Expression of three galactinol synthase isoforms in Coffea arabica L. and accumulation of raffinose and stachyose in response to abiotic stresses
Expression of three galactinol synthase isoforms in Coffea arabica L. and accumulation of raffinose and stachyose in response to abiotic stresses
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DOI：
10.1016/j.plaphy.2011.01.023
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发表时间：
2011-04-01
影响因子：
6.5
通讯作者：
Vieira, Luiz G. E.
中科院分区：
文献类型：
--
作者：
Bento dos Santos, Tiago;Budzinski, Ilara G. F.;Vieira, Luiz G. E.
半乳糖醇合成酶（EC 2.4.1.123; GolS）催化了棉子糖家族寡糖（RFOs）合成的第一步。它们在非生物胁迫下的积累暗示了rfo在胁迫适应中的作用。本研究对阿拉比卡咖啡中三种半乳糖醇合成酶（CaGolS1-2-3）异构体在水分亏缺、盐胁迫和热胁迫下的表达模式进行了研究。所有的CaGolS异构体在叶片中都有高表达，而在花蕾、花、斜向芽和根中几乎没有表达。成熟果实的胚乳和果皮。转录分析表明，这些基因在水分亏缺、高盐胁迫和热胁迫下存在差异调控。在正常生长条件下，CaGolS1异构体在植物中组成性表达，在所有胁迫处理中反应最强烈。CaGolS2在三种异构体中是独特的，因为它只在严重的水分亏缺和盐胁迫下被检测到。CaGolS3主要在中、重度干旱条件下表达。该异构体仅在高温第3天和高盐胁迫下诱导。GolS转录的增加并没有反映在咖啡叶中半乳糖醇的数量上，因为特定的糖基转移酶很可能利用半乳糖醇将半乳糖单元转移到更高的同源低聚糖上，正如胁迫期间棉子糖和水苏糖的增加所表明的那样。(C) 2011 Elsevier Masson SAS。版权所有。
Galactinol synthase (EC 2.4.1.123; GolS) catalyzes the first step in the synthesis of raffinose family oligosaccharides (RFOs). Their accumulation in response to abiotic stresses implies a role for RFOs in stress adaptation. In this study, the expression patterns of three isoforms of galactinol synthase (CaGolS1-2-3) from Coffea arabica were evaluated in response to water deficit, salinity and heat stress. All CaGolS isoforms were highly expressed in leaves while little to no expression were detected in flower buds, flowers, plagiotropic shoots, roots. endosperm and pericarp of mature fruits. Transcriptional analysis indicated that the genes were differentially regulated under water deficit, high salt and heat stress. CaGolS1 isoform is constitutively expressed in plants under normal growth conditions and was the most responsive during all stress treatments. CaGolS2 is unique among the three isoforms in that it was detected only under severe water deficit and salt stresses. CaGolS3 was primarily expressed under moderate and severe drought. This isoform was induced only at the third day of heat and under high salt stress. The increase in GolS transcription was not reflected into the amount of galactinol in coffee leaves, as specific glycosyltransferases most likely used galactinol to transfer galactose units to higher homologous oligosaccharides, as suggested by the increase of raffinose and stachyose during the stresses. (C) 2011 Elsevier Masson SAS. All rights reserved.