Epistatic interactions between PHOTOPERIOD1, CONSTANS1 and CONSTANS2 modulate the photoperiodic response in wheat

Autoři: Lindsay M. Shaw aff001;  Chengxia Li aff001;  Daniel P. Woods aff001;  Maria A. Alvarez aff001;  Huiqiong Lin aff001;  Mei Y. Lau aff001;  Andrew Chen aff001;  Jorge Dubcovsky aff001
Působiště autorů: Department of Plant Sciences, University of California, Davis, California, United States of America aff001;  Currently at Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD, Australia aff002;  Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America aff003
Vyšlo v časopise: Epistatic interactions between PHOTOPERIOD1, CONSTANS1 and CONSTANS2 modulate the photoperiodic response in wheat. PLoS Genet 16(7): e32767. doi:10.1371/journal.pgen.1008812
Kategorie: Research Article
doi: 10.1371/journal.pgen.1008812


In Arabidopsis, CONSTANS (CO) integrates light and circadian clock signals to promote flowering under long days (LD). In the grasses, a duplication generated two paralogs designated as CONSTANS1 (CO1) and CONSTANS2 (CO2). Here we show that in tetraploid wheat plants grown under LD, combined loss-of-function mutations in the A and B-genome homeologs of CO1 and CO2 (co1 co2) result in a small (3 d) but significant (P<0.0001) acceleration of heading time both in PHOTOPERIOD1 (PPD1) sensitive (Ppd-A1b, functional ancestral allele) and insensitive (Ppd-A1a, functional dominant allele) backgrounds. Under short days (SD), co1 co2 mutants headed 13 d earlier than the wild type (P<0.0001) in the presence of Ppd-A1a. However, in the presence of Ppd-A1b, spikes from both genotypes failed to emerge by 180 d. These results indicate that CO1 and CO2 operate mainly as weak heading time repressors in both LD and SD. By contrast, in ppd1 mutants with loss-of-function mutations in both PPD1 homeologs, the wild type Co1 allele accelerated heading time >60 d relative to the co1 mutant allele under LD. We detected significant genetic interactions among CO1, CO2 and PPD1 genes on heading time, which were reflected in complex interactions at the transcriptional and protein levels. Loss-of-function mutations in PPD1 delayed heading more than combined co1 co2 mutations and, more importantly, PPD1 was able to perceive and respond to differences in photoperiod in the absence of functional CO1 and CO2 genes. Similarly, CO1 was able to accelerate heading time in response to LD in the absence of a functional PPD1. Taken together, these results indicate that PPD1 and CO1 are able to respond to photoperiod in the absence of each other, and that interactions between these two photoperiod pathways at the transcriptional and protein levels are important to fine-tune the flowering response in wheat.

Klíčová slova:

Arabidopsis thaliana – Flowering plants – Leaves – Mutation – Protein interactions – Rice – Transcriptional control – Wheat


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