Genes involved in ethylene and gibberellins metabolism are required for endosperm-limited germination of Sisymbrium officinale L. seeds
Genes involved in ethylene and gibberellins metabolism are required for endosperm-limited germination of Sisymbrium officinale L. seeds
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DOI：
10.1007/s00425-009-1073-5
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发表时间：
2010-02-01
期刊：
影响因子：
4.3
通讯作者：
Matilla, Angel J.
中科院分区：
文献类型：
--
作者：
Iglesias-Fernandez, Raquel;Matilla, Angel J.
种皮的破裂和胚乳的破裂是西茜草种子萌发过程中连续发生的两个事件，胚根的突出并不完全发生在微孔区，而是发生在邻近区域。赤霉素（GA(4+7)）和乙烯利存在时，萌发模式相似。对GAs合成和分解相关基因的分析表明：(1)SoGA2ox6的表达在胚根突出前达到峰值（20 ~ 22 h），而SoGA3ox2和SoGA20ox2的表达在吸胀早期（6 h）达到峰值，此后急剧下降；(2) SoGA20ox2转录物的积累在抑制后早期（6 h）受到多效唑（PB）和ET合成和信号传导抑制剂（IESS）的强烈抑制，而SoGA3ox2和SoGA2ox6的表达随着萌发的进行而缓慢下降；(3)乙烯利和GA（4+7）对SoGA3ox2、SoGA20ox2和SoGA2ox6的表达有正向或负向影响，影响程度取决于所研究的萌发期。对于参与ET合成的基因，我们的研究结果表明，SoACS7在胚根出现之前表达，而SoACO2的表达随着发芽的进行而缓慢增加。PB对这两个基因均有较强的抑制作用，但外源添加乙烯利或GA对其影响不大（4+7）。这些结果表明，气体在吸胀早期比ET更重要，而ET在萌发后期更重要。
The rupture of the seed coat and that of the endosperm were found to be two sequential events in the germination of Sisymbrium officinale L. seeds, and radicle protrusion did not occur exactly in the micropylar area but in the neighboring zone. The germination patterns were similar both in the presence of gibberellins (GA(4+7)) and in presence of ethrel. The analysis of genes involved in GAs synthesis and breakdown demonstrated that (1) SoGA2ox6 expression peaked just prior to radicle protrusion (20-22 h), while SoGA3ox2 and SoGA20ox2 expression was high at early imbibition (6 h) diminishing sharply thereafter; (2) the accumulation of SoGA20ox2 transcript was strongly inhibited by paclobutrazol (PB) as well as by inhibitors of ET synthesis and signaling (IESS) early after imbibition (6 h), while SoGA3ox2 and SoGA2ox6 expression was slowly depressed as germination progressed; (3) ethrel and GA(4+7) positively or negatively affected expression of SoGA3ox2, SoGA20ox2, and SoGA2ox6, depending on the germination period studied. Regarding genes involved in ET synthesis, our results showed that SoACS7 was expressed, just prior to radicle emergence while SoACO2 expression slowly increased as germination progressed. Both genes were strongly inhibited by PB but were almost unaffected by externally added ethrel or GA(4+7). These results suggest that GAs are more important than ET during the early stages of imbibition, while ET is more important at the late phases of germination of S. officinale L. seeds.