Ethylene antagonizes gibberellin signaling to accelerate petal senescence
Lu, Zhang et al. investigate the mechanisms of phytohormone cross-talk underlying rose petal senescence
By Jingyun Lu, Guifang Zhang, Yunhe Jiang, and Junping Gao
China Agricultural University
https://doi.org/10.1093/plcell/koae035
Background:
Rose (Rosa hybrida) is the queen of flowers, cultivated worldwide for its great economic, symbolic, and cultural importance. Petal senescence is vital for ensuring optimal offspring production, but delaying petal senescence and extending a flower’s longevity have applications in the ornamental flower industry. The timing of petal senescence determines flower longevity and is regulated by phytohormones. Ethylene is the major phytohormone promoting petal senescence, while gibberellic acid (GA) represses this process. The molecular mechanisms underlying the crosstalk between these phytohormones in regulating rose petal senescence remain largely unclear.
Question:
How does ethylene antagonize the effects of GA to accelerate petal senescence?
Findings:
The ethylene-induced F-box protein SENESCENCE-ASSOCIATED F-BOX (RhSAF) accelerates petal senescence by repressing GA signaling in rose. At the early stages of flower opening, the RhGID1 GA receptors are stabilized, as low ethylene levels in petals fail to induce RhSAF expression. During the late stages of flower opening, ethylene levels increase and upregulate RhSAF expression. RhSAF then recognizes RhGID1s and triggers their ubiquitin-mediated degradation through the 26S proteasome, which attenuates GA signaling and accelerates petal senescence.
Next steps:
The present work indicates that additional proteins are RhSAF substrates. It will be interesting to explore their function in phytohormone crosstalk and in regulating petal senescence.
Reference:
Jingyun Lu, Guifang Zhang, Chao Ma, Yao Li, Chuyan Jiang, Yaru Wang, Bingjie Zhang, Rui Wang, Yuexuan Qiu, Yanxing Ma, Yangchao Jia, Cai-Zhong Jiang, Xiaoming Sun, Nan Ma, Yunhe Jiang, Junping Gao. (2024). The F-box protein RhSAF destabilizes the gibberellic acid receptor RhGID1 to mediate ethylene-induced petal senescence in rose. https://doi.org/10.1093/plcell/koae035
