RRC ID 60873
Author Oda A, Higuchi Y, Hisamatsu T.
Title Photoperiod-insensitive floral transition in chrysanthemum induced by constitutive expression of chimeric repressor CsLHY-SRDX.
Journal Plant Sci
Abstract A wide variety of physiological processes including flowering are controlled by the circadian clock in plants. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) constitute the central oscillator, and their gain of function and loss of function disrupt the circadian clock and affect flowering time through FLOWERING LOCUS T (FT), a gene encoding a florigen. Chrysanthemum is a typical short-day (SD) plant and responds to shortening of day length by the transition from the vegetative to reproductive phase. We identified FLOWERING LOCUS T-LIKE 3 (FTL3) and ANTI-FLORIGENIC FT/TFL1 FAMILY PROTEIN (AFT) as a florigen and antiflorigen, respectively, in a wild diploid chrysanthemum (Chrysanthemum seticuspe f. boreale). CsFTL3 and CsAFT are induced under SD or a noninductive photoperiod, respectively, and their balance determines the floral transition and anthesis. Meanwhile, the time-keeping mechanism that regulates the photoperiodic flowering in chrysanthemum is poorly understood. Here, we focused on a LHY/CCA1-like gene called CsLHY in chrysanthemum. We fused CsLHY to a gene encoding short transcriptional repressor domain (SRDX) and constitutively expressed it in chrysanthemum. Although the transcription of clock-related genes was conditionally affected, circadian rhythm was not completely disrupted in CsLHY-SRDX transgenic plants. These plants formed almost the same number of leaves before floral transition under SD and long-day conditions. Thus, CsLHY-SRDX chrysanthemum showed photoperiod-insensitive floral transition, but further development of the capitulum was arrested, and anthesis was not observed. Simultaneously with the flowering phenotype, CsFTL3 and CsAFT were downregulated in CsLHY-SRDX transgenic plants. These results suggest that CsLHY-SRDX affects CsFTL3 and CsAFT expression and causes photoperiod-insensitive floral transition without a severe defect in the circadian clock.
Volume 259
Pages 86-93
Published 2017-6-1
DOI 10.1016/j.plantsci.2017.03.007
PII S0168-9452(16)30774-9
PMID 28483056
MeSH Arabidopsis / genetics Arabidopsis / metabolism Chrysanthemum / genetics Chrysanthemum / metabolism* Chrysanthemum / physiology Circadian Rhythm / genetics Circadian Rhythm / physiology Florigen / metabolism Flowers / genetics Flowers / metabolism* Flowers / physiology Gene Expression Regulation, Plant / genetics Gene Expression Regulation, Plant / physiology Plant Leaves / genetics Plant Leaves / metabolism Plant Proteins / genetics Plant Proteins / metabolism
IF 3.785
Times Cited 3
Chrysanthemum NIFS-3