Reduced embryo sensitivity to abscisic acid in a sprouting-susceptible sorghum (Sorghum bicolor) variety is associated with altered ABA signalling
Reduced embryo sensitivity to abscisic acid in a sprouting-susceptible sorghum (Sorghum bicolor) variety is associated with altered ABA signalling
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DOI：
10.1017/s0960258507708115
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发表时间：
2007-06-01
影响因子：
2.1
通讯作者：
Benech-Arnold, Roberto
中科院分区：
文献类型：
--
作者：
Gualano, Nicolas;Carrari, Fernando;Benech-Arnold, Roberto
在本文报道的工作中，我们试图阐明不同的脱落酸（阿坝）敏感性的本质所提出的发育胚胎高粱[Sorcumbicolor（L.）Moench]品系具有对比的收获前发芽（PHS）行为（Redand B2，敏感，IS 9530，抗性）。我们探讨了两种不同的假说的一种可能的机制：（1）阿坝信号通路的不同功能，和（2）不同的阿坝降解率/接合在质外体的胚胎从这些基因型。为了评估第一种可能性，我们使用了ABA响应基因（Rab 17）作为内源阿坝含量变化的报告者，这是人工诱导的胚胎从两种基因型通过氟虫腈应用开花后立即，以减少阿坝含量，和胚胎孵化在阿坝的存在下。阿坝信号传导的缺陷应被视为Rab 17表达水平独立于内源阿坝含量。为了在两个发育阶段测试第二种可能性，将来自两个品系的胚胎分离并在水中孵育不同的时期。通过放射免疫测定法对胚胎和培养液中的阿坝浓度进行定量。相反，我们的研究结果的抗性IS 9530线，Rab 17的表达没有响应阿坝水平的变化，敏感的Redland B2胚胎。阿坝degraclation/共轭率在胚胎和孵育介质中没有表现出明显的差异高粱线的任何分析的发展阶段。这些结果表明，红地B2中阿坝信号转导途径的中断是该系胚表现出的低阿坝敏感性的基础。
In the work reported in this paper, we attempted to elucidate the nature of the different abscisic acid (ABA) sensitivities presented by developing embryos from sorghum [Sorghum bicolor (L.) Moench] lines with contrasting pre-harvest sprouting (PHS) behaviour (Redand B2, susceptible, IS 9530, resistant). We explored two different hypotheses for a possible mechanism: (1) a different functionality of the ABA signalling pathway, and (2) a different rate of ABA degradation/conjugation in the apoplast of embryos from these genotypes. To assess the first possibility, we used an ABA-responsive gene (Rab17) as a reporter of changes in endogenous ABA content, which were artificially induced in embryos from both genotypes by means of fluriclone application immediately after anthesis, to reduce ABA content, and embryo incubation in the presence of ABA. A defect in ABA signalling should be seen as a level of Rab17 expression that is independent of endogenous ABA content. For testing the second possibility at two stages of development, embryos from both lines were isolated and incubated in water for different periods. ABA concentrations in embryos and the incubation media were quantified through radioimmunoassay. In contrast to our findings for the resistant IS 9530 line, Rab 17 expression did not respond to changes in ABA levels in sensitive Redland B2 embryos. The ABA degraclation/conjugation rates in embryos and incubation media did not show clear differences between sorghum lines for any of the developmental stages analysed. These results suggest that a disruption in the ABA signal transduction pathway in Redland B2 underlies the low ABA sensitivity shown by embryos from this line.