Abstract
Appropriate timing of flowering is crucial for crop yield and the reproductive success of plants. Flowering can be induced by a number of molecular pathways that respond to internal and external signals such as photoperiod, vernalization or light quality, ambient temperature and biotic as well as abiotic stresses. The key florigenic signal FLOWERING LOCUS T (FT) is regulated by several flowering activators, such as CONSTANS (CO), and repressors, such as FLOWERING LOCUS C (FLC). Chromatin modifications are essential for regulated gene expression, which often involves the well conserved MULTICOPY SUPRESSOR OF IRA 1 (MSI1)-like protein family. MSI1-like proteins are ubiquitous partners of various complexes, such as POLYCOMB REPRESSIVE COMPLEX2 or CHROMATIN ASSEMBLY FACTOR 1. In Arabidopsis, one of the functions of MSI1 is to control the switch to flowering. Arabidopsis MSI1 is needed for the correct expression of the floral integrator gene SUPPRESSOR OF CO 1 (SOC1). Here, we show that the histone-binding protein MSI1 acts in the photoperiod pathway to regulate normal expression of CO in long day (LD) photoperiods. Reduced expression of CO in msi1-mutants leads to failure of FT and SOC1 activation and to delayed flowering. MSI1 is needed for normal sensitivity of Arabidopsis to photoperiod, because msi1-mutants responded less than wild type to an intermittent LD treatment of plants grown in short days. Finally, genetic analysis demonstrated that MSI1 acts upstream of the CO-FT pathway to enable an efficient photoperiodic response and to induce flowering.
Highlights
The reproductive success of plants depends on the appropriate time to flower, which is of great agronomic relevance in crops
MULTICOPY SUPRESSOR OF IRA 1 (MSI1) FUNCTIONS INDEPENDENTLY OF LIGHT QUALITY Previously, we had reported that MSI1 antisense lines and msi1 mutants partially complemented with untagged pMSI1::MSI1 or tagged pMSI1::MSI1:TAP constructs were late flowering (Bouveret et al, 2006)
Msi1-1−/− plants partially complemented with a pMSI1::MSI1:HA construct were late flowering (Supplementary Figure 1)
Summary
The reproductive success of plants depends on the appropriate time to flower, which is of great agronomic relevance in crops. Flowering can be induced by a number of molecular pathways that respond to internal and external signals. Major genetic pathways controlling flowering time have been characterized based on the phenotype of Arabidopsis thaliana flowering time mutants in different growth conditions. These pathways include the photoperiod pathway, which responds to seasonal changes in day length, and the vernalization pathway, which responds to prolonged exposure to cold. The autonomous and gibberellin-pathways mediate the response to endogenous signals. Light quality, ambient temperature, and biotic as well as abiotic stresses can contribute to floral induction in plants (for review see: Jarillo and Piñeiro, 2011; Srikanth and Schmid, 2011)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
