Kevany Brian M, Tieman Denise M, Taylor Mark G, Cin Valeriano Dal, Klee Harry J
Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611-0690, USA.
Plant J. 2007 Aug;51(3):458-67. doi: 10.1111/j.1365-313X.2007.03170.x.
Fruit ripening in tomato requires the coordination of both developmental cues and the phytohormone ethylene. The multigene ethylene receptor family has been shown to negatively regulate ethylene signal transduction and suppress ethylene responses. Here we demonstrate that reduction in the levels of either of two family members, LeETR4 or LeETR6, causes an early-ripening phenotype. We provide evidence that the receptors are rapidly degraded in the presence of ethylene, and that degradation probably occurs through the 26S proteasome-dependent pathway. Ethylene exposure of immature fruits causes a reduction in the amount of receptor protein and earlier ripening. The results are consistent with a model in which receptor levels modulate timing of the onset of fruit ripening by measuring cumulative ethylene exposure.
番茄果实成熟需要发育信号和植物激素乙烯的协同作用。多基因乙烯受体家族已被证明对乙烯信号转导起负调控作用,并抑制乙烯反应。在此,我们证明两个家族成员LeETR4或LeETR6中任何一个水平的降低都会导致早熟表型。我们提供的证据表明,在乙烯存在的情况下,受体迅速降解,且这种降解可能通过26S蛋白酶体依赖性途径发生。未成熟果实暴露于乙烯中会导致受体蛋白数量减少并提前成熟。这些结果与一个模型一致,即受体水平通过测量累积的乙烯暴露量来调节果实成熟开始的时间。