Cold Exposure Helps Sugar Beet Grow Faster by Stopping Growth-Inhibiting Genes

Greg Howard
5th June, 2024

Cold Exposure Helps Sugar Beet Grow Faster by Stopping Growth-Inhibiting Genes

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Heilongjiang University studied the regulatory factors of the GIGANTEA (GI) gene in sugar beet, which is crucial for flowering
  • They identified three transcription factors (BvLHY, BvTCP4, and BvCRF4) that negatively regulate the GI gene by inhibiting its promoter
  • The study reveals that vernalization and photoperiod interact to initiate flowering in sugar beet by inhibiting these transcriptional repressors, aiding in crop yield optimization
Understanding the mechanisms behind the transition from vegetative to reproductive growth in plants is crucial for optimizing crop yields. This is particularly significant for sugar beet (Beta vulgaris L.), a biennial crop that contributes about 16% of the world's sugar production. The transition phase, which affects sugar accumulation, is influenced by vernalization (prolonged exposure to cold) and photoperiod (day length). Researchers at Heilongjiang University have conducted a study to identify the upstream regulatory factors of the GIGANTEA (GI) gene in sugar beet, a key photoperiodic flowering gene induced by vernalization[1]. The study aimed to uncover the transcription factors (TFs) that regulate BvGI, the GI gene in sugar beet. Using weighted gene co-expression network analysis (WGCNA) and TF binding site prediction, the researchers screened candidate TFs that were co-expressed with BvGI and could bind to its promoter. They identified 7,586 differentially expressed genes after vernalization and divided them into 18 co-expression modules. Among these, one module (MEcyan) was positively correlated with BvGI expression, while two modules (MEdarkorange2 and MEmidnightblue) were negatively correlated. To validate the transcriptional regulatory roles of the identified TFs on BvGI, the researchers used subcellular localization, dual-luciferase assays, and yeast transformation tests. They discovered that BvLHY, BvTCP4, and BvCRF4 were candidate TFs that negatively regulated BvGI expression by affecting its transcription. Subcellular localization confirmed that these TFs were localized in the nucleus, indicating their potential role in gene regulation within the cell's control center. Dual-luciferase assays and yeast transformation tests further demonstrated that the relative luciferase activity and expression of HIS3 were reduced in the BvLHY, BvTCP4, and BvCRF4 transformants. This suggested that these TFs inhibited the BvGI promoter. Additionally, real-time quantitative reverse transcription PCR showed that BvLHY and BvTCP4 exhibited rhythmic expression patterns similar to BvGI, while BvCRF4 did not. The findings of this study are significant as they reveal that vernalization interacts with the photoperiod pathway to initiate bolting (the transition to reproductive growth) in sugar beet by inhibiting the transcriptional repressors of BvGI. This insight helps in understanding the complex regulatory network governing floral transition, which is crucial for maximizing reproductive success in plants. Previous studies have highlighted the role of GI in various biological functions, including light signaling, cold tolerance, and photoperiodic flowering. GI's central role in flowering involves multiple pathways, both dependent and independent of the CONSTANS (CO) gene, and interactions with microRNAs[2]. This new study builds on these findings by identifying specific TFs that regulate BvGI in sugar beet, thereby advancing our understanding of the molecular mechanisms underlying vernalization and photoperiodic flowering. Moreover, the study's findings align with earlier research on the role of GI in temperature-regulated flowering. For instance, HOS15, a GI transcriptional repressor, controls flowering time in response to low ambient temperatures by regulating GI protein abundance[3]. This new study extends the understanding of GI regulation by identifying additional TFs that modulate its expression in response to environmental cues. Additionally, the study's focus on transcriptional regulation adds to the existing knowledge of how phytohormones and genetic pathways interact to control flowering time. Previous research has shown that gibberellin (GA) plays a major role in affecting flowering in Arabidopsis thaliana through DELLA proteins and GA homeostasis[4]. The identification of BvLHY, BvTCP4, and BvCRF4 as regulators of BvGI provides further insight into the complex interplay between genetic and environmental factors in flowering regulation. In summary, the study conducted by Heilongjiang University provides valuable insights into the regulatory mechanisms of the GI gene in sugar beet, highlighting the role of vernalization and photoperiod in floral transition. By identifying and validating the transcription factors that regulate BvGI, this research advances our understanding of the molecular basis of flowering time control, which is crucial for optimizing crop yields and ensuring food security.

GeneticsBiochemPlant Science

References

Main Study

1) Vernalization promotes bolting in sugar beet by inhibiting the transcriptional repressors of BvGI.

Published 5th June, 2024

Journal: Plant molecular biology

Issue: Vol 114, Issue 3, Jun 2024

Related Studies

2) Gigantea: Uncovering New Functions in Flower Development.

https://doi.org/10.3390/genes11101142

3) HOS15 represses flowering by promoting GIGANTEA degradation in response to low temperature in Arabidopsis.

https://doi.org/10.1016/j.xplc.2023.100570

4) New insights into gibberellin signaling in regulating flowering in Arabidopsis.

https://doi.org/10.1111/jipb.12892


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