Aug 2026· Communications Biology· Vol 9· 0 citations· 47 references
Medicine
TL;DR
A two-nucleotide deletion shortens a key floral protein, weakening its ability to activate flowering and explaining why Maryland Mammoth tobacco, central to the discovery of photoperiodism over 100 years ago, only flowers under short days.
Abstract
Flowering in day-neutral tobacco (Nicotiana tabacum) cultivars requires the photoperiod-dependent expression of FLOWERING LOCUS T (FT)-like floral activators, which compete with FT-like inhibitors to interact with FD proteins and induce the switch from vegetative to reproductive growth. In the short-day (SD) cultivar Maryland Mammoth (MM), vegetative growth persists under long-day (LD) conditions, generating unusually tall plants. We found that overexpression of the major LD floral inducer (NtFT5) from the day-neutral cultivar Hicks induces flowering in MM plants under LD conditions. However, a 2-bp deletion near the end of the endogenous NtFT5MM gene generates a truncated NtFT5MM protein that still interacts with FD proteins but acts as a weaker floral inducer than NtFT5. The truncation does not impair NtFT5MM protein stability but may affect its binding to NtFD1, weakening the expression of target genes. Our results provide a potential explanation for the MM gigantism phenotype first observed more than 100 years ago. A two-nucleotide deletion shortens a key floral protein, weakening its ability to activate flowering and explaining why Maryland Mammoth tobacco, central to the discovery of photoperiodism over 100 years ago, only flowers under short days.
Evidence is provided suggesting that StFKF1 influences the timing of flowering and tuber initiation, as well as the expression patterns of key regulatory genes, under long-day conditions, thereby contributing to a theoretical foundation for understanding developmental transitions in this specific environmental context.
Zefeng Zhai, Yongguang Liu, Haicai Li et al.· Molecular breeding· 0 citations
It is shown that the loss of BnFLC genes significantly accelerates flowering, demonstrating that BnFLC genes regulate flowering in spring types independently of vernalization, and that these genes regulate flowering time developmentally in spring oilseed rape.
Sarah Duveneck, Kea Ille, S. Melzer· Plant Molecular Biology· 0 citations
Soybean (Glycine max) is a photoperiod-sensitive legume whose latitudinal adaptation depends on the precise control of flowering time and plant height. Histone demethylases of the JmjC domain-containing (JMJ) protein family have been implicated in these processes across plant species, but their specific roles in soybean remain largely unexplored. Here, we identify soybean GmJMJ19 and GmJMJ20, two closely related JMJD5/KDM8 orthologs, as master epigenetic regulators that coordinately control both photoperiodic flowering and post-flowering plant height. Both genes exhibit intrinsic, rhythmic expression peaking at ZT12, and their encoded proteins physically interact with the florigen proteins FT2a and FT5a. Loss-of-function mutants display delayed flowering under long days (LDs) and increased plant height under both LDs and short days (SDs), whereas overexpression phenocopies the mutant flowering phenotype, indicating revealing a critical dosage requirement for proper function. Mechanistically, GmJMJ19 and GmJMJ20 are recruited by the FT/FD transcriptional complex to directly activate AP1a and AP1c expression through chromatin modulation. Population genomic analyses reveal distinct selection signatures: GmJMJ19 underwent sustained directional selection during cultivation, whereas GmJMJ20 experienced an early domestication sweep with limited subsequent change. Haplotype analysis identifies coordinated latitudinal clines, with the JMJ19H1/JMJ20H1 combination predominating at high latitudes to promote early flowering and limit height, while JMJ19H2/JMJ20H2 and wild JMJ19H3/JMJ20H3 alleles prevail at low latitudes, conferring later flowering and increased height. Collectively, our findings establish GmJMJ19 and GmJMJ20 as central chromatin regulators linking florigen signaling to downstream target expression and provide valuable allelic resources for breeding regionally adapted soybean varieties across a wide range of latitudinal environments.
Xiu-Lin Liu, Cheng-Yang Song, Yuan-Yuan Cui et al.· Plant Communications· 0 citations
Findings implicate GRF21 as a negative regulator of flowering time in maize, as evidenced by the delayed flowering phenotype associated with its overexpression, and highlights GRF21 as a promising target for maize breeding.
Z. Deng, Nipapan Kanjana, Jinghui Dong et al.· BMC Plant Biology· 0 citations
These findings establish OsDPMS1 as a critical regulator of pistil development and female fertility in rice and highlight its potential application in hybrid rice breeding programs.
It is established that CmELF4-LIKE 3 interacts with CmPIF7 to cooperatively regulate short-day-induced flowering in chrysanthemum, and offers new insights into the crosstalk between the circadian clock and light signaling pathways in plants.
Wan-Wan Zhang, Binyao Yin, Yvhan Ye et al.· Physiologia Plantarum : An I...· 0 citations
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