworth, Michael J.; Flintham, John; Uauy, Christobal

Abstract

The precocious germination of cereal grains before harvest, also known as pre-harvest sprouting, is an important source of yield and quality loss in cereal production. Pre-harvest sprouting is a complex grain defect and is becoming an increasing challenge due to changing climate patterns. Resistance to sprouting is multi-genic, although a significant proportion of the sprouting variation in modern wheat cultivars is controlled by a few major quantitative trait loci, including Phs-A1 in chromosome arm 4AL. Despite its importance, little is known about the physiological basis and the gene(s) underlying this important locus. In this study, we characterized Phs-A1 and show that it confers resistance to sprouting damage by affecting the rate of dormancy loss during dry seed after-ripening. We show Phs-A1 to be effective even when seeds develop at low temperature (13 °C). Comparative analysis of syntenic Phs-A1 intervals in wheat and Brachypodium uncovered ten orthologous genes, including the Plasma Membrane 19 genes (PM19-A1 and PM19-A2) previously proposed as the main candidates for this locus. However, high-resolution fine-mapping in two bi-parental UK mapping populations delimited Phs-A1 to an interval 0.3 cM distal to the PM19 genes. This study suggests the possibility that more than one causal gene underlies this major pre-harvest sprouting locus. The information and resources reported in this study will help test this hypothesis across a wider set of germplasm and will be of importance for breeding more sprouting resilient wheat varieties.

• Journal Article Type: Article
• Acceptance Date: Apr 25, 2016
• Online Publication Date: May 23, 2016
• Publication Date: Jul 1, 2016
• Deposit Date: Nov 24, 2016
• Publicly Available Date: Nov 24, 2016
• Journal: Journal of Experimental Botany
• Print ISSN: 0022-0957
• Electronic ISSN: 1460-2431
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 67
• Issue: 14
• Pages: 4169-4178
• DOI: https://doi.org/10.1093/jxb/erw194
• Keywords: After-ripening, dormancy, PM19, pre-harvest sprouting, seed, synteny, Triticum aestivum
• Public URL: https://nottingham-repository.worktribe.com/output/788999
• Publisher URL: http://jxb.oxfordjournals.org/content/67/14/4169