A distorted circadian clock causes early flowering and temperature-dependent variation in spike development in the Eps-3Am mutant of einkorn wheat

Piotr Gawroński, Ruvini Ariyadasa, Axel Himmelbach, Naser Poursarebani, Benjamin Kilian, Nils Stein, Burkhard Steuernagel, Goetz Hensel, Jochen Kumlehn, Sunish Kumar Sehgal, Bikram S. Gill, Peter Gould, Anthony Hall, Thorsten Schnurbusch

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


Viable circadian clocks help organisms to synchronize their development with daily and seasonal changes, thereby providing both evolutionary fitness and advantage from an agricultural perspective. A high-resolution mapping approach combined with mutant analysis revealed a cereal ortholog of Arabidopsis thaliana LUX ARRHYTHMO/PHYTOCLOCK 1 (LUX/PCL1) as a promising candidate for the earliness per se 3 (Eps-3Am) locus in einkorn wheat (Triticum monococcum L.). Using delayed fluorescence measurements it was shown that Eps-3Am containing einkorn wheat accession KT3-5 had a distorted circadian clock. The hypothesis was subsequently confirmed by performing a time course study on central and output circadian clock genes, which showed arrhythmic transcript patterns in KT3-5 under constant ambient conditions, i.e., constant light and temperature. It was also demonstrated that variation in spikelet number between wild-type and mutants is sensitive to temperature, becoming negligible at 25°. These observations lead us to propose that the distorted clock is causative for both early flowering and variation in spike size and spikelet number, and that having a dysfunctional LUX could have neutral, or even positive, effects in warmer climates. To test the latter hypothesis we ascertained sequence variation of LUX in a range of wheat germplasm. We observed a higher variation in the LUX sequence among accessions coming from the warmer climate and a unique in-frame mutation in early-flowering Chinese T. turgidum cultivar 'Tsing Hua no. 559.' Our results emphasize the importance of the circadian clock in temperate cereals as a promising target for adaptation to new environments.

Original languageEnglish
Pages (from-to)1253-1261
Number of pages9
Issue number4
Publication statusPublished - Apr 2014
Externally publishedYes


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