The Manipulation of Auxin in the Abscission Zone Cells of Arabidopsis Flowers Reveals That Indoleacetic Acid Signaling Is a Prerequisite for Organ Shedding
The Manipulation of Auxin in the Abscission Zone Cells of Arabidopsis Flowers Reveals That Indoleacetic Acid Signaling Is a Prerequisite for Organ Shedding
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DOI：
10.1104/pp.113.216234
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发表时间：
2013-05-01
期刊：
影响因子：
7.4
通讯作者：
Roberts, Jeremy A.
中科院分区：
文献类型：
--
作者：
Basu, Manojit M.;Gonzalez-Carranza, Zinnia H.;Roberts, Jeremy A.
本研究采用了多种新的策略来研究吲哚乙酸（IAA）在拟南芥（Arabidopsis thaliana）花器官发育中的调控作用。在β-葡萄糖醛酸酶报告植物中生长素流入促进剂表达的分析显示，生长素抗性1，如AUX 1和LAX 3在花器官脱落的位点特异性上调。花的突变体，其中个别家庭成员被下调表现出减少所需的力量，使花瓣分离，然而，效果是不加性的双重或四重突变体。使用启动子的多聚半乳糖醛酸酶（At 2g 41850），活性主要在细胞进行分离，驱动细菌基因iaaL和iaaM的表达，我们已经表明，它是可能的操纵生长素活性，特别是在花器官的增殖区（AZ）。花瓣断裂强度的分析表明，如果IAA AZ水平降低，脱落过早发生，而如果它们增强，器官损失延迟。At 2g 41850启动子也用于反式激活功能获得性AXR 3 -1基因，以特异性地破坏花器官AZ细胞内的生长素信号传导。反式激活线的花未能脱落他们的萼片，花瓣和花药在荚果扩张和成熟，这些器官经常保持附着在植物，即使在角果干燥和开裂已经发生。这些观察结果支持IAA在调节植物脱落中的关键作用，并首次揭示了AZ细胞中发生器官脱落的功能性IAA信号通路的要求。
A number of novel strategies were employed to examine the role of indoleacetic acid (IAA) in regulating floral organ abscission in Arabidopsis (Arabidopsis thaliana). Analysis of auxin influx facilitator expression in beta-glucuronidase reporter plants revealed that AUXIN RESISTANT1, LIKE AUX1, and LAX3 were specifically up-regulated at the site of floral organ shedding. Flowers from mutants where individual family members were down-regulated exhibited a reduction in the force necessary to bring about petal separation; however, the effect was not additive in double or quadruple mutants. Using the promoter of a polygalacturonase (At2g41850), active primarily in cells undergoing separation, to drive expression of the bacterial genes iaaL and iaaM, we have shown that it is possible to manipulate auxin activity specifically within the floral organ abscission zone (AZ). Analysis of petal breakstrength reveals that if IAA AZ levels are reduced, shedding takes place prematurely, while if they are enhanced, organ loss is delayed. The At2g41850 promoter was also used to transactivate the gain-of-function AXR3-1 gene in order to disrupt auxin signaling specifically within the floral organ AZ cells. Flowers from transactivated lines failed to shed their sepals, petals, and anthers during pod expansion and maturity, and these organs frequently remained attached to the plant even after silique desiccation and dehiscence had taken place. These observations support a key role for IAA in the regulation of abscission in planta and reveal, to our knowledge for the first time, a requirement for a functional IAA signaling pathway in AZ cells for organ shedding to take place.