Ethylene-regulated floral volatile synthesis in petunia corollas
Ethylene-regulated floral volatile synthesis in petunia corollas
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DOI：
10.1104/pp.104.051144
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发表时间：
2005-05-01
期刊：
影响因子：
7.4
通讯作者：
Clark, DG
中科院分区：
文献类型：
--
作者：
Underwood, BA;Tieman, DM;Clark, DG
在许多开花植物中，如矮牵牛（Petunia 3 hybrida），授粉后花器官中产生的乙烯引发一系列生理生化事件，最终导致花瓣衰老和受精成功。在这里，我们证明，使用转基因乙烯不敏感（44568）和米切尔二倍体矮牵牛，挥发性有机化合物（VOCs）的排放的多个组件是由乙烯调节。苯甲酸/水杨酸羧甲基转移酶（PhBSMT 1和2）mRNA的表达在花器官中的时间和空间下调的方式与目前的模型授粉后乙烯合成矮牵牛花冠。授粉和外源乙烯处理后苯甲酸甲酯和其他挥发性有机物的排放与PhBSMT 1和2 mRNA水平的降低平行。在周期性光照条件下（白天/夜晚），PhBSMT mRNA水平是有节奏的，并在苯甲酸甲酯释放前约6小时。当转移到恒定的黑暗或光照条件下，PhBSMT mRNA水平和随后的苯甲酸甲酯发射相应地减少或增加到正常条件下观察到的最小或最大水平，从而表明光可能是一个更关键的影响比昼夜节律钟的苯甲酸甲酯的循环发射。具有降低的PhBSMT mRNA水平的转基因PhBSMT RNAi花显示苯甲酸甲酯排放减少75%至99%，而其他矮牵牛VOC的变化最小。这些结果暗示PhBSMT 1和2作为负责合成苯甲酸甲酯的基因在矮牵牛。
In many flowering plants, such as petunia ( Petunia 3 hybrida), ethylene produced in floral organs after pollination elicits a series of physiological and biochemical events, ultimately leading to senescence of petals and successful fertilization. Here, we demonstrate, using transgenic ethylene insensitive ( 44568) and Mitchell Diploid petunias, that multiple components of emission of volatile organic compounds ( VOCs) are regulated by ethylene. Expression of benzoic acid/ salicylic acid carboxyl methyltransferase ( PhBSMT1 and 2) mRNA is temporally and spatially down- regulated in floral organs in a manner consistent with current models for postpollination ethylene synthesis in petunia corollas. Emission of methylbenzoate and other VOCs after pollination and exogenous ethylene treatment parallels a reduction in PhBSMT1 and 2mRNAlevels. Under cyclic light conditions ( day/ night), PhBSMT mRNA levels are rhythmic and precede emission of methylbenzoate by approximately 6 h. When shifted into constant dark or light conditions, PhBSMT mRNA levels and subsequent methylbenzoate emission correspondingly decrease or increase to minimum or maximum levels observed during normal conditions, thus suggesting that light may be a more critical influence on cyclic emission of methylbenzoate than a circadian clock. Transgenic PhBSMT RNAi flowers with reduced PhBSMT mRNA levels show a 75% to 99% decrease in methylbenzoate emission, with minimal changes in other petunia VOCs. These results implicate PhBSMT1 and 2 as genes responsible for synthesis of methylbenzoate in petunia.