Sequestration of auxin by the indole-3-acetic acid-amido synthetase GH3-1 in grape berry (Vitis vinifera L.) and the proposed role of auxin conjugation during ripening
Sequestration of auxin by the indole-3-acetic acid-amido synthetase GH3-1 in grape berry (Vitis vinifera L.) and the proposed role of auxin conjugation during ripening
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DOI：
10.1093/jxb/erq174
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发表时间：
2010-08-01
影响因子：
6.9
通讯作者：
Davies, Christopher
中科院分区：
文献类型：
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作者：
Boettcher, Christine;Keyzers, Robert A.;Davies, Christopher
在肉质果实中，吲哚-3-乙酸（IAA）的水平，最丰富的生长素，下降对成熟的开始。在未成熟果实上施用生长素可以延缓果实的成熟过程。然而，成熟果实内源IAA浓度降低和生长素低水平维持的机制仍然是难以捉摸的。在葡萄浆果（葡萄属vinifera L.）中检测到编码IAA-酰胺合成酶的基因GH 3 -1的转录本。GH 3 -1的表达增加，在成熟（veraison）的发病，这表明它可能参与建立和维持低IAA浓度的成熟浆果。此外，该葡萄藤GH 3基因对脱落酸和蔗糖以及乙烯的联合应用做出积极反应，将其与成熟过程的控制联系起来。IAA-天冬氨酸（IAA-Asp），重组GH 3 -1的体外产物的水平，上升veraison后，并保持高水平，在以下几周的成熟阶段时，游离IAA水平低。在发育中的番茄（Solanum lycopersicum Mill.）中检测到游离IAA和IAA-Asp水平的类似变化模式，其中低浓度的IAA和IAA-Asp浓度的增加与此跃变型果实成熟的开始相一致。由于IAA-Asp可能参与IAA降解，GH 3在成熟开始时和成熟开始后催化形成这种缀合物可能代表了跃变型和非跃变型果实中使成熟成为可能的常见IAA失活机制。
In fleshy fruit, levels of indole-3-acetic acid (IAA), the most abundant auxin, decline towards the onset of ripening. The application of auxins to immature fruit can delay the ripening processes. However, the mechanisms by which the decrease in endogenous IAA concentrations and the maintenance of low auxin levels in maturing fruit are achieved remain elusive. The transcript of a GH3 gene (GH3-1), encoding for an IAA-amido synthetase which conjugates IAA to amino acids, was detected in grape berries (Vitis vinifera L.). GH3-1 expression increased at the onset of ripening (veraison), suggesting that it might be involved in the establishment and maintenance of low IAA concentrations in ripening berries. Furthermore, this grapevine GH3 gene, responded positively to the combined application of abscisic acid and sucrose and to ethylene, linking it to the control of ripening processes. Levels of IAA-aspartic acid (IAA-Asp), an in vitro product of recombinant GH3-1, rose after veraison and remained high during the following weeks of the ripening phase when levels of free IAA were low. A similar pattern of changes in free IAA and IAA-Asp levels was detected in developing tomatoes (Solanum lycopersicum Mill.), where low concentrations of IAA and an increase in IAA-Asp concentrations coincided with the onset of ripening in this climacteric fruit. Since IAA-Asp might be involved in IAA degradation, the GH3 catalysed formation of this conjugate at, and after, the onset of ripening could represent a common IAA inactivation mechanism in climacteric and non-climacteric fruit which enables ripening.