Dormancy Regulator Promotes Ethylene-Mediated Leaf Aging and Shedding

Greg Howard
18th September, 2024

Dormancy Regulator Promotes Ethylene-Mediated Leaf Aging and Shedding

Image Source: Natural Science News, 2024

Key Findings

  • A study from Kyoto University found that the PmDAM6 gene in Japanese apricot leaves is more active in autumn, leading to leaf fall
  • Overexpression of PmDAM6 increases ethylene production, which speeds up leaf aging and detachment
  • The study shows that ethylene plays a crucial role in preparing plants for winter dormancy by promoting leaf senescence and abscission
Leaf senescence and abscission in autumn are vital processes for deciduous woody perennials. These events prepare the plants for winter dormancy, a phase where growth halts until favorable conditions return. A recent study from Kyoto University[1] has unveiled a new function of DORMANCY-ASSOCIATED MADS-box (DAM) transcription factors, specifically PmDAM6, in influencing these autumnal processes in Prunus mume (Japanese apricot). DAM transcription factors are known for their role in controlling bud dormancy in Rosaceae fruit trees. However, their broader biological functions have not been fully explored. This study reveals that PmDAM6, a specific DAM gene, is up-regulated in leaves during autumn, leading up to leaf fall. Through comparative transcriptome analysis of transgenic plants overexpressing PmDAM6 and peach DAM6 (PpeDAM6), the researchers found that Prunus DAM6 up-regulates genes involved in ethylene biosynthesis and signaling, as well as those involved in leaf abscission. Ethylene is a plant hormone known to regulate various aspects of plant growth, including leaf senescence and abscission. The study showed that overexpression of PmDAM6 leads to significant increases in 1-aminocyclopropane-1-carboxylate (ACC) accumulation and ethylene emission in treated leaves. This indicates that PmDAM6 promotes ethylene biosynthesis, accelerating leaf senescence and abscission. Additionally, treatments with ethephon, a compound that releases ethylene, mimicked the effects of PmDAM6 overexpression, further supporting the role of ethylene in these processes. These findings align with previous research indicating the importance of ethylene in plant growth and development. For instance, aquaporins (AQPs), which facilitate water transport across cell membranes, are regulated by ethylene[2]. Specifically, in rose petals, RhPIP1;1, a type of AQP, is down-regulated by ethylene, affecting petal cell expansion through its interaction with RhPIP2;1[2]. This underscores the multifaceted role of ethylene in plant physiology, extending from petal expansion to leaf senescence and abscission. Moreover, the study's results offer insights into how environmental factors influence plant phenology. Previous research has shown that warming temperatures affect the timing of leaf-out in temperate forest trees[3]. Warmer autumns can delay spring phenology by shortening the winter period, which affects dormancy release and subsequent growth cycles[3]. Understanding the role of DAM genes in these processes provides a molecular basis for these phenological changes. In summary, the Kyoto University study elucidates a novel role of PmDAM6 in promoting ethylene biosynthesis, leading to leaf senescence and abscission in autumn. This contributes to the onset of winter dormancy in deciduous woody perennials. The findings highlight the complex interplay between genetic factors and environmental cues in regulating plant growth and dormancy cycles.

GeneticsBiochemPlant Science

References

Main Study

1) Dormancy regulator Prunus mume DAM6 promotes ethylene-mediated leaf senescence and abscission.

Published 16th September, 2024

Journal: Plant molecular biology

Issue: Vol 114, Issue 5, Sep 2024

Related Studies

2) Involvement of rose aquaporin RhPIP1;1 in ethylene-regulated petal expansion through interaction with RhPIP2;1.

https://doi.org/10.1007/s11103-013-0084-6

3) Late to bed, late to rise-Warmer autumn temperatures delay spring phenology by delaying dormancy.

https://doi.org/10.1111/gcb.15858


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