Early Induction of Apple Fruitlet Abscission Is Characterized by an Increase of Both Isoprene Emission and Abscisic Acid Content
Early Induction of Apple Fruitlet Abscission Is Characterized by an Increase of Both Isoprene Emission and Abscisic Acid Content
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DOI：
10.1104/pp.112.208470
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发表时间：
2013-04-01
期刊：
影响因子：
7.4
通讯作者：
Ramina, Angelo
中科院分区：
文献类型：
--
作者：
Eccher, Giulia;Botton, Alessandro;Ramina, Angelo
苹果（Malus acutitica）幼果脱落是研究脱落过程早期阶段的一个有趣的模型系统，在此期间果实内发生主要的转录组变化和代谢重排。在苹果中，通过化学稀释剂，如苄基腺嘌呤和苯并咪唑，可以选择性地放大簇内不同位置的果实的脱落，作为脱落增强剂。在本研究中，通过上述稀释剂，在苹果幼果群体中获得了不同的剥离潜力。代谢组学的研究进行了挥发性有机化合物释放的小果实，允许识别异戊二烯作为一个早期标志物的诱导。异戊二烯的产生和脱落酸（阿坝）的水平在水果皮层，这被证明是增加与nondischargising的在dischargising的小果实之间也观察到了很强的相关性。转录组学证据表明，脱落相关的阿坝具有生物活性，其生物合成增加与特定ABA响应9-顺式-环氧类胡萝卜素双加氧酶基因的诱导有关。根据一个假设的模型，阿坝可能会短暂地与其他激素和第二信使在产生一个果内信号，导致下游激活的释放区。因此，脱落过程似乎是由多个相互依赖的途径，其精细的调节，施加在一个非常短的时间窗口内的内源性和外源性因素，决定了最终的命运的小果实。
Apple (Malus domestica) fruitlet abscission represents an interesting model system to study the early phases of the shedding process, during which major transcriptomic changes and metabolic rearrangements occur within the fruit. In apple, the drop of fruits at different positions within the cluster can be selectively magnified through chemical thinners, such as benzyladenine and metamitron, acting as abscission enhancers. In this study, different abscission potentials were obtained within the apple fruitlet population by means of the above-cited thinners. A metabolomic study was conducted on the volatile organic compounds emitted by abscising fruitlets, allowing for identification of isoprene as an early marker of abscission induction. A strong correlation was also observed between isoprene production and abscisic acid (ABA) levels in the fruit cortex, which were shown to increase in abscising fruitlets with respect to nonabscising ones. Transcriptomic evidence indicated that abscission-related ABA is biologically active, and its increased biosynthesis is associated with the induction of a specific ABA-responsive 9-cis-epoxycarotenoid dioxygenase gene. According to a hypothetical model, ABA may transiently cooperate with other hormones and secondary messengers in the generation of an intrafruit signal leading to the downstream activation of the abscission zone. The shedding process therefore appears to be triggered by multiple interdependent pathways, whose fine regulation, exerted within a very short temporal window by both endogenous and exogenous factors, determines the final destiny of the fruitlets.